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Publication numberUS3683303 A
Publication typeGrant
Publication dateAug 8, 1972
Filing dateAug 6, 1970
Priority dateApr 4, 1966
Also published asDE1665121B1
Publication numberUS 3683303 A, US 3683303A, US-A-3683303, US3683303 A, US3683303A
InventorsHiroyoshi Ayano, Minoru Fukuhara, Yasuaki Kibino, Yukihiko Ohta, Hiroyoshi Sato
Original AssigneeHiroyoshi Ayano, Hiroyoshi Sato, Minoru Fukuhara, Yasuaki Kibino, Yukihiko Ohta
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Compound for electric devices
US 3683303 A
Abstract
A method providing for the reduction of noise originating from core-and-coil elements of electrical devices by encasing the core-and-coil elements within a chemical compound combination comprising at least two organic compounds, the combination having large d -loss factor values at starting and stabilization temperatures, respectively, of the core-and-coil elements. A typical mixture comprises an unsaturated polyester and a polyurethane.
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United States Patent Ayano et al.

COMPOUND FOR ELECTRIC DEVICES Inventors: Hiroyoshi Ayano; Yasuaki Kibino; Hiroyoshi Sato; Yukihiko Ohta; Minoru Fukuhara, all of 1048 Oaza Kakoma, Kadoma-shi, Osaka, Japan Filed: Aug. 6, 1970 Appl. No.: 61,776

Related US. Application Data Continuation-in-part of Ser. No. March 29, 1967, abandoned.

Foreign Application Priority Data April 4, 1966 Japan ..41/21071 Oct. 7, 1966 Japan ...41/65655 Oct. 11, 1966 Japan ...41/67353 Oct. 17, 1966 Japan ...41/67821 Oct. 17, 1966 Japan ...41/67822 Nov. 9, 1966 Japan ..41/73729 US. Cl. ..336/96, 260/28, 260/37,

Int. Cl ..HOlf 15/02 Field of Search ..336/96, 100, 205; 264/272; 174/52 PE, DIG. 2; 26 0/28, 37 N, 858

References Cited UNITED STATES PATENTS 9/1968 Holzinger ..336/96 Aug. 8, 1972 2,464,568 3/1949 Flynn et al ..336/96 3,235,825 2/1966 Davis, Jr ..336/96 x 2,414,525 1/1947 Hiyl et al. ..336/96 3,488,616 1/1970 Duncan et a1. ..336/96 3,319,203 5/1967 Haughney ..336/96 2,788,499 4/1957 Pappas ....336/96 x 3,102,246 8/1963 Honey et al. ..336/100 1,769,906 7/1930 Cameron ..336/96 2,484,215 10/1949 FQStCl' ..336/96 3,163,838 12/1964 Antalis e! 111.... ....336/96 x 3,211,695 10/1965 Peterson ..336/96 x Primary Examiner-Thomas J. Kozma Att0rneyWolfe, Hubbard, Leydig, Voit & Osann, Ltd.

[57] ABSTRACT A method providing for the reduction of noise originating from core-and-coil elements of electrical devices by encasing the core-and-coil elements within a chemical compound combination comprising at least two organic compounds, the combination having large d-loss factor values at starting and stabilization temperatures, respectively, of the core-and-coil elements. A typical mixture comprises an unsaturated polyester and a polyurethane.

5 Claims, 22 Drawing Figures H Hg 2 Loss Factor Loss Factor 0 50 I00 o 0 5o |oo c Temperature Temperature F/g. 3 AQ 4 Z 5 LI E 0 50 I00 C 0 50 [00 C Temperature Temperature Phone 5 Phone 6 20 2o L/ TO I Noise Name 0 50 I00 c 0 50 too Compound Temperature Compound Temperature [NVENTORS Huzovosm AYANO YASUAKI K/B/NO Hnzovosm SATO YUklHIKO OHTA MINORU FUKUHAQA a n/31, MM, 'I/aTd-GM ATTYS PATENTED M19 81972 SHEET 2 BF 5 Phone 8 I6 |5- I I z I [0. g I 1 0'03 o'oe ooe Loss Factor Phone Hg. 7 F/g. 9

20 Phone 10 I0 g i O 50 I00 C 0 50 I00 "C Compound Temperorure Compound Temperature F/ /0 Phone 9 Phone 0) g IO 2 2 O 50 IOO C 0 50 I00 C Compound Temperofure Compound TemperoTure [.N'VENTORS HIROYOSHI Awwo YASUAKI memo Hmovosm SATo YUKIHIKO OHTA MINORU FUKUHARA 1: 1 /0470, MM, VJq-QMZMATTYS.

P'ATENTEDAUB 8 I912 SHEET 3 [IF 5 Phone Phone 5a 160 c Compound Temperatu re 50 p0 Compound Temperafure O 50 I00 C Temperarure Phone Phone Y 0 5O 1 C Tem pera T u re [X I 'EXTORS O 50 I00 C Temperature o mm 8 K rm w H mo MOM S KN R RU V HYHYW PATENTEDAus 8 I972 SHEET U BF 5 F/ Phone 9 3O 3 Temperorure O 50 iOC c Temperofure INVENTORS Hmovosm AYANO YAsuAKa Kasmo Hmovosm SATO YUKIHIKO OHTA MmoRu FUKUHARA PATENTED'Auc 8 I972 SHEET 5 BF 5 COMPOUND FOR ELECTRIC DEVICES This application is a continuationin-part of our copending application Ser. No. 626,751 filed Mar. 29, 1967, now abandoned.

INTRODUCTION This invention relates generally to the reduction of hum or other noises originating from magnetic actions occurring in the core-and-coil elements of electrical devices. It particularly concerns the reduction of such noises in the ballast elements of discharge lamps.

