electrical engineering

Insulation Resistance Value Required For Operation

<h3 class="post-title entry-title"><span style="color: #351c75; font-size: medium;"><span style="font-weight: normal;">This post is the third part of </span></span></h3><h3 class="post-title entry-title"><a href="http://hayatei.blogspot.com/2010/12/coil-and-insulation-in-high-voltage_17.html">COIL AND INSULATION IN HIGH VOLTAGE MOTORS</a></h3><h3 class="post-title entry-title"><span style="color: #351c75; font-size: large;"><span style="font-weight: normal;"> The second part  </span></span></h3><h3 class="post-title entry-title" style="font-weight: normal;"><span style="font-size: large;"><a href="http://hayatei.blogspot.com/2010/12/measurement-of-insulation-resistance.html">Measurement Of Insulation Resistance</a></span></h3><h3 class="post-title entry-title" style="font-weight: normal;"><span style="font-size: large;"> </span></h3><h3 class="post-title entry-title" style="background-color: cyan; color: red; font-weight: normal; text-align: center;"><u><span style="font-size: large;"> Insulation Resistance Value Required For Operation</span></u></h3><br />
<br />
<div style="text-align: justify;">In general, it is difficult to give a minimum of permis¬sible insulation resistance value for starting since it varies with the type, rating and size of the motor. However, as a simple standard for daily maintenance, the following equation may be considered for the minimum value.</div><br />
Rm = E + 1<br />
<br />
<span style="background-color: cyan; color: red;">where, </span><br />
<br />
<div style="text-align: justify;"><br />
<span style="background-color: yellow; color: red;">Rm </span>: recommended minimum insulation resistance at 40ºC of the machine winding, in MΩ</div><div style="text-align: justify;"><br />
<span style="background-color: yellow; color: red;">E </span>: Motor rated voltage, in KV</div><br />
<div style="text-align: justify;">When applying the Rm as given by above equation, the temperature correction of measured insulation resistance should be made by use of the following equation if the winding is not at a temperature of 40ºC.</div><div style="text-align: justify;"></div><div class="separator" style="clear: both; text-align: center;"><a href="http://hayatei.blogspot.com/2010/12/insulation-resistance-value-required.html"><img alt="http://img101.herosh.com/2010/12/18/319898224.png" border="0" src="http://img101.herosh.com/2010/12/18/319898224.png" /><span id="goog_1476959027"></span></a><span id="goog_1476959028"></span></div><div style="text-align: center;"></div><div style="text-align: justify;"></div><div style="background-color: yellow; color: red; text-align: center;">where, </div><div style="text-align: justify;"><br />
<span style="background-color: yellow; color: red;">Rc </span>; insulation resistance corrected to 40ºC, in MΩ<br />
<span style="background-color: yellow; color: red;">Rt </span>. measured insulation resistance at a temp. t ,in MΩ <br />
<span style="background-color: yellow; color: red;">A¬0 </span>: insulation resistance correction factor</div><div style="text-align: justify;"><br />
(See Fig. 1-2 Temperature Correction Curve)</div><div style="text-align: justify;"></div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><a href="http://hayatei.blogspot.com/2010/12/insulation-resistance-value-required.html"><img alt="http://img101.herosh.com/2010/12/18/815714691.jpg" src="http://img101.herosh.com/2010/12/18/815714691.jpg" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><br />
</div><div style="background-color: yellow; color: red; text-align: center;"><span style="font-size: large;">Fig.1.2-a Temperature correction curve </span></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><span style="font-size: large;"><a href="http://hayatei.blogspot.com/2010/12/prevention-of-megger-reduction-and.html"><span style="color: black; font-family: Arial;"><span style="background-color: yellow; color: red;"> The 4th part  Prevention Of Megger Reduction .</span></span><span style="background-color: yellow; color: red;"><span style="font-family: Arial;">avaible now</span></span></a></span><br />
<b><span style="color: black; font-family: Arial; font-size: 11pt;"><br />
</span></b><br />
<b><span style="color: black; font-family: Arial; font-size: 11pt;"><br />
</span></b></div><div style="text-align: justify;"></div><div style="text-align: justify;"></div><div style="text-align: justify;"></div>

