Motor Performance curves

[Charz]

I have been asked to evaluate the below curves from the motor manufacturer.

1. Time current Curves - what is the purpose of these curves, if vendor has already mentioned the FLC(Full Load current), LRC(Locked rotor current) in the datasheet.
2. Speed Torque Curves / Speed Current Curves - Combined in one curve- Apart from if the motor could successfully accelerate the load at 0.8 and 1.0 P.U voltages, What is the need of these curves?
3. Thermal Limit Curves - Hot/Cold withstand times have been already mentioned in the datasheet. This curve can be used for relay setting. Any other information from this curve?
4. Speed Vs Power factor curve - What is the purpose of this curve?

Apart from the above, What checks/verifications do I need to perform with these curves?

 

[paulengr]

I have been asked to evaluate the below curves from the motor manufacturer.

1. Time current Curves - what is the purpose of these curves, if vendor has already mentioned the FLC(Full Load current), LRC(Locked rotor current) in the datasheet.
2. Speed Torque Curves / Speed Current Curves - Combined in one curve- Apart from if the motor could successfully accelerate the load at 0.8 and 1.0 P.U voltages, What is the need of these curves?
3. Thermal Limit Curves - Hot/Cold withstand times have been already mentioned in the datasheet. This curve can be used for relay setting. Any other information from this curve?
4. Speed Vs Power factor curve - What is the purpose of this curve?

Apart from the above, What checks/verifications do I need to perform with these curves?

What are you evaluating it against? You can’t evaluate anything without criteria for it.

 

[topgone]

I have been asked to evaluate the below curves from the motor manufacturer.

1. Time current Curves - what is the purpose of these curves, if vendor has already mentioned the FLC(Full Load current), LRC(Locked rotor current) in the datasheet.
2. Speed Torque Curves / Speed Current Curves - Combined in one curve- Apart from if the motor could successfully accelerate the load at 0.8 and 1.0 P.U voltages, What is the need of these curves?
3. Thermal Limit Curves - Hot/Cold withstand times have been already mentioned in the datasheet. This curve can be used for relay setting. Any other information from this curve?
4. Speed Vs Power factor curve - What is the purpose of this curve?

Apart from the above, What checks/verifications do I need to perform with these curves?

Basically, those are performance curves. It tells you how the motor will behave and what are the capabilities their product can provide you aside from the basic ratings stated in the nameplate. For me, these are important especially if you are trying to fit a certain motor to a new load requirement or you are tweaking a process parameter to fit a new setup (say you wanted to operate at a different rotor speed and you don't know if your motor can give you the desired performance, the speed-torque curve tells you whether the operating point you wanted is beyond or within the motor's operating range.):

• Time-current curves --> shows you of the plot of the motor current at different times when motor is energized.
• Speed-Torque curves --> tells you the rotor speed at different motor loading.
• Thermal limit curves --> tells you how far you can stretch your settings in order to prevent motor from burning out.
• Speed vs Power factor curve --> power factor is synonymous 'with motor efficiency. You want to know if the motor efficiency is not bad at certain operating speeds.