The term transformer hum" originated from noises emitted from the core-and-coil elements of transformers or other electrical devices although it is characteristic of all electrical devices whose mechanisms include in part, a core-and-coil element. Such undesirable noises result from vibrational energy induced by electromagnetic forces inherent in the core-and-coil elements.

Discharge lamps containing ballasts are typical examples of such electrical devices. A discharge lamp may generally be defined as a lamp containing a low pressure gas or vapor which ionizes and emits light when an electric discharge occurs. Fluorescent materials are sometimes used on the inside of the glass envelope to increase the illumination, as in an ordinary fluorescent lamp.

Discharge lamp ballasts mainly consist of a core-andcoil element typically comprising a coil of copper wire wound on a core of thin iron stampings. The two main functions of such ballasts are to give the high-voltage inductive kick necessary to start the lamp when the current passing through the lamp is interrupted, and to maintain the current through the lamp within the proper range once the lamp is started. Ballasts are designed for the particular wattage and voltage of the lamp in which they are to be used.

Noise or transformer hum from such ballasts is caused by vibration due to the magnetic action in the ballast core-and-coil element and is aggravated when the vibrations are transmitted to the supporting frame of the metallic panel. Noise is generally generated by magnetostrictive changes in the dimensions of the core, by vibration of the core, and by stray magnetic fields causing vibration of the ballast case or even of the fitting in which the ballast is mounted.

When discharge lamp fixtures are used in factories,

large stores and other places where a fairly high noise level continuously exists, the noises produced by their ballasts are not of primary importance. However, when discharge lamps are installed in quiet locations, such as hospitals, libraries, offices and living rooms, even slight noises can be bothersome and annoying. Solutions for reducing such noises are constantly being sought. One suggested solution has called for a more efiicient mounting of the ballast on soft rubber or placing some similar non-rigid material between the ballast and the metallic mounting. While some of the noise can be eliminated by proper mounting, the noise level emitted still remains objectionable for many purposes.

Another solution has called for encasing the ballast within a resinous compound. However this solution reduces noise only in certain limited temperature intervals within the operating temperature range of the ballast. Typically, the operating temperature range of a ballast will vary from about C. to about 130 C.

Within this temperature range it is typical to find ballast starting temperatures of about 0 C. to about 30 C. and stabilization temperatures of about to about 1 30 C.

The auditory sense is very conscious of noise emitted when a lamp is first turned on due to the abrupt interruption in the relatively noise-free environment. The auditory sense also becomes very sensitive to noise emitted by discharge lamps after their stabilization due to annoyingly continuous repetitious sound. The time period between such starting and stabilization temperatures is very short. Therefore, any noise existing therebetween is of little significance in terms of a nuisance value. Consequently while all of the listed proposed solutions are somewhat effective, ballast noise annoyingly remains.

It is therefore an object of this invention to provide an electrical device containing a core-and-coil element which is substantially free of transformer hum or other noises derived from the magnetic action of coreand-coil elements.

In one of its specific applications, it is an object of this invention to provide a discharge lamp fixture which is substantially free from ballast noise.

With more particularity, it is also an object of this invention to substantially reduce ballast noise associated with discharge lamps during that period of time when it is most annoying to auditory sensitivity, i.e., upon starting the discharge lamp and after the discharge lamp has stabilized.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:

FIG. 1 is a graph showing loss factor as a function of compound temperature for illustrative thermoplastic and therrnosetting resins.

FIG. 2 is a graph showing loss factor as a function of compound temperature for an illustrative organic mixture typical of this invention.

FIG. 3 is a graph showing loss factor as a function of compound temperature for an organic combination comprising an unsaturated polyester resin and a polyurethane.

FIG. 4 is a graph showing loss factor as a function of compound temperature for an organic combination comprising an unsaturated polyester and an asphalt.

FIG. 5 is a graph showing noise level as a function of compound temperature for a polyurethane.

FIG. 6 is a graph showing noise level as a function of compound temperature for pitch.

FIG. 7 is a graph showing noise level as a function of compound temperature for an unsaturated polyester resin.

FIG. 8 is a graph showing the relationship between noise and the d loss factor.

FIG. 9 is a graph showing noise level as a function of compound temperature for an organic combination comprising an unsaturated polyester and a polyurethane.

FIG. 10 is a graph showing noise level as a function of compound temperature for an organic combination comprising an unsaturated polyester and a blown asphalt.

FIG. 11 is a graph showing noise level as a function of compound temperature for an organic combination comprising an unsaturated polyester and a polyurethane.

FIG. 12 is a graph showing noise level as a function of compound temperature for an organic combination comprising an unsaturated polyester and a polyurethane.

FIG. 13 is a graph showing noise level as a function of compound temperature for an organic combination comprising an unsaturated polyester and a polyurethane.

FIG. 14 is a graph showing noise level as a function of compound temperature for an organic combination comprising an unsaturated polyester and a polyurethane.

' FIG. 15 is a graph showing noise level as a function of compound temperature for an organic combination comprising an unsaturated polyester and a blown asphalt.

FIG. 16 is a graph showing noise level as a function of compound temperature for an organic combination comprising an unsaturated polyester and a straight asphalt.

FIG. 17 is a graph showing noise level as a function of compound temperature for an organic compound combination comprising an unsaturated polyester and gilsonite.

FIG. 18 is a graph showing noise level as a function of compound temperature for an organic combination comprising an unsaturated polyester and a blown asphalt.

FIG. 19 is a graph showing noise level as a function of compound temperature for an unsaturated polyester.

FIG. 20 is a perspective view of a contained coreand-coil element being charged with a resinous mixture.

FIG. 21 shows a cross sectional view of an electrical device containing a core-and-coil element, charged with a uniform resinous mixture.

