Maker Pro
Maker Pro

frequency control 3 phase motors

G

gil

Jan 1, 1970
0
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.
 
M

Mark Empson

Jan 1, 1970
0
gil said:
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.
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.
http://www.lmphotonics.com
 
C

cuno

Jan 1, 1970
0
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
 
R

ripper

Jan 1, 1970
0
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.
 
Top