Insulation Resistance Value Required For Operation

This post is the third part of COIL AND INSULATION IN HIGH VOLTAGE MOTORS The second part Measurement Of Insulation Resistance Insulati...

more information

Measurement Of Insulation Resistance

<div style="text-align: justify;"><h3 class="post-title entry-title"><span style="color: #351c75; font-size: large;"><span style="font-weight: normal;">This post is the second part of </span></span></h3><h3 class="post-title entry-title"><a href="http://hayatei.blogspot.com/2010/12/coil-and-insulation-in-high-voltage_17.html">COIL AND INSULATION IN HIGH VOLTAGE MOTORS</a>  </h3><div style="background-color: magenta; color: yellow; text-align: center;"><u><span style="font-size: large;">Measurement Of Insulation Resistance</span></u></div><div style="color: red;"><br />
</div><div style="color: red;"><br />
</div><div style="color: red;"><span style="font-size: small;">Insulation resistance is the direct current resistance of the insulation which corresponds to leakage current flowing inside and on the surface of the insulation. Decrease in insulation resistance is caused by deterioration or absorption of moisture of the insulation, adhesion of dirt, and temperature rise. The values of insulation resistance obtained by measurement decreases as the test voltage increases and as the duration of the test voltage application is shortened. Since insulation resistance is a useful measure for determining the condition of insulation, it should be measured periodically, while the motor is not in operation, and records of the measuring apparatus used, coil temperature, ambient temperature, relative humidity, and other conditions (for example, the time elapse after motor stoppage) are to be kept.</span></div><div style="color: red;"><span style="font-size: small;"><br />
</span><span style="font-size: small;">The motor, if contaminated, is to be cleaned in the aforementioned manner, the insulating resistance before and after cleaning is to be recorded. Either 500V rotary megger or the-electron tube megger may be used. With a rotary megger, rotate it continuously for at least one minute. With an electron tube megger, apply voltage for 10 minutes. Record insulation resistance values for 30 seconds, 1 minute, and 10 minutes. Recording of time is necessary since insulation resistance varies with the duration of the test because of charge current or absorbed current. Insulation resistance varies with changes in temperature and humidity, but the pressure of salty substance affects the value greatly. If this -happened, consult Mitsubishi Electric Corporation.</span></div><div style="color: red;"><br />
</div><div style="color: red; text-align: center;"><span style="font-size: small;"><span style="font-size: large;"><span style="background-color: yellow; color: red;">To be continued ..... soon</span></span></span></div><div style="color: red;"><br />
</div></div><span style="font-size: small;"><br />
</span>

Measurement Of Insulation Resistance

This post is the second part of COIL AND INSULATION IN HIGH VOLTAGE MOTORS Measurement Of Insulation Resistance Insulation resistance is...

