Re: [CAD_CAM_EDM_DRO] Inverters/phase converters

Voltages are as follows (L3 is the generated leg):

Phase converter - no load
L1-L2 244V
L1-L3 270V
L2-L3 252V

Phase converter - 3hp motor running
L1-L2 243V
L1-L3 232V
L2-L3 235V

I suspect the voltage at L1-L3 and L2-L3 would drop more if the motor were
under load. The converter is much quieter when a motor is connected,
indicating better phase balance.

My experimenting will involve programming the VFD and trajectory card - the
motor will not be under load at this stage. I just want to make sure I know
what buttons to push before I turn off and remove parts from my client's
main source of income.

We are going with Baldor stuff this time around because the vendor promised
to assist with programming. Next time I hope to use Hitachi and save about
$1200.

Doug

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First question is how high is high? and what does it settle down to? Actual
voltages are important. I have run a VFD on a rotary and had no problems.
If the rotary generated leg comes within 20 - 30 volts of the mains when the
other motor is running, you should not have any problems and to be safe I
would have the other motor running. The voltage measurement that I am
talking about is measuring from leg to leg (L1 to L2, L2 to L3, L3 to L1)
measuring from L1 and L2 to ground (assuming L1 and L2 are the mains) should
give a reading of 120 volts AC. Measuring L3 to ground on the other hand
could read 200 or higher. What is important is the leg to leg voltage.
Darrell

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