FIG. 22 is a perspective view of a dissassembled electrical device containing a core-and-coil element encased within separately molded resinous plates.

While the invention will be described in connection with a preferred embodiment, it will be understood that we do not intend to limit the invention to that embodiment. On the contrary, we intend to cover all altematives, modifications and equivalents as may be included within the spirit and scope of the invention.

As noted above the prior art has shown the use of single resinous compounds to encase ballast core-and-coil elements in order to reduce noise. However, as further indicated above such a use was far from being totally effective in reducing noise. Noise reduction took place only within certain temperature intervals of the ballast operating temperature range which varies from about 0 C. to about 130 C. Furthermore, adding to the total ineffectiveness in using these single resinous compounds is the sometimes low degree of sound reduction in the temperature interval where noise is reduced. Consequently, noise may be reduced at either starting temperatures of about 0 C. to about C. or at stabilization temperatures of about 70 C. to about 130 C. and even then, such reduction may be ineffective due to its low degree. However, effective noise reduction at starting and stabilization temperatures does not take place. This is a definite shortcoming since it is at these temperatures that noise is most bothersome as noted above.

We have discovered the reason for this partial and sometimes ineffective noise reduction. The reason may be explained by first referring to FIG. 1 which shows d loss factor values which will be defined below for two different organic compounds as a function of temperature. Curve A associated with a thermoplastic resin shows a maximum d loss factor value at about 20 C. and Curve B associated with a therrnosetting resin shows a high d loss factor value at about 130 C. It has been discovered that d loss factor values for a given organic compound may be employed as a measure of the conversion ratio of vibrational energy to heat energy. Therefore, as d increases a larger proportionate amount of vibrational energy is dissipated in the form of heat energy and consequently a smaller amount of vibrational energy is transmitted through the organic compound. While the use of the therrnosetting compound as an encasing compound will reduce noise at stabilization temperatures of about 70-130 C. due to its high d loss factor values at such temperatures, it will not eflectively reduce noise at starting temperatures of about 030 C. due to its low d loss factor values at such temperatures; and consequently there will be a small conversion of vibrational energy to heat energy at such starting temperatures. Similarly, while the thermoplastic compound will reduce noise at starting temperatures of about 0-30 C., it will not effectively reduce noise at stabilization temperatures of about 70-130 C, due to its low d loss factor value at the stabilization temperatures. Consequently, neither compound will effectivelyreduce noises at both starting and' stabilization temperatures. Furthermore, if the magnitude of the d loss factor values is too low there will be a low degree of conversion of vibrational energy to heat energy.

The prior art in failing to appreciate the correlation between d loss factor values and noise reductions is not aware of the limiting effect of d loss factor values in using only one encasing organic compound and the degree of sound reduction as affected by d loss factor values.

In order to illustrate the effect of using single compounds in reducing noise of a sequence ballast for two 40 watt fluorescent lamps, three ballasts for such fluorescent lamps were charged with polyurethane, pitch, and unsaturated polyester, respectively. The polyurethane resin was mixed with quartz sand. The d loss factor values for polyurethane, pitch, and an unsaturated polyester at 0 C., room temperature, and C. are given in Table I.

TABLE I d loss factor values Organic Compounds 0C Room Temp. 100C polyurethane 0.13 0.10 0.05 pitch 0.08 0.10 0.05 unsaturated polyester 0.04 0.06 0.07

resin After the ballasts had been charged with these organic compounds, noises emitted therefrom were measured as a function of organic compound temperature with a precision noise meter, placed 2 meters from the ballast. The results are given in FIGS. 5, 6, and 7, respectively. FIG. 5 shows that noise reduction was initially efiective at starting temperatures but as the temperature of the compound rose, noises increased. FIG. 6 shows efiective noise reduction at starting temperatures but as the compound temperatures increased, so did noise. FIG. 7 shows effective noise reduction at stabilization temperatures but high noise levels at starting temperatures.

Noise versus temperature relationships for FIGS. 5, 6, and 7 at temperatures of 0 C., room temperature and 100 C. are given below in Table II.

TABLE II Noise level in phons Organic Compound 0C Room Temp. 100C polyurethane 8 l0 1 9 pitch 12 16 unsaturated polyester 1 8 l 6 l 2 In comparing Tables I and II it is noted that large d loss factor values are related to more effective noise reduction.

In accordance with this invention, sound emission from core-and-coil elements of electrical devices is effectively reduced by disposing a material comprising the combination of first and second organic members around the core-and-coil element such that it is substantially encased by the material. The first organic member must have a maximum d loss factor value, preferably greater than about 0.06, over the temperature range of about 0 C. to about 130 C., in the starting temperature interval of the core-and-coil element. Similarly, the second organic member must have a maximum d loss factor value, preferably greater than 0.06, over the temperature range of about 0 C. to about 130 C., in the stabilized temperature interval of the core-and-coil element. Consequently, the material comprising the first and second organic members will have a maximum d loss factor value over the temperature range of about 0 C. to about 130 C. in the starting and stabilization temperature intervals. The overall effect produced by the prepared material when it is applied as an encasing agent of core-and-coil elements is to effectively reduce noise over the temperature intervals where the human auditory sense is most perceptive.

As just noted the d loss factor values for the organic compounds constituting the organic compound combination are preferably greater than about 0.06. This value was arrived at by first determining the noise level generated by the core-and-coil element of discharge lamps, which is annoying to the users of such lamps when installed in such locations as general ofiices, libraries and the like. The majority of users became particularly annoyed at noise levels of 16 phons or more. Being aware of this value experiments were conducted in which three different organic compounds having known varying d loss factor values were respectively placed within the ballasts of three lighting fixtures, each having two 40-watt fluorescent lamps whose source voltages and frequencies were 100 volts and 60 cps respectively. The noise levels generated by each of the three lamps were plotted respectively against the corresponding d loss factor values associated with the organic compound placed in the ballast of each lamp. The mean values for these tests are given in FIG. 8 where it should be noted that d loss factor values necessary to effectively dampen noise levels to values below 16 phons should be greater than about 0.06.

