View Single Post
  #3   Report Post  
Gary Coffman
 
Posts: n/a
Default Voltage on Phase Converter

On 14 Aug 2003 00:50:46 -0700, (Steve) wrote:
jim rozen wrote in message ...
In article , Steve says...

I checked the voltage on my phase converter (3HP 3Phase Baldor)today
and got 122v,122v,and 180v on the wild leg. Is 120v all I should be
getting on the 2 lines from the 220v line from the breaker box even
after they are fed through he converter? I thought that the converter
would boost these a little bit. Thanks for the help. -Steve


I think you are measuring the voltages incorrectly. You
need to measure line to line, three ways, not line to ground.
The 120 volt number you mention implies that you are measuring
line to ground.


Thanks Jim. Now the question is: How do I set up my voltmeter to
measure line to line? The same way that I measured line to ground? Or
is there a different setting on the voltmeter I should use. Thanks
again, Steve.


Just put one probe on one motor terminal, the other probe on another.
Since you're measuring AC, it doesn't matter which probe goes where.
Remember, 3 ph doesn't involve ground, so measurements to ground
are essentially worthless.

A to C (L1/T1 to L2/T3) should be 240 volts.
A to B (T1 to T2) should be 240 volts.
B to C (T2 to T3) should be 240 volts.

Unless the converter is tuned perfectly, the 3 voltages won't be
exactly the same. But if they're within 10%, they'll be fine. If they
aren't, then you need to adjust the tuning capacitor values until
they are.

Gary