more information

COIL AND INSULATION IN HIGH VOLTAGE MOTORS

<div style="text-align: center;"><u style="color: red;"><span style="font-size: medium;">Inspection And Maintenance</span></u></div><br />
<div style="text-align: justify;">It is desirable that the insulation for the coil of motors is to be carefully kept clean and always dry. Therefore, the ventilating duct and the protective cover are so arranged as to be suitable for each part, and also be designed to reduce containmination, in some case, motor must be heated by means of a space heater to prevent dew drops due to change of motor temperature.</div><br />
<div style="text-align: center;"><span style="font-size: large;"><u style="color: red;">Cleaning Of Coils</u></span></div><br />
<div style="text-align: justify;">Keeping all the insulating materials clean is of much importance. Dust and foreign substances (carbon, copper, power dared mica, etc), in some case, clog the ventilating port, thereby reducing the air flow, and making the dissipation of heat difficult, and thus overheating motors locally or entirely. In case that accumulated fine particles are electrically conductive or produce a conductive pasty adhesive by absorbing water or oil, they finally cause short circuit of coils and earthing troubles; and wearing by fine particles damages insulating materials. It should be noted that the adhesion of oil is not harmful, but cause adhesion and accumulation of various contaminants.</div><div style="text-align: justify;"><br />
</div><div style="background-color: white; text-align: justify;"><br />
</div><div style="background-color: red; color: cyan; text-align: center;"><u><span style="font-size: medium;"><b>METHODS OF CLEANING</b></span></u></div><br />
<div style="text-align: center;"><span style="font-size: small;"><b><span style="color: purple;"><u>Cleaning by wiping with cloth</u></span></b></span></div><br />
<div style="text-align: justify;">Wiping with cloth is effective for removing only dust or foreign substances loosely adhering to components which can be reached by hand from outside. Use a clean dry lint-free cloth so that no waste material will adhere to the surface.</div><br />
<div style="text-align: center;"><u style="background-color: white; color: purple;"><b>Cleaning by blowing compressed air</b></u></div><br />
<div style="text-align: justify;">This method. is particularly effective for removing dry dust or foreign matters loosely adhering to the parts, which cannot be reached by hand from outside. The compressed air should be clean and dry, and at" pressure of 3-4 kg/cm2. Before blowing the compressed air against the coil, blow off water completely from the air pipes and hoses. The air must be filtered so that no adhesive particles can invade and damage the insulated portion or go under the insulation tape. Open both ends of the motor to provide a proper outlet for air and dust before starting to blow the compressed air. Even if the compressed air is blown against, this cleaning method is not effective unless dusts are taken outside of the motor in a proper way.</div><div style="text-align: justify;"><br />
</div><br />
<div style="text-align: center;"><span style="font-size: small;"><u style="color: purple;"><b>Cleaning by means of solvent</b></u></span></div><br />
<div style="text-align: justify;">Cleaning with solvent is effective for removing solid or stubborn dirt adhering to insulated surfaces, especially mixtures of grease, oil carbon and dust. After applying solvent, wipe off with clean cloth and then dry. Out recommended solvent is*the Rubber Benzine (JIS K2201-2 or Equivalent). </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><br />
<div style="background-color: red; text-align: center;"><b style="color: orange;"><span style="font-size: medium;">Caution</span></b></div></div><br />
<div style="text-align: justify;">When using a solvent, give full attention to the prevention of fire, explosion, and toxication. Besides the above cleaning methods, a steam cleaning method or a desalinating method can be available.<br />
<br />
<br />
<a href="http://hayatei.blogspot.com/2010/12/measurement-of-insulation-resistance.html">COIL AND INSULATION IN HIGH VOLTAGE MOTORS PART 2....... SOON</a></div>

COIL AND INSULATION IN HIGH VOLTAGE MOTORS

Inspection And Maintenance It is desirable that the insulation for the coil of motors is to be carefully kept clean and always dry. Therefo...

