frequency control 3 phase motors

If you have a 3 phase 20 amp motor, with a frequency control starter on it and you run the motor with , say at a frequency of half the 60 cycle. The motor is then running at a lower speed. If you take a volt and amp reading first at the line of the starter , then at the load at the starter going to the motor. aprox what would the readings be? g.m.c.

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Do you own homework.

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As you reduce the frequency, the voltage also reduces. At half frequency, you should see half voltage. The VA input must almost equal the VA output, so the voltage ratio will equal the frequency ratio and the the current ratio will be the inverse.

Best regards, Mark.

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Mark Empson

depends on the type of motor, what characters the motot will have at X rpm. and what you want to do with it and if this is possible so back to the drawingboard more or less...

be carefull, sounds like a 6KVA motor

"gil" schreef in bericht news:zonNb.2058$

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You didn't say how you were measuring the current. With a clamp meter or ammeter, you will not get a true current reading on the output side of the inverter as this is 'chopped'. Most inveters provide you with an analog output to which you can connect a meter for a true reading.

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