New MV drive on old motors

[QES]

I am working on a project installing a Medium Voltage drive an old induction motor (4160V, 2000HP). I am interested in hearing peoples thoughts on the different drive technologies and manufactures out there. For instance, ABB offers a standard PWM inverter at 4160V, 2000HP with an sine wave filter on the inverter output. Toshiba offers a multi-step PWM inverter at 4160V, 2000HP.

Which of these drives or others are easier on the motors as far as dv/dt at the motor terminals? Are there other manufacturers or technologies that are better? Any other thoughts on the subject?

Thanks for the responses.

 

[jcormack]

Type of load?

Type of load?

What is your load? Fan, Pump, Crusher, Belt?
Variable torque? Constant Torque? Any regeneration issues?

The basic technologies you will find are voltage source PWM (Toshiba, ABB, TEMAC) or current source (Rockwell). Most voltage source units will have seriesed power sections/devices to get the voltage & may need parallel power sections/devices for current. My guess at 2000 hp it would be 18 or 24 pulse requiring a multi-secondary transformer (usually built-in). A current source inverter usually uses SCR technology & uses less power devices for the same hp. the Rockwell Powerflex 7000, for example is SCR based and has an active front end to handle regeneration, if needed. Most of the voltage source PWM units at 2000 hp do not yet have active front ends (ABB is working on one) so you have to use large Resistor banks off the DC Buss to dump regen energy. If Regen is not an issue anyones MVVFD will work if sized properly.

 

[weressl]

I am working on a project installing a Medium Voltage drive an old induction motor (4160V, 2000HP). I am interested in hearing peoples thoughts on the different drive technologies and manufactures out there. For instance, ABB offers a standard PWM inverter at 4160V, 2000HP with an sine wave filter on the inverter output. Toshiba offers a multi-step PWM inverter at 4160V, 2000HP.

Which of these drives or others are easier on the motors as far as dv/dt at the motor terminals? Are there other manufacturers or technologies that are better? Any other thoughts on the subject?

Thanks for the responses.

I used both. on MV the winding insulation issue does not seem to be a problem, but I would write it into a performance specification for the manufacturer so that thye come and fine-tune the application to minimize 'ringing'.

One thing, as a minimum, you must do to prepare the motor for this service; isolate the driven end bearing. I would also contact the motor AND the driven equipment manufacturer with the intended operating parameters.

You also want to check your lubrication system, because if it is shaft driven, you may not get sufficient flow of lubricant.

The cooling provision should also be checked, both for the winding and the lubrication.