Motors:

[WSteinhardt73]

I am working on a swimming pool on an Army base. They have changed the pump motor on it several times already. The service supplying power is 120/240V delta. The motor they keep ordering is a Century 10/7.5 hp, 220/440 & 190/380 3 phase motor. Will this motor work with this service or is it the wrong one? I’m thinking they need one that is rated 208/230, is this correct?

 

[jim dungar]

I believe they are ordering the correct motor. A 4-wire delta service will have 240V L-L like the motor is looking for.
The motor does not care about L-N voltage , although the pump control board probably does.
I do think any motor with a nameplate showing 220/440V will not last as long as one listing 230/460V.

 

[ActionDave]

It's not unusual for a pump manufacturer to put too much pump on too small a motor figuring odds are it won't run at Max flow. Has anyone checked the running amps?

 

[Jraef]

The fact that the motor has a 190/380V label indicates that it was really designed as an IEC motor, which they are re-labeling for use in North America by "allowing" the +-% voltage range to be +15% to get to 220V. But that would be a stretch to begin with so it is 220V + 0%. But we have 240V which is +26% of what that motor is actually designed for and is likely leading to saturation and over heating, then premature failure. I would buck that down to something closer to (if not a little below) 220V since that's what it actually says on the label.

Or replace it with a 230V rated motor designed for use here. The problem may be however that if it is an IEC motor, the shaft will be metric and the mounting will be different than what we use. May be a trickier project to replace the motor, making the buck transformer a simpler fix for you, the electrician.

 

[winnie]

But wouldn't that IEC motor be designed for 190/380V at 50Hz, and is now being used at 240V and 60Hz?

 

[Jraef]

If the motor were designed here, I don't think it would have a label for 380V.
But you may have a point. If designed there for 380V 50Hz, and ADAPTED for use on 220 or 440V, the design V/Hz ratio would have been 7.6:1 for 380V or 3.8:1 at 190V, If 240V 60Hz were applied, that is a 4:1 ratio, which is within 5% of the design ratio, albeit 5% high. But if it WERE designed for a 3.8 V/Hz ratio, why label it for 220V? That would be closer to 230V at 60Hz, so more normal to what we expect.

It's likely this motor is some cheap junk from China where someone didn't really know what we have available over hear so they are reading some data sheet from before Mao Zedong that said we had 220 and 440, which would have been true in the 1940s...