I am stumped! Here's the scenario. Two 56" 120V industrial ceilng fans in parallel. One speed control. These two fans are on phase one of a three phase system. Phase two and three are lighting circuits. All small loads. The fan closest to the rheostat drops out of service. Technician checks and the motor has been fried. Checks voltage while second fan is still running. Line to neutral reads 140V on load side of rheostat. Why? When the switch is in the "high" setting or the "low" setting voltage is 120V. When the switch is adjusted between these settings voltage reads 140V. Again why? I can't explain it to my staff cuz I am at a loss.
