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Thread: Two speed motor - run on 230 3ph
07-31-2010, 08:07 AM #1
Two speed motor - run on 230 3ph
I have a Deckel mill with a dual speed (710/ 1425) motor
Six terminal posts are marked u1,v1,w1, and u2, v2,w2.
Is it possible to rewire this to run from a 230v output VFD or do I have to have a 415 output type
07-31-2010, 09:44 AM #2
Such "consequent pole" motors are necessarily single-voltage, as the windings are made in one continuous set, which are later distributed about the 36 slots (three sets, 120 degrees apart), and with taps placed at U1, V1, W1 and U2, V2, W2.
If the motor nameplate is marked 380, 400 or 415 volts (the three options for three-phase power in most of Europe), then your option is a 440/430/460 volt VFD which has had the appropriate parameter changed to match the voltage rating of the motor.
"Consequent pole", or "pole changing" motors, are designed for a single voltage, only, and a rewind is necessary to change the voltage.
07-31-2010, 05:03 PM #3
I was rather expecting that reply Peter. Sad but thanks anyway!
Not too much of a problem as I can buy a motor for £90 but such a shame to have no use for the original.
Any suggestions ?
08-07-2010, 09:14 AM #4
415v from 240v single-phase
Some older 415v 3-phase input inverters can be hacked to give 415(ish) out from 240v in, look for one which has two banks of reservoir capacitors after the input rectifier, if it has, see if the two banks are wired in series and again if so, you can take the 240v neutral line to the mid-point between the capacitor banks, apply phase voltage to one of the 3 phase inputs and Robert's your parent's sibling, a voltage doubler input that will fool it into thinking it's on 415v.
This is NOT a manufacturer-approved method, end of the world may ensue etc., but 415v input inverters are cheaper on Ebay than 240v anyway, and the more common larger sizes mean you can derate them the necessary 30% or so to allow for the added strain on the reservoir caps. If you're not sure of what you're doing, get a Grownup to help
If you're using a 2-speed motor with a VFD it's worth having some sort of interlock to de-energise the VFD when changing speeds, they get all huffy and spit out the magic smoke if the load's switched under power...
(with a 3-speed, 3-phase, 415v pole-switching motor to power from single-phase 240v...)