more information

TROUBLESHOOTING FOR H.V. MOTORS PART 3

<div style="text-align: center;"><h3 class="post-title entry-title"><span style="color: white; font-weight: normal;">TROUBLE SHOOTING FOR H.V. MOTORS PART 3 </span></h3><h3 class="post-title entry-title"><span style="font-size: large;"><a href="http://hayatei.blogspot.com/2010/12/trouble-shooting-for-hv-motors.html"><span style="font-family: Arial;">TROUBLE SHOOTING FOR H.V. MOTORS PART1</span></a></span><span style="font-size: large;">  </span></h3><h3 class="post-title entry-title"><span style="font-size: large;"> </span><span style="font-size: large;"><br />
</span></h3><h3 class="post-title entry-title"><span style="font-size: large;"><a href="http://hayatei.blogspot.com/2010/12/trouble-shooting-for-hv-motors-part-2.html">TROUBLE SHOOTING FOR H.V. MOTORS PART 2</a></span> </h3><span style="font-size: large;"><br />
</span></div><div style="text-align: center;"></div><div style="text-align: center;"><span style="font-size: large;"><u style="color: red;">Measurement Of Vibration</u></span></div><span style="font-size: large;"><br />
</span><br />
<div style="text-align: justify;"><span style="font-size: large;">Periodical measurement of vibration is vital for the maintenance of rotating machines. Although the amplitude of vibration is, of course, important, the causes of sizable changes in vibration must also be investigated to prevent accidents. Electric vibrometers are generally available and permit easy measurement of vibration amplitude.</span></div><span style="font-size: large;"><br />
</span><br />
<div style="text-align: center;"><span style="font-size: large;"><u style="color: red;">Allowable Values Of Vibration</u></span></div><span style="font-size: large;"><br />
</span><br />
<div style="text-align: justify;"><span style="font-size: large;">Measurements are to-be made of the vertical, horizontal and axial amplitudes of vibrations at the bearing and frame. Fig. 1-1 shows values of vibration currently employed by Mitsubishi Electric Corporation.</span></div><div style="text-align: justify;"></div><img alt="http://www12.0zz0.com/2010/12/17/11/679829160.png" src="http://www12.0zz0.com/2010/12/17/11/679829160.png" /><br />
<div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><br />
</div>

TROUBLESHOOTING FOR H.V. MOTORS PART 3

TROUBLE SHOOTING FOR H.V. MOTORS PART 3 TROUBLE SHOOTING FOR H.V. MOTORS PART1 TROUBLE SHOOTING FOR H.V. MOTORS PART 2 Measurement O...