This invention stems in pan from the discovery that d loss factor values are a measure of the conversion of vibrational energy to heat energy. At this point in order to more clearly define the d loss factor value, reference is made to various well known stress-strain deformation equations. Generally, in the static deformation of an elastic material within the elastic limit, the stress applied to the elastic material is proportional to the strain as given by:

wherein ais stress, 6 is strain and E is a modulus of elasticity generally referred to as Youngs Modulus. In kinetic deformation the stress varies periodically, usually with a sinusoidal alternation, at a frequency v in cycles/secs or w =21rv radians/secs. The strain alternates but is out of phase with the stress. The stress can be decomposed vectorially into two components, one in phase with the strain and one out of phase with the strain. When these vectors are divided by the strain, the modulus, given as E, is separated into an in (real) and out-of-phase (imaginary) component given by:

wherein j is the imaginary unit T and d referred to herein as the d loss factor value is the tangent value of the phase angle 8 which is a dimensionless parameter conveying no physical magnitude, but rather a measure of the ratio of energy loss to energy stored in a cyclic formation. It has been discovered that this relationship can also be stated as a measure of the conversion ratio of the vibrational energy to the heat energy.

The d loss factor value for a given compound may be determined by specifically designed commercially available equipment. The basic apparatus used in determining the reported d loss factor values of this invention is identified as the Complex Modulus Apparatus 3930 manufactured by Briiel and Kjaer of Naerum, Denmark. Instructions and basic specifications for utilizing the Complex Modulus Apparatus in obtaining d loss factor values may be found in an operation manual published by the manufacturer entitled Instructions and Applications, Complex Modulus Apparatus Type 3930, dated 1964, the disclosures of which are included herein by reference.

Referring to FIG. 2 there is shown the (1 loss factor value as function of temperature for an organic mixture typical of that used in this invention. It should be noted that the organic compound combination exhibits high d loss factor values at both starting and stabilization temperature intervals, i.e., at about 0l30 C. and l 30 C. respectively. With such a combination effective sound reduction will exist at both starting and stabilization temperatures of the core-and-coil elements of electrical devices.

In order to illustrate the effect of employing the organic mixture of this invention, as opposed to employing a single organic compound, the ballast elements for each of five different two 40-watt fluorescent lamps measured at temperatures of C., 20 C., 60 C. and

l00 C. in the same manner described above. The results are given in Table III.

TABLE III Organic Sample Noise level in phons Compound No. 0C 20C 60C l00C unsaturated l 15 l 1 l4 l2 polyester 2 l5 14 l 3 l 3 3 l3 7 8 l l 4 9 7 7 7 5 22 21 mean I5 I l l2 l3 urethane l 8 7 26 35 rubber 2 7 9 26 37 3 6 9 27 37 4 6 6 30 37 5 7 7 28 37 mean 7 8 27 37 unsaturated 1 l0 l2 l5 l l polyester plus 2 l3 l4 17 l l urethane 3 l l l0 l2 l0 rubber 4 7 9 9 6 5 7 7 7 9 mean l0 l0 l2 9 7 It can be seen from Table III that the noise level in the lamps using the combination of materials was reduced throughout the temperature range 0 C. to 100 C., while the noise level in the lamps employing the individual organic compounds was efiectively reduced only within those portions of the temperature ranges where they have sufficiently high d loss factor values.

Among the preferred organic compounds exhibiting high d loss factor values sufficient to effectively reduce core-and-coil noise at stabilization temperatures are unsaturated polyester resins, and most preferably those unsaturated polyester resins which have d loss factor values greater than about 0.06 at temperatures equivalent to stabilization temperatures of the coreand-coil elements they are to encase.

The preparation of unsaturated polyesters is generally well known in the art. They are typically prepared by reacting an unsaturated polybasic acid with a polyhydric alcohol. Unsaturated polybasic acids particularly suitable in preparing the unsaturated polyester resins employed in this invention are maleic anhydride, adipic acid, succinic acid and phthalic acid. Particularly suitable polyhydric alcohols are ethylene glycol, diethylene glycol and propylene glycol. Once the polyester has been formed, a vinyl monomer such as vinyl tolylene, divinyl benzene, or styrene may be added as a cross linking agent and thereby copolymerize with the unsaturated polyester.

In many instances it is necessary to solidify the unsaturated polyester prior to its use. This may be accomplished by the addition of a setting catalystto the unsaturated polyester. Such a catalyst may be, for example, methyl ethyl ketone peroxide, benzoyl peroxide or a mixture of one of the listed peroxide catalysts with either dimethyl aniline or diethyl aniline.

' In order to illustrate the preparation of typical polyesters which may be employed in the present invention, the following illustrative examples are given:

EXAMPLE A A reaction mixture comprising i.0 moles of maleic anhydride 1.0 moles of phthalic anhydride and 2.2 moles of diethylene glycol was reacted in carbonic acid gas flow at -l20 C. for 9 hours. An unsaturated polyester of oxidation No. 3.1 was obtained. Six hundred and thirty grams of this unsaturated polyester were dissolved in 470 grams of styrene together with 150 milligrams of hydroquinone. A cross linked unsaturated polyester was obtained.

