Dual-Rated Motor

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charlie b

charlie b

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Given a 3-phase motor with a dual rating of 230/460V, if we change the power source from 240V to 480V, would this require the wiring to be reconfigured?
 
charlie b said:
Given a 3-phase motor with a dual rating of 230/460V, if we change the power source from 240V to 480V, would this require the wiring to be reconfigured?
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If you mean inside of the motor, yes. Inside of the motor peckerhead (or on the nameplate) there will be a diagram showing how the motor connections need to be changed.

But if you meant the external wiring, then no, just what dkidd said.
 
I have a question from the field for a project that was issued before my time. The persons involved are no longer working at this office. The drawing says to rewire the motor for 480V. It is not clear to me what was meant by that.
 
Jraef said:
If you mean inside of the motor, yes. Inside of the motor peckerhead (or on the nameplate) there will be a diagram showing how the motor connections need to be changed.
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Different connections for a 4% change of voltage???
 
Is the conduit and wire staying the same? Then you might need check the branch circuit wiring method is well bonded; 250.97 Bonding for over 250V to ground.
 
charlie b said:
Given a 3-phase motor with a dual rating of 230/460V, if we change the power source from 240V to 480V, would this require the wiring to be reconfigured?
Click to expand...
The answer to this question is yes the motor is connected delta for one voltage and star for the other voltage
 
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charlie b said:
I have a question from the field for a project that was issued before my time. The persons involved are no longer working at this office. The drawing says to rewire the motor for 480V. It is not clear to me what was meant by that.
Click to expand...
as i said before for the 460 V the connection would be star connection when 230v v is connected Delta
 
charlie b said:
I have a question from the field for a project that was issued before my time. The persons involved are no longer working at this office. The drawing says to rewire the motor for 480V. It is not clear to me what was meant by that.
Click to expand...

“reconnect” would have been a better way to describe what needs to be done instead of “rewire”.
 
Ainsley, your 3 links suggestion is, I think, for a wye to delta change. A 230/460 motor will either have 9 or 12 leads (most 9, 12 if configurable for wye-delta at either voltage).

For 230, a pair of windings are connected in parallel. for 460, that pair are connected in series. Look at page 10 of an example 10 HP motor I randomly selected, https://www.baldorvip.com/Product/InfoPacketExternal/?id=CEM3774T
 
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