220V motor on 208V?
- Thread starter olc
- Start date
- Status
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
Generally if it is under 10HP, the differences are immaterial. Smaller motors are manufactured under a compromise based on using a 220V design base +-10%, which makes them suitable for 198 - 244V, and it is generally accepted that 208V is used in "smaller" facilities where the distance from the service drop to the motor will not make it so that the VD is severe enough to go lower than that.
If it is 10HP and over, it is considered better to use a motor designed for 200V operation, but people feed 230V motors with 208V all the time and just accept the risk of a potentially shortened life span of the motor that will be the result.
kingpb
Senior Member
- Location
- SE USA as far as you can go
- Occupation
- Engineer, Registered
You will not get the same Hp out of the motors at reduced voltage. You need to look at the Hp and torque requirements. The motor will also not last as long, maybe as low as 50%.
kwired
Electron manager
- Location
- NE Nebraska
Why not? You can get more then rated HP out of any motor, the cost is increased current and increased heating most likely resulting in shorter life. Generally motors will try to deliver the load being demanded from them and if voltage is too high or too low it compensates with a change in current. It can get much more complex then that, but that is generally a good base of what will happen.
kingpb
Senior Member
- Location
- SE USA as far as you can go
- Occupation
- Engineer, Registered
I agree, I should have clarified that to maintain heat within limits and retain motor life expectancy, you would need to reduce the Hp.
kwired
Electron manager
- Location
- NE Nebraska
:thumbsup:
Maybe he won't need it if he is using a VFD.
You can't get 230V out with 208V in.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
The day I figure out how to make a drive create something that isn't there, I'll be fabulously wealthy enough to kill myself with excess pleasure. So if I ever stop posting here, you'll know what happened...:thumbsup:
I don't know whether to wish you well or badly in your endeavours............
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
You could if the drive included a boost converter for the DC. But nobody would be willing to pay for that when they could just use a boost transformer on the input instead.
I just knew some pedant would come up with that.............
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
I just knew some pedant would come up with that.............
You still cannot get something for nothing though, AFAIK.
Although we do seem to have a member or two who cannot accept that.
Aleman
Senior Member
- Location
- Southern Ca, USA
I don't think you will see any problems with it. If you think about it you will be about 5% low on the voltage which
in practice isn't a big deal. Transformers are not cheap, unless you want to waste some money.
in practice isn't a big deal. Transformers are not cheap, unless you want to waste some money.
Plus whatever tolerance limits apply to the 208V supply.
YW!I stand corrected.
Some of us here routinely deal with variable speed drives so there is quite a pool of knowledge to tap into.
- Status