EXAMPLE B A reaction mixture comprising 1.3 moles of maleic anhydric 0.7 moles of adipic acid, and 2.2 moles of propylene glycol was reacted in a carbonic acid gas flow at l70220 C. for 8 hours. The mixture was further reacted for 1 hour at 220 C. under a reduced pressure of 150 mm. Hg. An unsaturated polyester of oxidation No. 8.6 was obtained. This polyester was dissolved in styrene containing 220 ppm of hydroquinone. A cross linked, unsaturated polyester containing 40 percent styrene was obtained.

EXAMPLE C A reaction mixture comprising 1.0 moles of phthalic anhydride 1.0 moles of adipic acid, 2.2 moles of diethylene glycol, and 2.2 moles of ethylene glycol was reacted in a carbonic acid gas flow at 160-205 C. for 7 hours. An unsaturated polyester resin having an oxidation No. of 6.4 was obtained. The unsaturated polyester was cooled to 100 C. Subsequent to cooling, 1 mole of maleic anhydride and 170 milligrams of hydroquinone were added. This mixture was reacted for 6 hours at a temperature of l220 C. and then for 1 hour at 220 C. under a reduced pressure of mm. Hg. The resulting unsaturated polyester had an oxidation No. of 10.1. This polyester was then cooled to C. Styrene was added thereto so as to produce a cross-linked unsaturated polyester resin containing 40 percent styrene.

Among the preferred organic materials exhibiting high d loss factor values sufiicient to effectively reduce core-and-coil noise at starting temperatures are polyurethane resins, asphalts, oils and fats. Most preferred are polyurethane resins, asphalts, oils and fats which have d loss factor values greater than about 0.06 at temperatures equivalent to the starting temperatures of the core-and-coil elements they will encase.

The chemistry of polyurethanes, including their preparation, is generally well known as given in High Polymers Vol. XVI, PolyurethanezChemistry and Technology, Saunders and Frisch, Interscience Publishers, 1963 which is included herein by reference. However, very briefly stated, polyurethane resins typically used in preparing the organic mixture of this invention may be produced by the reaction of di-or polyfunctional hydroxyl compounds with di-or polyfunctional isocyanates. l-lydroxyl terminated polyesters of polyethers and more specifically polyols such as castor oil, glycerine or pentaerythritol are some examples of the polyfunctional hydroxyl compounds. The isocyanates normally used are the diisocyanates which are typically mixtures of tolylene diisocyanate isomers. Cross-linked polymers having repeated urethane or urethane derived linkages may also be used. It may be necessary to solidify the polyurethanes prior to their use, and this may be accomplished by the addition of a setting catalyst to the polyurethane. Typical examples of setting catalysts are N, N, N, N'- tetramethyl-l.3butanediamine and dimethyl ethanolamine.

Among the asphalts which exhibit high d loss factor values sufficient to reduce the noise of core-and-coil elements at starting temperatures are natural blown asphalt, petroleum asphalt and gilsonite. Typical oils and fats which exhibit high d loss factor values sufficient to reduce the noise of core-and-coil elements at starting temperatures are tung oil, linseed oil, cuttlefish oil, rape oil and the like. 7

The organic compound mixture or combination may be used in any of a number of different physical forms. For example, it may vary from a substantially homogeneous mixture of two organic compounds to a two-plate assembly in a face-to-face relationship where the first plate comprises the organic compound having high d loss factor values at starting temperatures and the second plate comprises the organic compound having high d loss factor values at stabilization temperatures.

In a substantially homogeneous mixture, the proportionate amount of the first and second organic members will vary with the particular organic mixture being prepared. However, such proportionate amounts will normally vary, on a 100 parts by weight basis, from about 25 to about 99 parts, preferably about 50-90 parts, of organic compound having high d loss factor values at stabilization temperatures, and from about 1 I to about 75 parts, preferably about 10-50 parts, of organic compound having high d loss factor values at starting temperatures. For example the optimum mixing ratio for unsaturated polyester resin and asphalt is 10 to 99 parts by weight of the former to 30 parts by weight of the latter.

Inorganic fillers such as calcium carbonate, clay, quartz, sand, silica powder or combinations thereof are preferably added to the organic mixtures of this invention in amounts equal to about 40 to about 80 percent as based on the total weight of the organic members responsible for noise reduction. Such fillers to not influence the d loss factor values.

As an added safety feature provided to prevent electrical fires ignited from the excessive heat generated by voltage overload, it is desirable to include an inorganic salt or salts having water of crystallization in the organic combination. By using such inorganic salts the danger from electrical fires arising from voltage overload in the core-and-coil element of an electrical device is greatly reduced. As the temperature of the core-and-coil' element increases, the inorganic salt discharges its water of crystallization in the form of water vapor; consequently, the probability of excessive heat generation is reduced due to the removal of heat by the vaporization of the water of crystallization. However, it is necessary to select an inorganic salt whose water of crystallization will not discharge in the form of water vapor prematurely due to the heat generated during a setting reaction. If the water of crystallization is removed prematurely, there will be none remaining to remove dangerous heat build-up in the event of voltage overload. Furthermore, excessive use of inorganic hydrated salts such as chloride salts may influence catalytic action and thereby adversely affect the setting of the organic compound(s). These salts are preferably used in amounts of about 10 to about 40 percent by weight as based on the total weight of the organic members responsible for noise reduction.

Some suitable inorganic salts having water of crystal lization are the following:

Ca0 8H O discharging water of crystallization at C. SiO; 8H O discharging water of crystallization at BaO 8H O discharging water of crystallization at SnCl 8H O discharging water of crystallization at BaCl 2H O discharging water of crystallization at CuSO, 3H O discharging water of crystallization at to C.

A1 0 31-1 0 discharging water of crystallization at If the mixture is to be uniformly mixed, certain ingredient combinations require additional preparative steps. For example, it is difficult to uniformly disperse and mix asphalt with the other ingredients. Consequently, asphalt is first dissolved in a part or all of the monomer solvent of the unsaturated polyester resin. The asphalt-monomer solution is then mixed with the remainder of the ingredients so that a uniform organic mixture is produced.