more information

TROUBLESHOOTING FOR H.V. MOTORS PART 2

<a href="http://hayatei.blogspot.com/2010/12/trouble-shooting-for-hv-motors.html"><span style="font-family: Arial;">TROUBLE SHOOTING FOR H.V. MOTORS PART1</span></a><br />
<div class="MsoBodyTextIndent2" style="margin-right: 28.2pt; text-align: justify;"><br />
</div><span style="font-family: Arial;"><span style="color: white;">TROUBLE SHOOTING FOR H.V. MOTORS PART 2</span><br />
<u style="color: red;"><span style="font-size: large;"><br />
</span></u></span><br />
<div style="color: red; text-align: center;"><u><span style="font-family: Arial; font-size: large;">Limit Of Induction Motor's Temperature Rise</span><span style="font-size: large;"><br />
</span></u></div><span style="font-family: Arial;"><br />
<br />
The limit of temperature rise (temperatures at various parts minus ambient temperature) is prescribed by NEMA Standard MG1-20, 40 for each insulation material as shown in Table 1-2. The values given in table 1-2 show the temperature limits when the ambient reference temperature is 40ºC or lower. In case that the ambient temperature exceeds 40º C, the limit of temperature rise is to be reduced by the difference between the actual ambient temperature and 40º C.<br />
<br />
<br />
The observable temperature rise under rated-load conditions of each of the various parts of the induction motor, above the temperature of the cooling air, shall not exceed the values given in the following table. The temperature of the cooling air* is the temperature of the external air as it enters the ventilating openings of the machine, and the temperature rises given in the table are based on a maximum temperature or 40ºC for this external air. Temperatures <br />
shall be determined in accordance with the latest revision of IEEE Std 112, Test Procedure for Poly phase Induction Motors and Generators.<br />
<br />
</span><br />
<div style="color: purple; text-align: center;"><span style="font-family: Arial;"><span style="font-size: small;"><u>Table 1-2 NEMA Standard MG1-20,40 Temperature Rise</u></span></span></div><div class="MsoNormal" style="margin-left: 36pt; text-align: center;"><br />
</div><div></div><table border="1" cellpadding="0" cellspacing="0" class="MsoNormalTable" style="border-collapse: collapse; border: medium none; margin-left: auto; margin-right: auto; text-align: left;"><tbody>
<tr style="height: 26.7pt; page-break-inside: avoid;">   <td rowspan="2" style="-moz-background-clip: border; -moz-background-inline-policy: continuous; -moz-background-origin: padding; background: rgb(217, 217, 217) none repeat scroll 0% 0%; border-color: windowtext; border-style: double solid solid double; border-width: 4.5pt 1pt 2.25pt 4.5pt; height: 26.7pt; padding: 0cm 5.4pt; width: 36.9pt;" width="49"><div align="center" class="MsoNormal" style="text-align: center;"><b><span style="font-family: Arial; font-size: 11pt;">Item</span></b></div></td>   <td rowspan="2" style="-moz-background-clip: border; -moz-background-inline-policy: continuous; -moz-background-origin: padding; background: rgb(217, 217, 217) none repeat scroll 0% 0%; border-color: windowtext windowtext windowtext -moz-use-text-color; border-style: double solid solid none; border-width: 4.5pt 1pt 2.25pt medium; height: 26.7pt; padding: 0cm 5.4pt; width: 139.5pt;" width="186"><div align="center" class="MsoNormal" style="text-align: center;"><b><span style="font-family: Arial; font-size: 11pt;">Machine   Part</span></b></div></td>   <td rowspan="2" style="-moz-background-clip: border; -moz-background-inline-policy: continuous; -moz-background-origin: padding; background: rgb(217, 217, 217) none repeat scroll 0% 0%; border-color: windowtext windowtext windowtext -moz-use-text-color; border-style: double solid solid none; border-width: 4.5pt 1pt 2.25pt medium; height: 26.7pt; padding: 0cm 5.4pt; width: 103.5pt;" width="138"><div align="center" class="MsoNormal" style="text-align: center;"><b><span style="font-family: Arial; font-size: 11pt;">Method   of Temperature Determination A</span></b></div></td>   <td colspan="4" style="-moz-background-clip: border; -moz-background-inline-policy: continuous; -moz-background-origin: padding; background: rgb(217, 217, 217) none repeat scroll 0% 0%; border-color: windowtext windowtext windowtext -moz-use-text-color; border-style: double double solid none; border-width: 4.5pt 4.5pt 1pt medium; height: 26.7pt; padding: 0cm 5.4pt; width: 150.8pt;" width="201"><h3><b>Temperature Rise. Degrees C</b></h3><div align="center" class="MsoNormal" style="text-align: center;"><br />
</div><div align="center" class="MsoNormal" style="text-align: center;"><b><span style="font-family: Arial; font-size: 11pt;">Class   of Insulation System</span></b></div></td>  </tr>
