Created Date: December 10,2019

Created by: ethan_adam

i'm installing a GS4 drive. With no load, a 13.5amp motor is pulling up to 30amps at low hz. when i get above 10hz it settles down to about 10 amps.

i work with extruders and have one other small machine that has an identical symptom. it's not a huge problem with the machine already in service because the machine is never ran at that low of an rpm, i just have my rpm meter blink green (indicating to the operator to raise the rpms) until the rpms until it reaches the point where the amps fall to normal. otherwise the drive faults. i'd like to be able to make this problem not happen at all.

it's a 3 phase 480v motor.

i'm also curious about the "# of poles " parameter. when setting up a 3 phase motor, is that considered 4 poles... ground being one of them?

Created Date: December 10,2019

Created by: MikeN

If you use constant torque mode it raises the amperage a good bit to maintain full torque at low RPM.

Unfortunately this doesnt mesh with the default setting in the overcurrent threshold. You will need to raise the default setting significantly or turn it off altogether to keep the drive from faulting out.

As for the number of poles, I dont remember exactly what it is but the setting has to due with motor construction itself and the RPM the motor is rated for. The calculation should be in the manual for that parameter description, but default setting is normally correct for a standard 1800RPM synchronous speed motor

Created Date: December 10,2019

Created by: akahammer

Motor Poles-Our frequency being 60 hz and the number of poles determine the motor base speed. so two pole motor is 3600 rpm base speed, 4 pole 1800 rpm base speed etc. Look at motor nameplate it will say something less than 3600, like 3450 this would be a two pole motor, or something less than 1800 like 1740 that would be a 4 pole motor, the difference between base speed and nameplate speed is the slip of the motor, as the motors load increases slip will increase as slip increases the motor has the ability to produce more torque. If slip was zero(motor poles stator aligned with rotor) the motor would produce no torque, slip is necessary to produce torque in motor. Different motor designs produce different amount of slip and is directly related to the torque they can produce. Most motor design in service are Design Type "B ", there are other design types "C " and " D " etc..they have more slip than design "B " and can produce more torque. They will also require more current to produce more torque. Hope this helps with your motor poles question.

Also I would run the auto tune with no load on motor, the drive does some measurements and calculations to determine how to best drive motor after auto tune the drive sets several parameters for you. Also look at Parameter P2.00 you can select a preset operation curve default is 0, you will probably want 1 high start torque. (basically boosts voltage at lower speeds)Nothing is for free higher torque at lower speeds will had more heat so pay attention after any changes.