In preparing the organic mixtures of this invention care must be taken to always check the d loss factor value after its preparation. It has been discovered that the final organic mixture does not necessarily cumulatively inherit the d loss factor values of the individual organic compounds constituting the mixture.

The mixtures of this invention may be easily added to a case containing a core-and-coil element. FIG. 20 shows a transformer 3 and a condenser 4 contained within a case 2 covered with a lid 1 being encased within an organic mixture 5 of this invention by pouring the mixture 5 from a mixture tank 6 into the case 2. The organic mixture 5 is shown as being poured in a dry state. When the mixture 5 is added in the dry state the ingredients must be carefully chosen to ensure mixture fluidity. For example the use of excessive amounts of silica will reduce fluidity as will certain organic compounds such as epoxy urethane rubber. However, the mixture 5 may be added to the case 2 in a wet state if the setting catalysts are added to the mixture while it is in the case 2; this procedure insures that'the organic mixture will completely fill all the void space within the case 2 and removes mixture fluidity considerations.

FIG. 21 illustrates the completed electrical transformer assembly prepared by the process illustrated in FIG. 20, including a transformer core-and-coil element 3 which is completely encased within the organic mixture 5 of this invention.

As previously noted, the organic compound mixture of this invention may also take the form of a two-plate assembly. Wherein the material comprising the combination of the first and second organic members is in the form of plate assemblies comprising at least two plates in a face-to-face relationship. The first plate comprises the first organic member defined above; the second plate comprises the second organic member also defined above. The plate assemblies are disposed around the core-and-coil element of said electric device by placing at least one of them along each side of the core-and-coil element. FIG. 22 shows six plate assemblies 8, 9, 10, ll, 12 and 13 each being made up of a pair of separate plates 6 and 7 in face-to-face relationship. The plates 6 and 7 may be either separable or permanently attached to one another. Plate 6 comprises an organic material possessing a high d loss factor value at starting temperatures, while plate 7 comprises an organic material possessing a high d loss factor value at stabilization temperatures. The six plate assemblies 8, 9, 10, 11, 12 and 13 are constructed to fit snugly between the sides, lid and bottom of the case 2, and the sides, top and bottom, respectively, of the transformer 3 so that the transformer 3 is completely encased by the assemblies 8, 9, 10, ll, 12 and 13 after they are positioned in the case 2.

The use of the two-plate assemblies provides several advantageous features. For instance, since the organic compounds are molded into plates a large amount of inorganic filler substance such as silica powder can be mixed with the organic compound without being limited by fluidity considerations of the final composition since as noted above excessive amounts of silica in a mixture will reduce its fluidity. The plate construction also permits the use of organic compounds having a low fluidity. These compounds could not otherwise be used since their low fluidity would prevent efficient encasement of a core-and-coil element when the organic combination is added to a transformer case in the form of a uniform mixture. An example of a low-fluidity organic compound is epoxy urethane rubber. Yet another feature of this embodiment is that it facilitates the use of organic compounds which are difficult to set when in combination with other organic compounds. For example, by using separately constructed plates and unsaturated polyester and tung oil may be used in combination. Furthermore, in some cases the setting catalysts or promoters for two different resins have reciprocal actions on one another, such as competitive reactions, and/or have different setting velocities thereby preventing their combined use. All of the above problems may be avoided by separately molding the combined organic compounds in the form of plates.

The following examples are given to illustrate the manner of practicing our invention only and should not be considered or interpreted in any way to restrict this invention. All parts given in the following examples are on a weight basis:

EXAMPLE I One hundred parts of unsaturated polyester resin, 20 parts of polyol having a hydroxyl value of 500, 20 parts of tolylene diisocyanate and 0.5 parts of a 6 percent cobalt napthenate solution were mixed together. Subsequent to mixing, 0.5 parts of dimethylethanol amine were added and mixed. To this mixture was added l part of methyl ethyl ketone peroxide once again followed with mixing. Subsequent to mixing, 200 parts of No. 6 silica sand and parts of 5 p. silica powder were also added and mixed. This final mixture was placed in a ballast for two 40-watt fluorescent lamps and was heated at 50 C. for 1 hour in order to promote setting.

The relationship between the d loss factor value and temperature for this particular encasing organic combination is shown in FIG. 3. The maximum d loss factor value resulting from the urethane ingredient appears at about 0 C. and the largest d loss factor value resulting from the unsaturated polyester appears at about 100 C.

EXAMPLE II Fifty parts blown asphalt were dissolved in 50 parts of styrene. To this mixture was added 100 parts of unsaturated polyester resin, 1 part of a 6 percent cobalt napthenate solution and one part of methyl ethyl ketone peroxide. The resulting mixture was well stirred and placed into a ballast for a 400-watt mercury lamp and was left standing at 60 C. for 1.5 hours to permit it to set. The relationship between the d loss factor value and the temperature for this particular organic compound combination is shown in FIG. 4. It should be noted that the largest value resulting from the blown asphalt appears at about 0 C. and the largest d loss factor value resulting from the unsaturated polyester appears at about 100 C.

EXAMPLE III Eighty parts of unsaturated polyester containing 40 percent by weightstyrene, 10 parts of a polyol having a hydroxyl value of 500, 9 parts of tolylene diisocyanate, 1 part of benzoyl peroxide and 300 parts of silica powder ranging from to 200 mesh, were mixed together. The mixture was heated at 60 C. for 30 minutes so that it would set. A ballast for two 40-watt fluorescent lamps was charged with this mixture. The lamps were lit and noises emitted from the ballast were measured as a function of compound temperature at a 2 meter distance from the ballast with a precision noise meter. The results as given in FIG. 9 show effective noise reduction to levels varying from about 9 to ll phons throughout the operating temperatures of the ballast corresponding to encasing organic compound combination temperatures of about 0 to 100 C.

