olly
Senior Member
- Location
- Berthoud, Colorado
- Occupation
- Master Electrician
I have a really old motor the name plate says 230/460. Can a 277/480 transformer feed this motor?
230/460 motor
- Thread starter olly
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LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
I would guess the 277v is too high for 230v, but the 480v is perfect for the 460v.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
On a 480Y277V system, the 277V is the phase to neutral voltage, it would not apply to a 3 phase motor at all.
Motor voltage ratings are always lower that standard line voltage ratings, because it is assumed that there will be a voltage drop between the transformer and the motor terminals. 460V is the standard "Utilization Voltage" rating of a motor intended to operate on a "Service Voltage" of 480V. The Service Voltage from the utility can vary by +-5%, the motor is designed around +-10% of the Utilization Voltage. That way a 480V service can drop to 456V or rise to 504V, but the motor can handle down to 414V up to 506V, so no problem.
Motor voltage ratings are always lower that standard line voltage ratings, because it is assumed that there will be a voltage drop between the transformer and the motor terminals. 460V is the standard "Utilization Voltage" rating of a motor intended to operate on a "Service Voltage" of 480V. The Service Voltage from the utility can vary by +-5%, the motor is designed around +-10% of the Utilization Voltage. That way a 480V service can drop to 456V or rise to 504V, but the motor can handle down to 414V up to 506V, so no problem.
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