Cheating with inverter

[mick41zxr]

Not wanting to hijack previous thread, I though it would be better to post questions to a new one.

Eldon_Joh mentioned in Spumco's thread (https://www.cnczone.com/forums/spind...duction-2.html), that you could re-lace an induction motor to run on 110v
then use the VFD to get an increased torque range.

Can the same thing be done using a 380v inverter with a 220/415V motor wired in delta configuration.
i.e. 4 pole motor wired in delta would have a name plate 1425rpm at 50Hz (Aus) at 220V, below 50Hz constant torque, above constant power. However as you approach speeds to mill aluminum the torque of the motor is significantly de-rated.
by setting the inverter to name plate to 2560rpm at 90Hz at 400V the constant torque curve is extended by maintaining the V/F ratio & the effective torque at overspeed is extended?
a) Has anyone done this?
b) Would this significantly effect the motor if its insulation rating is high enough (inverter rated class F or H)?

Thanks,
Michael

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• Inverter

[mactec54]

Not wanting to hijack previous thread, I though it would be better to post questions to a new one.

Eldon_Joh mentioned in Spumco's thread (https://www.cnczone.com/forums/spind...duction-2.html), that you could re-lace an induction motor to run on 110v
then use the VFD to get an increased torque range.

Can the same thing be done using a 380v inverter with a 220/415V motor wired in delta configuration.
i.e. 4 pole motor wired in delta would have a name plate 1425rpm at 50Hz (Aus) at 220V, below 50Hz constant torque, above constant power. However as you approach speeds to mill aluminum the torque of the motor is significantly de-rated.
by setting the inverter to name plate to 2560rpm at 90Hz at 400V the constant torque curve is extended by maintaining the V/F ratio & the effective torque at overspeed is extended?
a) Has anyone done this?
b) Would this significantly effect the motor if its insulation rating is high enough (inverter rated class F or H)?

Thanks,
Michael

And kangaroos lay eggs, Eldon has his head in the clouds

[ericks]

If you have a four pole 220/415V motor and use a 380V drive then you will only connect the motor in delta. Going over 50Hz you will start losing torque.....no getting away from this. If your motor can still run without stalling at your load then you should be okay. I have seen four pole motors run at 100Hz for years without issues.