Is 208v acceptable in a 2hp 115/230v motor

F

Flygonkick

Member
Location
Michigan
Occupation
Electrician
I have a 2HP 115/230v pump being installed where I work and I wanted to get opinions on if it would be okay to run 208 to the motor or if I should get a step up transformer to 230 or 240
 
Since you have 208 available, you probably have 120V as well. If so, I’d run the motor at the low voltage connection.

Operating at 208 will likely operate fine, perhaps with shortened life, but why chance it if you have a proper voltage available?
 
retirede said:
Since you have 208 available, you probably have 120V as well. If so, I’d run the motor at the low voltage connection.

Operating at 208 will likely operate fine, perhaps with shortened life, but why chance it if you have a proper voltage available?
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The main reason I'm looking at using the 208 or even a step up transformer is because the 208 panel is within 50 feet of the pump installation and the 120 panel is closer to 100 yards away. Gotta love old school buildings.
 
Flygonkick said:
The main reason I'm looking at using the 208 or even a step up transformer is because the 208 panel is within 50 feet of the pump installation and the 120 panel is closer to 100 yards away. Gotta love old school buildings.
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So no neutral in the 208 panel.

In that case, I agree with others - run it on 208V. I would check the running amps after startup to confirm they are not greater than the service factor amps.
 
It completely depends on the load placed on the motor.

If the motor is lightly loaded, no worries, current will be way under the rating.

Something like a small Honda generator with a knob that could be dialed back to 208 volts is one way to test this before going to all the trouble to construct it.
 
A motor made to run in 230 volts should never have less then 95% of nameplate voltages. So 230 × 0.95 = 218.5 volts so it should not be supplied by 208 volts. Too often have been in plants that had 208 volts and during hot summer days measured 190 volts at load side on motor starters. You could install a buck / boost transformer to raise the existing 208 volts to 230 volts.
 
garbo said:
A motor made to run in 230 volts should never have less then 95% of nameplate voltages. So 230 × 0.95 = 218.5 volts so it should not be supplied by 208 volts. Too often have been in plants that had 208 volts and during hot summer days measured 190 volts at load side on motor starters. You could install a buck / boost transformer to raise the existing 208 volts to 230 volts.
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and I thought it was +-10%
 
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