<tr style="height: 6.45pt; page-break-inside: avoid;">   <td style="-moz-background-clip: border; -moz-background-inline-policy: continuous; -moz-background-origin: padding; background: rgb(217, 217, 217) none repeat scroll 0% 0%; border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 2.25pt medium; height: 6.45pt; padding: 0cm 5.4pt; width: 27.5pt;" width="37"><div align="center" class="MsoNormal" style="text-align: center;"><b><span style="font-family: Arial; font-size: 11pt;">A</span></b></div></td>   <td style="-moz-background-clip: border; -moz-background-inline-policy: continuous; -moz-background-origin: padding; background: rgb(217, 217, 217) none repeat scroll 0% 0%; border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 2.25pt medium; height: 6.45pt; padding: 0cm 5.4pt; width: 27.5pt;" width="37"><div align="center" class="MsoNormal" style="text-align: center;"><b><span style="font-family: Arial; font-size: 11pt;">B</span></b></div></td>   <td style="-moz-background-clip: border; -moz-background-inline-policy: continuous; -moz-background-origin: padding; background: rgb(217, 217, 217) none repeat scroll 0% 0%; border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 2.25pt medium; height: 6.45pt; padding: 0cm 5.4pt; width: 42.35pt;" width="56"><div align="center" class="MsoNormal" style="text-align: center;"><b><span style="font-family: Arial; font-size: 11pt;">F</span></b></div></td>   <td style="-moz-background-clip: border; -moz-background-inline-policy: continuous; -moz-background-origin: padding; background: rgb(217, 217, 217) none repeat scroll 0% 0%; border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; border-style: none double solid none; border-width: medium 4.5pt 2.25pt medium; height: 6.45pt; padding: 0cm 5.4pt; width: 53.45pt;" width="71"><div align="center" class="MsoNormal" style="text-align: center;"><b><span style="font-family: Arial; font-size: 11pt;">H</span></b></div></td>  </tr>
<tr style="height: 70.55pt;">   <td style="border-color: -moz-use-text-color windowtext windowtext; border-style: none solid solid double; border-width: medium 1pt 1pt 4.5pt; height: 70.55pt; padding: 0cm 5.4pt; width: 36.9pt;" width="49"><div align="center" class="MsoNormal" style="text-align: center;"><b><span style="font-family: Arial; font-size: 11pt;">1</span></b></div></td>   <td style="border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; height: 70.55pt; padding: 0cm 5.4pt; width: 139.5pt;" width="186"><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">Insulated   windings</span></div><div class="MsoNormal" style="margin: 0cm -0.9pt 0.0001pt 24pt; text-indent: -18pt;"><b><span style="font-family: Arial; font-size: 11pt;">a.<span style="font-family: "Times New Roman"; font-size-adjust: none; font-size: 7pt; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal;">      </span></span></b><span dir="LTR"><span style="font-family: Arial; font-size: 11pt;">All horsepower ratings</span></span></div><div class="MsoNormal" style="margin: 0cm 3.6pt 0.0001pt 24pt; text-indent: -18pt;"><b><span style="font-family: Arial; font-size: 11pt;">b.<span style="font-family: "Times New Roman"; font-size-adjust: none; font-size: 7pt; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal;">      </span></span></b><span dir="LTR"><span style="font-family: Arial; font-size: 11pt;">1500 horsepower and less.</span></span></div><div class="MsoNormal" style="margin: 0cm -0.9pt 0.0001pt 24pt; text-indent: -18pt;"><b><span style="font-family: Arial; font-size: 11pt;">c.<span style="font-family: "Times New Roman"; font-size-adjust: none; font-size: 7pt; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal;">      </span></span></b><span dir="LTR"><span style="font-family: Arial; font-size: 11pt;">Over 1500 horsepower</span></span></div><div class="MsoNormal" style="margin-left: 1.45pt;"><span style="font-family: Arial; font-size: 11pt;"> <b>1.</b>    7000 volts and less. </span></div><div class="MsoNormal" style="margin: 0cm 24pt 0.0001pt 0.95pt;"><span style="font-family: Arial; font-size: 11pt;">  <b>2.</b> Over 7000 volts.</span></div></td>   <td style="border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; height: 70.55pt; padding: 0cm 5.4pt; width: 103.5pt;" width="138"><div class="MsoNormal"><br />
</div><div class="MsoNormal"><span style="font-family: Arial; font-size: 11pt;">Resistance</span></div><div class="MsoNormal"><span style="font-family: Arial; font-size: 11pt;">Embedded detector</span></div><div class="MsoNormal"><br />
</div><div class="MsoNormal"><span style="font-family: Arial; font-size: 11pt;">Embedded detector</span></div><div class="MsoNormal"><span style="font-family: Arial; font-size: 11pt;">Embedded detector</span></div></td>   <td style="border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; height: 70.55pt; padding: 0cm 5.4pt; width: 27.5pt;" width="37"><div align="center" class="MsoNormal" style="text-align: center;"><br />
