MD84
Senior Member
- Location
- Stow, Ohio, USA
I was called in to replace a control power transformer on a 36Vdc forklift charger. The charger was originally setup for 208V. When the charger was reconfigured to 480V the CPT taps were not adjusted for the higher voltage. This smoked the CPT. I replaced the CPT.
After checking everything over I switched on the breaker. I quickly found that I had no voltage. The wires were not connected in the JB. I connected the wires and switched it on again. This time I had some voltage.
I had good voltage each phase to ground but did not have voltage a phase to c phase. The charger did work in this state. I am assuming that somehow the wires were mixed up in a JB upstream or in the panel and the two wires with no voltage happen to be the same phase.
My questions are:
1. How will this three-phase full wave rectifier react to having 0 volts across two poles?
2. What other scenarios could cause the 0 volts.
Thanks,
MD84
After checking everything over I switched on the breaker. I quickly found that I had no voltage. The wires were not connected in the JB. I connected the wires and switched it on again. This time I had some voltage.
I had good voltage each phase to ground but did not have voltage a phase to c phase. The charger did work in this state. I am assuming that somehow the wires were mixed up in a JB upstream or in the panel and the two wires with no voltage happen to be the same phase.
My questions are:
1. How will this three-phase full wave rectifier react to having 0 volts across two poles?
2. What other scenarios could cause the 0 volts.
Thanks,
MD84