265v motor on 240v vfd?

Pretty much as the title says, looking at a blower rated 265v delta/ 460 y. Are VFD output voltages proportional to input? Seeing as my single phase is around 250v I'm thinking I should have no problem running it wired delta off a 240v class drive with 250v in?

Looks like a motor that actually wants 277/480v.

So you have a blower or fan load which has a cubic power curve. Usually the motors are oversized by 25% so the motor is nominally at its most efficient point, 75% nameplate hp, and this also provides margin for overload or low voltage.

You will likely be just fine on a 240v vfd programmed for 277v 60hz. You will only get 240vac out of it, with 250vac going in.

Check the motor amps. If high, reduce the frequency slightlyb wont take much.

If you absolutely need full speed add a buck boost ahead of the vfd. Most 240v vfds will run fine up to 400vdc or 275 to 280vac input.

I'm kinda thinking it is indeed a 265v motor. Looks to be more a European design and geussing it's meant to be okay but not ideal for both US and overseas voltages. Also I'm not aware of anyone running three phase motors on 277 here. If you have 277 you have 480 and just use that. Anyways for my application I'll be running it intermittently and not under full load so sounds like I should be fine. Thanks

are you sure its a 60hz motor?


if its a 50hz motor it will need more volts, in such a case program the vfd for 277v/50hz and then run the rpm up until your amps reach nameplate or a bit higher within reasonable limits. should be no problem.

johansen said:

are you sure its a 60hz motor?


if its a 50hz motor it will need more volts, in such a case program the vfd for 277v/50hz and then run the rpm up until your amps reach nameplate or a bit higher within reasonable limits. should be no problem.

Click to expand...

I'm going off the manufacturer data sheet, which states 60 hz 3450 rpm.
So I'd trust their specs on it.

Your voltage will be a little lower at the motor than the drive terminals because of losses in the cable. Let's assume that the motor terminal voltage will be 235 volts. A 240 volt drive is normally matched to a 230 volt motor. You also should not set it for your highest possible voltage as your incoming voltage levels can change over time - I would leave some head room.

Up to base speed (60 hz, 3450 rpm) the motor will typically run in constant volts per hertz. With that you have constant torque up to base speed and constant horsepower over base speed.

With your setup, you would get full torque up to 235 volts (3060 rpm). Above 3060 rpm, the voltage would stay the same but the hertz would continue to increase and the torque starts dropping off all the way to 3450 rpm.

At the end of the day, at 3450 rpm you would have approximately 90% of rated torque and horsepower at rated speed (3450 rpm). It will be proportionally higher if you have higher output voltage.

You should tell the drive that the motor is a 235 volt, 3059 rpm, 53.2 hertz motor but set the max rpm to 60 hz. That will give you the results I mentioned above.

A 265V motor is intended for a 277V supply, a 265V PTAC unit used in a hotel room is a common use for a 265V motor.