In article ,
Charles A. Sherwood wrote:
Are the motors truly in parallel? As in; all three legs of one motor
connected to all three legs of the other motor? If so, you should see some

They are both on the same contactor and start at the same time.
However they are connected together before the overload controls.
One contactor suppling power to seperate "heaters" for each motor.
The third wire of the static converter connects to the third
wire of the motors through the heaters. Seems like the logical
way to wire it (at least to me).

I could connect the third legs together before the heaters, but
I really don't think that would make any difference.

I see no current in the third leg with a clamp on ampmeter after
the motors have started. The voltage in the third leg is 208 and 224
with respect to the other two legs. I guess there is no current because
the voltage is low.

Where are you applying the clamp-on ammeter? If between the
junction of the two motors' wires and the static converter, there
*should* be no current once the motors are started.

However, if you clamp around one or the other of the motors, you
should see some current at least. (Mostly the amount would be based on
the horsepower and the loading of the smaller motor.) Perhaps if both
motors are equally lightly loaded, they are each generating about the
same voltage for the third phase, and as a result, are generating very
little current between them. Put a serious load on one motor or the
other and see whether there is a visible upswing in the current.

Good Luck,
DoN.

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