EXAMPLE IV A mixture comprising 90 parts of unsaturated polyester in a 55 percent by weight styrene solution, 10 parts of blown asphalt, 2 parts of methyl ethyl ketone peroxide in 60 percent by weight dimethyl phthalate, 1

part of cobalt napthenate and 250 parts of calcium carbonate powder of 200 mesh, was heated at 90 C. for 40 minutes so that it could set. A sequence ballast for two 40-watt fluorescent lamps was charged with the mixture. The lamps were lit and noises emitted from the ballast were measured as a function of compound temperature at a 2 meter distance from the ballast with a precision noise meter. The results given in FIG. 10 show effective noise reduction to levels varying from about 9 to l l phons throughout the operating temperatures of the ballast corresponding to the encasing organic compound combination temperatures of about to 100 C.

EXAMPLE V mixture and noises were measured (with a precision noise meter) as a function of compound temperature at a 2 meter distance from the ballast after the lamps were turned on. The results given in FIG. 11 show effective noise reduction to levels varying from about 9 to about 12 phons throughout the operating temperatures of the ballast corresponding to encasing organic compound combination temperatures of about 0 to 100 C EXAMPLE VI Two-hundred and fifty parts of silica powder (100-250 mesh) were mixed with 100 parts of a mixture prepared by mixing 75 parts of unsaturated polyester resin, 15 parts of polyether resin having a molecular weight of 500, 10 parts of tolylene diisocyanate, 0.1 parts of dimethyl aniline and 1.5 parts of benzoyl peroxide. The mixture was placed in a ballast for a 250-watt mercury lamp and was heated at 60 C. for 30 minutes so that it would set. The lamp was lit and noises emitted from the ballasts were measured as a function of compound temperature at a 2 meter distance from the ballast with a precision noise meter. The results given in FIG. 12 show noise reduction at slightly higher noise levels varying between and phons over the operating temperatures of the ballast corresponding to the encasing compound combination temperatures of about 0 to 100 C. While these noise levels are slightly higher than the others noted, noises were reduced to a non-annoying level.

Three-hundred and fifty parts of silica powder (100-250 mesh) were mixed with 100 parts of a mixture prepared by mixing 40 parts of unsaturated polyester, 50 parts of castor oil, 10 parts of tolylene diisocyanate, one part of benzoyl peroxide and one-fifteenth parts of dimethyl aniline. The mixture was placed in a 40-watt sequence ballast for two fluorescent lamps and was heated at 50 C. for 60 minutes so that it would set. The lamps were lit and noises emitted from the encased ballast were measured as a function of compound temperature at a 2 meter distance from the ballast with a precision noise meter. The results given in FIG. 13 shows noise reduction to levels varying from about 13 to 15 phons over the operating temperatures of the ballast corresponding to encasing organic compound combination temperatures of about 0 to 100 C.

EXAMPLE vm Two-hundred and seventy parts of silica powder (l00-250 mesh) were mixed with 100 parts of a mixture prepared by mixing parts of unsaturated polyester containing 55 percent by weight styrene, 5 parts of polyol having a molecular weight of 500, 5 parts of tolylene diisocyanate, 1.5 parts of benzoyl peroxide and 0.2 parts of diethyl aniline. This mixture was placed into a sequence ballast for two 40-watt fluorescent lamps and was heated at 20 C. for 2 hours so that it would set. The lamps were lit and noises emitted from the encased ballast were measured as a function of compound temperature at a 2 meter distance from the ballast with a precision noise meter. The results given in FIG. 14 show eflective noise reduction to levels varying from about 15 to 16 phons over the operating temperatures of the ballast corresponding to encasing organic compound combination temperatures of about 0 to C.

EXAMPLE IX Seventy parts of unsaturated polyester, 20 parts of castor oil, 10 parts of tolylene diisocyanate, 1.5 parts of benzoyl peroxide, 0.2 parts of dimethyl aniline, parts of A1 0 having an average diameter of 20 p. and 180 parts of quartz sand were mixed and subjected to a temperature of 55 C.; the mixture set. A relatively inflammable encasing mixture was produced.

EXAMPLE X Eighty-four parts of unsaturated polyester resin and 2 parts of benzoyl peroxide were added and mixed to 26 parts of a solution prepared by mixing 12 parts of blown asphalt and 55 parts of styrene. To this mixture was added 250 parts of a mixture comprising calcium carbonate and glass fibers in a 5:1 weight ratio. The resulting mixture was placed in a ballast for two 40- watt fluorescent lamps and was left standing at 60 C. for 40 minutes to be set. The fluorescent lamps were lit and noises emitted from the encased ballast were measured as a function of the compound temperature two meters from the ballast with a precision noise meter. The results given in FIG. 15 show noise reduction to levels varying from about 14 to about 18 phons over the operating temperatures of the ballast corresponding to encasing organic compound temperatures of about 0 to 100C. 4

