What voltage

[ptonsparky]

Should I use the voltage rating of the motor (230V) to select the drive or the POCO voltage of 208Y? The drive is the variable in this equation.

 

[charlie]

In my opinion, you should not use a 230 volt motor on a 208 volt system unless the motor is rated for both voltages.

 

[ptonsparky]

Agreed but that wasn't in the list of multiple choices.

The motor is an existing 20 hp submersible that will not be changed until it dies. The POCO changed the service from an open delta to 208Y a couple years ago. Now the customers want a VFD with all its bennies.

 

[physis]

Should I use the voltage rating of the motor (230V) to select the drive or the POCO voltage of 208Y?

If you're gonna use a VFD get one that drives the motor, they don't drive the power company. They're driven by the power company. 208 in and 230 out, right? Or is there something I'm missing?

 

[winnie]

It won't make a difference. You are going to use a '200V class' drive. You will need to make sure that it is rated for operation down to the lowest expected input voltage (eg. 208V - 10%).

You will need to size the drive based upon current handling capacity, both input and output.

Most drives will only be able to produce an output voltage equal to the input voltage. If you reduce the maximum speed of the motor then the drive will be able to support proper magnetization. Some drives have a boost converter on the input stage; these can produce higher output voltage than input. Examples are drives capable of line regeneration.

-Jon

 

[Besoeker]

Most drives will only be able to produce an output voltage equal to the input voltage. If you reduce the maximum speed of the motor then the drive will be able to support proper magnetization. Some drives have a boost converter on the input stage; these can produce higher output voltage than input. Examples are drives capable of line regeneration.

-Jon

I agree with what you have said. If the Pton wants to get full rating from his motor, a drive with a boost converter would be one way to go. Maybe a step up autotransformer on the input would be cheaper?

 

[ptonsparky]

Never thought about a buck/boost transformer on the incoming. Good idea for future, Could I elimnate a line side reactor by using buck/boost(s)?

Reducing the max speed may be just the ticket because the pump is oversized and cycles frequently even during times of max usage.

Thank you

 

[winnie]

Never thought about a buck/boost transformer on the incoming. Good idea for future, Could I elimnate a line side reactor by using buck/boost(s)?

I don't know if you can use a buck-boost in this fashion. When I last installed a line regen drive, the documentation specified a certain required impedance on the supply side, which could be provided by a line reactor _or_ transformer.

-Jon

 

[Besoeker]

I don't know if you can use a buck-boost in this fashion. When I last installed a line regen drive, the documentation specified a certain required impedance on the supply side, which could be provided by a line reactor _or_ transformer.

-Jon

I was suggesting the autotransformer as an alternative to the regen drive.

 

[LarryFine]

Should I use the voltage rating of the motor (230V) to select the drive or the POCO voltage of 208Y?

I would think you should specify both, the supply and the load, since both are variables when selecting VFD's.