The Indian Electric Co

FAQ

Q 01.
Can a 1500 RPM motor be run at 3000 RPM by frequency inverter application?
No. It will have mechanical problems like bearing failure.
Q 02.
Why one has to buy higher frame size motor if it is to be used with frequency inverter applications?
If the motor is run at lower speed, cooling will be insufficient. With a higher frame motor more surface area for cooling will be available.
Q 03.
What is the significance of using only a particular speed motor with a particular application?
What are the consequences if 3000 RPM motor is used in place of 1500 RPM motor or vice versa?
Driven equipment is designed to run at particular speed only. If it is run at higher speed, mechanical damage and accident may occur. If it is run at lower speed, output will be less than rated.
Q 04.
What is the full load current of the motor?
Please refer the performance chart for the motor in the relevant section on this website.
Q 05.
What is the starting current of the motor?
Please refer the performance chart for the motor in the relevant section on this website.
Q 06.
What is the size of starter and overload relay range required for a particular motor?
his has to be obtained from the starter supplier.
Q 07.
What is the full load torque of the motor?
Please refer the performance chart for the motor in the relevant section on this website.
Q 08.
What is the starting torque of the motor?
Please refer the performance chart for the motor in the relevant section on this website.
Q 09.
What is the method of starting for a particular motor.- DOL, Star-Delta, Rotor Resistance
Normally for small motors upto 10 HP - DOL, for 10 HP and above ratings star-delta and for slipring motors - Rotor
resistance.
Q 10.
How many times a motor can be started in an hour without any harmful effect on the winding?
2 Hot, 3 Cold and 4 Equally spaced starts for S1 duty motors.
Q 11.
What is the safe limit of the body temperature of the motor?
As per insulation class of the winding. Please refer relevant chart for insulation in the related section on this web site.
Q 12.
What is the significance of Ambient Temperature on performance of the motor?
Increase in ambient temperature will affect the output/KW of the motor.
Q 13.
What is the difference between Class ‘B’ and Class ‘F’ insulations ? Which is better?
Temperature withstanding capacity of the motor winding differs with the class of insulation material used. Class ‘B’ insulation temperature limit is 130 0C. Class ‘F’ insulation temperature limit is 155 0C. Naturally Class ‘F’ is better than Class ‘B’.
Q 14.
Can the motor winding withstand heavy fluctuations in the supply voltage ? What is the effect of surges on the winding?
Yes, to a certain limit. Apart from insulation failure, mechanical stresses also take place due to voltage surges in motor
winding.
Q 15.
At what minimum supply voltage the motor can be safely started without harmful effect on the winding?
90 % of rated voltage.
Q 16.
What is the minimum time required by the motor to attain full speed at the rated load?
As per IS 325.
Q 17.
What are the percentage efficiencies of the motor at full, half and quarter loads?
Please refer the performance chart for the relevant motor in the related section on this web site.
Q 18.
What is the motor power factor at full, half and quarter load?
Please refer the performance chart for the relevant motor in the related section on this web site.
Q 19.
What is the value of per phase winding resistance of the motor?
Please refer the performance chart for the relevant motor in the related section on this web site.
Q 20.
What is the rated speed of the motor?
Please refer the performance chart for the relevant motor in the related section on this web site.
Q 21.
The type of lubricant and quantity for first filling.
Please refer the Bearing chart in the related section on this web site.
Q 22.
Frequency of regreasing and quantity of grease required?
Please refer the Bearing chart in the related section on this web site.
Q 23.
Type and Size of bearing
Please refer the Bearing chart in the related section on this web site.
Q 24.
What are the hot and cold thermal withstand times?
Please refer the performance chart for the relevant motor in the related section on this web site.
Q 25.
What is value of GD2 of the motor?
Please refer the performance chart for the relevant motor in the related section on this web site.
Q 26.
In what way low supply voltage affects performance of the motor? What are the consequences?
The motor will draw high current. If it runs continuously at low voltage, winding may get burnt.
Q 27.
At what percentage of the rated voltage the motor can be run safely on rated load?
90% of rated supply voltage.
Q 28.
What are the values in percentage of pull out and pull up Torques in respect of rated or full load Torque?
Please refer the performance chart for the relevant motor in the related section on this web site.
Q 29.
Is a standard 415V motor suitable for 380V operations?
No, 380 V rating motors are to be separately procured at extra cost.
Q 30.
Can the 50Hz frame motor be run at 60Hz frequency without any alteration?
No, Such a motor shall have to be manufactured specially and will be available at extra cost.
Q 31.
Does the motor have double shaft Extention?
Normally not. But a double shaft extension can be supplied on request at extra Cost.
Q 32.
Can the motors upto 90 frame and for 6 & 8 poles in 100 frame be supplied with 6 studs terminal board?
Yes, at extra Cost.
Q 33.
Are there differences between old and new frame sizes and also between KEC make and other makes?
Major dimensions do not differ. All renowned manufacturers adopt same international standards and hence frame sizes do not differ.
Q 34.
Can the motor be supplied with thermistors and space heaters? What are the functions of thermistors and space heaters?
Yes, at extra cost. Thermistors monitor winding temperature and space heaters are used to keep winding warm during idle stage.
Q 35.
Can a stainless steel nameplate be provided for the motor?
Yes, at extra cost.
Q 36.
Can Lubrication details nameplate be provided for the motor?
Yes, at extra cost.
Q 37.
What does the frame size of the motor indicate? What do the prefix letters KH, PM, BPM LD/SC etc indicate?
It mainly indicates the shaft centre to base plate height in millimeters. Prefix letters are mainly abbreviations of manufacturers code like KH-Kirloskar Hubli, PM - Primo etc.