EXAMPLE Xl Thirty parts of a solution prepared by mixing 50 parts of straight asphalt and 50 parts of styrene were added and mixed to a mixture containing 100 parts of unsaturated polyester resin, 0.5 parts of diethyl aniline and 2 parts of benzoyl peroxide. To this mixture was added parts of No. 6 silica sand and 100 parts of clay. The resulting mixture was placed in a sequence ballast for two 40-watt fluorescent lamps and heated at 60 C. for 1 hour. Subsequent to setting, the fluorescent lamps were lit and noises emitted from the ballast were measured as a function of compound temperature 2 meters from the ballast with a precision noise meter. The results given in FIG. 16 show effective noise reduction to levels varying from about 8 to 9 phons over the operating temperatures of the ballast corresponding to EXAMPLE XII One hundred parts of unsaturated polyester resin containing 30 percent by weight styrene were added to 50 parts of a solution prepared by dissolving 30 parts of gilsonite in 70 parts of styrene. To this mixture was added 200 parts of No. 6 silica sand and 150 parts of silica powder followed with mixing. One part of cobalt napthanate, 0.3 parts of dimethyl aniline 0.3 parts of methyl aniline and 1.5 parts of methyl ethyl ketone peroxide were then added to the mixture. The final mixture was placed in a ballast for two 40-watt fluorescent lamps and left standing at 50 C. for 1.5 hours to be set. The fluorescent lamps were lit and noises emitted from the ballast were measured as a function of compound temperature 2 meters from the ballast with a precision noise meter. The results given in FIG. 17 show effective noise reduction to levels of about 8 to 12 phons over the operating temperatures of the ballast corresponding to encasing organic compound temperatures of about to 100 C.

EXAMPLE XIII Fifteen parts of a solution prepared by dissolving 40 parts of blown asphalt in 60 parts of styrene were mixed with 85 parts of unsaturated polyester resin and 1.8 parts of benzoyl peroxide. To this mixture was added 200 parts of silica powder and 100 parts of aluminum hydroxide followed with stirring. This final mixture was placed in ten sequence ballasts each ballast being for two 40-watt fluorescent lamps. The charged ballasts were left standing at 60 C. for 1 hour to be set. The lamps were lit and noises emitted from the ballast were measured as a function of compound temperature 2 meters from the ballast with a precision noise meter. The results given in FIG. 18 show effective noise reduction varying from about 15 to 20 phons over the operating temperature of the ballast corresponding to encasing organic combination temperatures of about 0 to 100 C. In addition to determining the noise-temperature characteristics of this particular composition, the fluorescent lamps were subjected to a source voltage 150 percent over their rating. Even with this voltage overload none of the organic combinations started on fire.

COMPARATIVE TEST In order to determine the noise reduction properties of the combination prepared in Example XIII without any blown asphalt, 85 parts of unsaturated polyester and 1.8 parts of benzoyl peroxide wereadded and mixed with parts of styrene. Also, in order to determine the affect of hydrated aluminum hydroxide in with a precision noise meter. The results given in FIG. 19 show only partial effective noise reduction since noise reduction at low organic compound combination temperatures in the 0 C. vicinity is about 27 phons.

Furthermore, when this composition was subjected to a voltage 150 percent over its rating the winding or coil within the ballast burned and broke in five out of the 10 lamps lit after only 20 minutes indicating the advantageous safety properties given an organic encasing combination by adding a salt containing water of crystallization to the organic combination.

EXAMPLE XIV In producing the organic combination in the form of a two-plate assembly, the first plate of the'organic combination responsible for high d loss factor values at starting temperatures was prepared by mixing 100 grams of tung oil, 20 grams of ferric chloride and 500 grams of silica powder. This mixture was then molded into the form of a plate. The plate component responsible for providing high d loss factor values at stabilization temperatures was produced by mixing 100 grams of unsaturated polyester, 1 gram of benzoyl peroxide, 5 grams of diethyl aniline and 600 grams of silica powder and subsequently molding the mixture into the form of a plate.

EXAMPLE XV A plate providing high d loss factor values at starting temperatures was molded from a mixture comprising 100 grams of castor oil, 25 grams of tolylene diisocyanate and 600 grams of silica powder. Similarly, a plate providing high d loss factor values at stabilization temperatures was molded from a mixture comprising 100 grams of unsaturated polyester, one gram of methyl ethyl ketone peroxide, 1 gram of cobalt napthenate and 500 grams of silica powder. The result ing two plates were used in combination to form the two plate assembly of this invention.

In conclusion it should be noted that by practicing this invention it is possible to now effectively reduce preventing fire due to voltage overload, 300 parts of silnoises generated by core-and-coil elements of electric devices, particularly discharge lamp ballasts, to non-annoying levels both at starting and stabilization of such electric devices.

We claim as our invention:

1. In an electric device having a core-and-coil element which generates undesirable noises resulting from vibrational energy induced by electromagnetic forces inherent in said device, a material disposed around said .core-and-coil element for reducing said noises, said material comprising a physical combination of a first organic member selected from the group consisting of polyurethane resins and a second organic member selected from the group consisting of unsaturated polyester resins.

2. The electric device of claim 1 wherein said first organic member contains castor oil as polyol component.

3. The electric device of claim 1 wherein the first organic member has a maximum d loss factor value greater than 0.06 in the starting temperature range of from 0 to 30 C. and the second organic member has a maximum (1 loss factor value greater than 0.06 in the stabilized temperature range of from to C.

combinations thereof, and the inorganic member having water of crystallization is selected from the group consisting of CaO- SH O, SiO 8H O, BaO' 8H O, SnCl- 8H O, BaCl 2H O, CuSO; 3H O and combinations thereof.

* l I I

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4584233 *Dec 12, 1983Apr 22, 1986Chevron Research CompanyPatch for urethane-based membrane and method
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Classifications
U.S. Classification336/96, 524/59, 525/28, 336/100, 528/75, 524/433, 528/50, 524/423, 524/425, 525/49, 524/560, 524/434, 524/436, 524/445
International ClassificationH01F27/02, G10K11/16, H01F27/33, C08L67/06, C08L75/04
Cooperative ClassificationC08L67/06, H01F27/022, C08L75/04, H01F27/33, G10K11/165
European ClassificationG10K11/165, C08L75/04, C08L67/06, H01F27/33, H01F27/02A