DC Buyer's Guide

Application Information

Other Information Information Outline Dimensions Noise, by definition, is unwanted sound as is, therefore, a U^a\ ^U PXa _^[[dcX^] fWXRW \dbc QT ZT_c d]STa R^]ca^[ CWT occupational noise exposure standard promulgated by the Occupational Safety and Health Administration (OSHA) states that “protection against the effects of noise exposure shall be provided when the sound levels exceed those shown in table G-16 of the OSHA standard, when measured on the A scale of a standard sound level meter at slow response.” It is X\_^acP]c c^ ]^cT cWPc cWXb bcP]SPaS P__[XTb c^ cWT f^aZX]V environment and not to any specific device such as an electrical machine. Protection against noise exposure can be handled in three ways: reduction in the level of the noise source, reduction in the transmission of noise, and control of noise at the receiver by protective equipment. BX]RT cWT ]^XbT c^ fWXRW P f^aZTa \Ph QT Tg_^bTS Xb P function of all the noise sources around him/her, as well as the acoustical characteristics of the area, it is impossible, fXcW^dc P STcPX[TS Z]^f[TSVT ^U cWTbT eP[dTb c^ _aTSXRc b^d]S _aTbbdaT [TeT[b ^] cWT f^aZTab{ TPab FWPc Xb PePX[PQ[T Xb \P]dUPRcdaTab{ SPcP cPZT] d]STa R^]ca^[[TS R^]SXcX^]b Power Supplies When DC motors are operated from rectified power supplies, the pulsating voltage and current wave forms affect the motor performance by increasing motor heating and degrading commutating. Because of these effects, it is necessary that the motors be designed or specially selected to suit this type of operation. A motor may, under some conditions, be operated from a power supply different from that indicated on the nameplate. Because the three letters used to identify power supplies in common use have been chosen in alphabetical order of increasing magnitude of ripple current, a motor rated on the basis of an “E” power supply may be operated from a “C” or “D” power supply, and a motor rated on the basis of “D” power supply may be operated from an “C” power supply but not necessarily from an “E” power supply. If it is desired to use a motor rated on the basis of a “C” power supply on either a “D” or “E” power supply, it may be necessary to add an inductance externally to the motor, in order to limit the ripple current to the magnitude implied in the rating. For more information see page 2.29 or contact Wolong . The nameplates of DC motors intended for operation from rectified power supplies will be stamped with a Power Supply Identification as described under POWER SUPPLY IDENTIFI CATION and the external reactance required, if necessary. Audio Noise Modifications Motor Pricing General Information

CWXb SPcP Xb VT]TaP[[h cPZT] Pc ]^ [^PS Pc P b_TRXUXR SXbcP]RT from the source, and is measured in dB’s of sound pressure with a reference pressure of 0.00002 N/m 2 . Another measure of the intensity of the noise which is becoming more accepted is sound power. This is a measure of the intensity of the noise at its source. It is arrived at mathematically through an array of sound pressure readings. The units of sound power are also dB’s with a reference power of 10 12 watts. This number is the noise level of the source and is independent of the surroundings. It can be used to predict resulting sound pressure levels. >UcT] X] cP[ZX]V ^U b^d]S _aTbbdaT fTXVWcX]V ]Tcf^aZb fX[[ be specified. These are sound pressure readings with certain frequencies omitted to more nearly match the frequency aTb_^]bT ^U cWT Wd\P] TPa T V |0} ]Tcf^aZ FWX[T |0} ]Tcf^aZ S1 [TeT[b \Ph QT cWT bP\T U^a cf^ ]^XbT b^daRTb Xc is important to realize that they may sound very different to the ear. The ear is much more sensitive to dB levels of a narrow frequency range. Discreet frequency sources may QT ^QYTRcX^]PQ[T TeT] cW^dVW cWT ^eTaP[[ |0} ]Tcf^aZ S1 level is moderate. Typical values for the Kinamatic line of DP and TEFC frame diameters are given on the following pages. For guaranteed values, refer to Wolong . The values are in sound power and are no [^PS aTPSX]Vb cPZT] dbX]V <6 bTc _^fTa =^XbT [TeT[b Pc Ud[[ load are essentially the same as no load for MG set power.) C^ TbcX\PcT cWT PeTaPVT b^d]S _aTbbdaT |0} ]Tcf^aZ Pc some distance from the machine, use the curve on the following page to obtain the ΔdB to subtract from the sound power value. Blower ventilated motors will generally be quieter than self-ventilated motors. Adding one noise source equal to an existing noise source increases the total sound level 3dB. Although the rectified magnetic noise levels for frames CD210AT-CD320AT never exceed 81 dB(A), rectified noise is in a limited frequency range and may be more objectionable to the ear than “white” noise, which consists of a variety of frequencies. For average sound pressure (Lp) dB(A) of a hemisphere with a 3 ft. radius, subtract 7dB(A). For 6 ft. radius, subtract 13dB(A). For 10 ft. radius, subtract 17dB(A).

Accessories and

Application

5.10

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GEP387-EN 07/19 Prices and data subject to change without notice.