</div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">60</span></div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">70</span></div><div align="center" class="MsoNormal" style="text-align: center;"><br />
</div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">65</span></div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">60</span></div></td>   <td style="border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; height: 70.55pt; padding: 0cm 5.4pt; width: 27.5pt;" width="37"><div align="center" class="MsoNormal" style="text-align: center;"><br />
</div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">80</span></div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">90</span></div><div align="center" class="MsoNormal" style="text-align: center;"><br />
</div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">85</span></div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">80</span></div></td>   <td style="border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; height: 70.55pt; padding: 0cm 5.4pt; width: 42.35pt;" width="56"><div align="center" class="MsoNormal" style="text-align: center;"><br />
</div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">105*1</span></div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">115*2</span></div><div align="center" class="MsoNormal" style="text-align: center;"><br />
</div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">110*3</span></div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">105</span></div></td>   <td style="border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; border-style: none double solid none; border-width: medium 4.5pt 1pt medium; height: 70.55pt; padding: 0cm 5.4pt; width: 53.45pt;" width="71"><div align="center" class="MsoNormal" style="text-align: center;"><br />
</div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">125</span></div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">140</span></div><div align="center" class="MsoNormal" style="text-align: center;"><br />
</div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">135</span></div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">125</span></div></td>  </tr>
<tr style="height: 31.2pt; page-break-inside: avoid;">   <td style="border-color: -moz-use-text-color windowtext windowtext; border-style: none solid double double; border-width: medium 1pt 4.5pt 4.5pt; height: 31.2pt; padding: 0cm 5.4pt; width: 36.9pt;" width="49"><div align="center" class="MsoNormal" style="text-align: center;"><b><span style="font-family: Arial; font-size: 11pt;">2</span></b></div></td>   <td colspan="6" style="border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; border-style: none double double none; border-width: medium 4.5pt 4.5pt medium; height: 31.2pt; padding: 0cm 5.4pt; width: 393.8pt;" width="525"><div class="MsoNormal"><span style="font-family: Arial; font-size: 11pt;">Cores, squirrel – cage windings and mechanical   parts, such as collector rings and brushes, may attain such temperatures as   will not injure the machine in any respect. </span></div></td>  </tr>
</tbody></table><div style="text-align: center;"></div><div class="MsoNormal" style="margin: 0cm 28.2pt 0.0001pt 72pt; text-align: center; text-indent: -36pt;"></div><br />
<div></div><br />
<br />
<div></div><div><div class="MsoNormal" style="margin: 0cm 28.2pt 0.0001pt 72pt; text-align: justify; text-indent: -36pt;"><br />
For totally-enclosed water-air-cooled machines, the temperature of the cooling air is the temperature of the air leaving the coolers. See Note 1<br />
<br />
<br />
<br />
Embedded detectors are located within the slot of the machine and can be either resistance elements or thermocouples. For motors equipped with embedded detectors, this method shall be used to demonstrate conformity with the standards.<br />
<br />
<br />
<br />
<br />
<br />
<br />
NOTE :- Totally-enclosed water-air-cooled machines are normally designed for the maximum cooling water temperature encountered at the location where each machine is to be installed. With a cooling water temperature not exceeding that for which machine is designed.<br />
<br />
<br />
a.      On machines designed for cooling water temperature up to 30ºC-the temperature of the air leaving the coolers shall not exceed 40 ºC.<br />
<br />
<br />
b.      On machines designed for higher cooling water temperature-the temperature of the air leaving the coolers may exceed 40ºC provided the temperature rises of the machine parts are then limited to values less than those given in the table by the number of degrees that the temperature of the air leaving the coolers exceed 40ºC.<br />
<br />
<br />
