460VAC 60Hz Motor on 400VAC 60Hz? 1

Hello,

Motor rated power and torque (output) is directly proportional to the square of the voltage. If you use a 460Vac motor on a 400Vac network, it won't be able to develop the "rated torque", and instead, will develop (400/460)^2 = 75.6% of it.

What will happen depends on the mechanical load connected to the motor. Possible scenarios:

1. Motor starting torque is not enough to accelerate the mechanical load => Motor will fail to start (luckily protections will trip)
2. Motor start ok but it cannot develop enough torque to move the mechanical load at the required speed. Probable the motor will trip due to overload
3. Motor start ok and develop enough torque to move the mechanical load (the most unlikely scenario)

Regards,
Juan

JBC
.......
"The more I read, the more I acquire, the more certain I am that I know nothing"

A lot of Juan's "trips" could easily be replaced with 'burn-outs'.

No you cannot use a 460V motor in 400V same frequency service.

However you can use a transformer to boost the 400 to 460 and everything will work just fine.

Keith Cress
kcress -

In Canada a common supply voltage is 600 volts. In many areas 480 Volts is not available unless the customer buys his own transformer(s).
Conversion between 480 Volts and 600 Volts is relatively common. Typically with auto-transformers, two in open delta or three in wye.
The open delta connection is preferred because of the easier availability of the proper voltage ratings.
Open delta works with a 480:120 Volt transformer.
A wye connection needs 277:70 Volt transformers. Not an off the shelf item.
I have seen 480 Volt generators boosted up to 600 Volts to match plant voltage.
I have seen 600 Volts dropped to 480 Volts to power rental equipment.
I have seen an instance where 600 Volts was dropped to 480 Volts to supply a 480 Volt plant that was moved into 600 Volt territory, and then boosted back up to 600 Volts to supply a new, 600 Volt machine.
I have also seen 480 Volts boosted up to 600 Volts and then dropped back down to 480 Volts.
For 400 Volts to 460 Volts, I may use three 230:32 Volt transformers in wye.
That will give a rating of:
230V x 1.73 = 398 Volts in. 0.5% error
and
32V + 230V = 262 Volts x 1.73 = 454 Volts out. 1.3% error.
BUT
400 Volts into the 398 Volt transformer will give 457.5 Volts out.
Close enough for 99.0?% of applications.
If the transformers have adjustment taps you can get even closer.
How close you need to be depends on the load.

Bill
--------------------
"Why not the best?"
Jimmy Carter

Where are you finding 400V 60Hz? It’s not a standard voltage anywhere.



" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

Couple years ago we have built machine for Saudi Arabia. It was 3 phase 380V, 60Hz.

PaulBr