[Jerre122]

What would the effect be when your connect a synchronous servomotor, built for 460V 60Hz 3 phase with 380V 50Hz 3 phase?

Would there be any negative effects for the lifetime of the motor?
What other effects would there be?

[Al_The_Man]

When you say connect 380v 3 phase, I assume you are talking into the drive? If direct to the motor the result would be at least the applicable drop in rpm, if synchronous then the motor rpm is relative to the applied frequency.
But if you are talking a servo motor, it is very rare for the applied voltage and frequency to be fixed?
More Information needed!
Al.

[Jerre122]

It's directly into the motor. 460V is what it says on the motor and in documentation.
Btw, I'm talking about this motor: Allen-Bradley-7032-05-4102 | hopmachines.nl.

[Al_The_Man]

That is a servo motor they require some kind of commutation system, also placing it on 3 phase supply direct at 50/60 would only result in 375rpm as this is most likely an 8 pole motor.
If you obtain the right drive, they are usually flexible to some extent as to the applied voltage.
Al.

[Jerre122]

I understand that the driver will change the frequency and voltage. But the voltage will never be 460V only 380V max. What will be the effect of this, just a power loss like in a normal induction motor, or will the motor not work at all?

Since the speed changes with the frequency, i suppose there will be a loss of torque?

[mike_Kilroy]

the ONLY effects will be:

1) your max speed capability MAY BE reduced by up to 380/460 or be 82% of rating on 460v.
2) POSSIBLY - if the max HP point on this particular motor is at 460v max speed, then, yes, the max continuous HP rating will be reduced directly by the same ratio. But most likely the max HP point is NOT at the max speed point on the motor so it likely will NOT be reduced.

NO negative effects to motor life, heat, etc. NONE. There is NO LOSS OF TORQUE. The link you provided did not get me to a motor speed torque curve or motor specs so I had to guess on #2 above. Even #1 above may not need to be true: a lot of times a motors Kb rating is such that it will still reach max speed at 380v instead of 460 - depends on the particular motor. There is NO derating other than loosing top speed on a servo motor.

[Al_The_Man]

My question is, If you intend running this off of 50hz direct, if in fact it will run satisfactorily at all without the usuall commutation, is how is 750 fixed rpm going to be that useful?
My previous number of 375rpm was in error, but I am very sure these particular motors are 8 pole.
Al.

[Jerre122]

My answer of connecting the motor directly to 50Hz was an error made by me.
It will go via the driver.

[Jerre122]

I have found some 2.1kW servomotors who're cheaper than their 1.5kW version.
Do you know if an under powered servo driver can control a, for that driver, overpowered servomotor?

That is, if I have a servo driver rated 1.5kW and hook it up to the 2.1kW servomotor, will things still work okay?
What effect would this have on the performance of the motor?

Because the 2.1kW servomotor is cheaper than the 1.5kW servomotor I actually need, using an under powered servo driver might be worth it (providing it works).

[Al_The_Man]

Usually you can set the current limit and other parameter to accommodate the larger motor, you may find it restrictive as to acceleration demands etc.
A lot depends on the demands of the particular operation.
Al.