NOTE :- For motors which operate under prevailing barometric pressure and which are designed not to exceed the specified temperature rise at altitudes from 3300 feet (1100 meters) to 13000 feet (14000 meters). The temperature rises as checked by tests at low altitudes, shall be less than those used in the foregoing table by 1 percent of the specified temperature rise for each 330 feet (100 meters) of altitude in excess of 3300 feet (1000 meters).<br />
<br />
<br />
NOTE :- Temperature rises in the foregoing table are based upon a reference ambient temperature of 40ºC. However it is recognized that induction motors may be required. to operate in an ambient temperature higher than 40ºC. For successful operation of the motors in ambient temperatures higher than 40ºC. It is recommended that the temperature rises of the motors given in the foregoing table be reduced, as indicated below, for the ranges of ambient temperature given. (Exception-for totally-enclosed water-air-cooled machines. see NOTE I.)</div><div class="MsoNormal" style="margin: 0cm 28.2pt 0.0001pt 72pt; text-align: justify; text-indent: -36pt;"></div></div><div style="text-align: center;"><div align="center"><table border="1" cellpadding="0" cellspacing="0" class="MsoNormalTable" style="border-collapse: collapse; border: medium none; margin-left: 5.4pt;"><tbody>
<tr>   <td style="-moz-background-clip: border; -moz-background-inline-policy: continuous; -moz-background-origin: padding; background: rgb(217, 217, 217) none repeat scroll 0% 0%; border-color: windowtext; border-style: double solid solid double; border-width: 4.5pt 1pt 1pt 4.5pt; padding: 0cm 5.4pt; width: 199.5pt;" width="266"><div align="center" class="MsoNormal" style="text-align: center;"><b><span style="font-family: Arial; font-size: 11pt;">Ambient   Temperature Degrees C</span></b></div></td>   <td style="-moz-background-clip: border; -moz-background-inline-policy: continuous; -moz-background-origin: padding; background: rgb(217, 217, 217) none repeat scroll 0% 0%; border-color: windowtext windowtext windowtext -moz-use-text-color; border-style: double double solid none; border-width: 4.5pt 4.5pt 1pt medium; padding: 0cm 5.4pt; width: 232.5pt;" width="310"><div class="MsoNormal"><b><span style="font-family: Arial; font-size: 11pt;">Values by which Temperature Rises in the   Foregoing table Should be Reduced in Degrees ºC</span></b></div></td>  </tr>
<tr style="height: 30.45pt;">   <td style="border-color: -moz-use-text-color windowtext windowtext; border-style: none solid double double; border-width: medium 1pt 4.5pt 4.5pt; height: 30.45pt; padding: 0cm 5.4pt; width: 199.5pt;" width="266"><div class="MsoNormal"><span style="font-family: Arial; font-size: 11pt;">Above 40 up to and including   30</span></div><div class="MsoNormal"><span style="font-family: Arial; font-size: 11pt;">Above 50 up to and including   60</span></div></td>   <td style="border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color; border-style: none double double none; border-width: medium 4.5pt 4.5pt medium; height: 30.45pt; padding: 0cm 5.4pt; width: 232.5pt;" width="310"><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">10</span></div><div align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: Arial; font-size: 11pt;">20</span></div></td>  </tr>
</tbody></table></div></div><div style="text-align: center;">For 190 KW, 200 KW & 230 KW L.V.<br />
motors For 570 KW, 6.9 KV Horizontal Motors.<br />
For 2620 KW & 1420 KW, 6.9 KV Vertical Motors<br />
<br />
<div style="text-align: justify;"><br />
</div></div><div style="text-align: center;"><span style="font-family: Arial;"><br />
Caution:-<br />
<br />
</span><br />
<div style="text-align: justify;"><span style="font-family: Arial;">Since the motor temperature would rises until the heat produced by copper loss, iron loss and mechanical loss is balanced with the heat dissipated by ventilation, the ventilation system requires special attention. Particularly, it must be noted that an obstacle close to the ventilating part or narrowing of the part by accumulated dust when the motor is used in a dusty place will cause the abnormal temperature rise of the motor. Each motor, when delivered, is accompanied by a test report showing the temperature rises of the coil, core and other parts at the time of the shop test. it is necessary to measure the actual temperature of the motor from time to time to ascertain that the measured values are not much different from those obtained in the shop test.</span></div><span style="font-family: Arial;"><br />
</span><br />
<div class="MsoNormal" style="margin: 0cm 72pt 0.0001pt; text-align: justify; text-indent: -18pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 72pt 0.0001pt; text-align: justify; text-indent: -18pt;"></div>TROUBLE SHOOTING FOR H.V. MOTORS PART 3 ....SOON</div>

TROUBLESHOOTING FOR H.V. MOTORS PART 2

TROUBLE SHOOTING FOR H.V. MOTORS PART1 TROUBLE SHOOTING FOR H.V. MOTORS PART 2 Limit Of Induction Motor's Temperature Rise The l...

more information