Electrical Manual
VM16,17,24,25,30 Sigma2 W/M5
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Transformer Connection Alert
***** CAUTION *****
DRIVES WILL BE DAMAGED BY INCORRECT POWER CONNECTION
Disconnect transformer entirely from power supply.
Check resistance between transformer ground wire and each secondary leg.
If resistance is more than 1 or 2 ohms, then the transformer ground wire is not
connected to a neutral point within the secondary windings.
or
Disconnect transformer entirely from power supply.
Remove transformer cover and follow transformer ground wire to determine if it is
merely a case ground or if it actually goes to a neutral point within the secondary
windings.
or
Check voltages between each secondary leg and ground.
If they are not equal, the secondary windings are “floating” with respect to ground.
THE GROUND WIRE GOING INTO THE MACHINE MUST BE CONNECTED
TO A NEUTRAL POINT WITHIN THE SECONDARY WINDINGS
AND TO EARTH GROUND.
The secondary windings must be grounded.
Voltages between each secondary leg and ground should be equal, half the voltage
between secondary legs.