50 amp electrical issue
I have a strange issue going on with the power. I have a 50 amp RV with a Progressive Industries EMS and also a Hughes Auto Transformer when needed. As long as the campground does not have many ca...
Forum Discussion
Ok let me do the technical bit, As I said I HAVE SEEN THIS in personal life.
The power is supplied by a 240 volt center tapped transformer.. 120-0-120 or 240 volts across the entire winding.
Now, let's say you have your A/Cs on, and lets, just for chatting sake say the FRONT A/C is on L-1 and the rear on L-2 Other loads are either also balanced or off.. Current flows between L-1 and L-2.. since the two legs are evenly balanced NO CURRENT AT ALL flows in the neutral. Voltages remain 120-0-120.
Now let's assume one of the A/C's shuts off,,, or if it was off the compressor starts. Suddenly that leg is carrying a lot less/more current.
Now the neutral carries the DIFFERENCE between L-1 and L-2 and you basically do not notice much in the way of voltage changes.
Next we do the same thing but with an OPEN neutral.. Now the Neutral can not carry current.
Thus the apparent "Tap" moves.. ONE leg goes UP in voltage, while the other goes down, the total L-1 to L-2 does not change, but the "Zero point" moves so instead of 120-120 you may well have 150-90 or the other way around. NOT A GOOD THING.
Blew a bunch of light bulbs in my house, and reset the coputer (on the low side) till I got 'em out to look at it.. I had two problems.. (Safety ground was not that great either) They fixed the ground and that tamed it.. Then they fixed the neutral and that eliminated it.
The power is supplied by a 240 volt center tapped transformer.. 120-0-120 or 240 volts across the entire winding.
Now, let's say you have your A/Cs on, and lets, just for chatting sake say the FRONT A/C is on L-1 and the rear on L-2 Other loads are either also balanced or off.. Current flows between L-1 and L-2.. since the two legs are evenly balanced NO CURRENT AT ALL flows in the neutral. Voltages remain 120-0-120.
Now let's assume one of the A/C's shuts off,,, or if it was off the compressor starts. Suddenly that leg is carrying a lot less/more current.
Now the neutral carries the DIFFERENCE between L-1 and L-2 and you basically do not notice much in the way of voltage changes.
Next we do the same thing but with an OPEN neutral.. Now the Neutral can not carry current.
Thus the apparent "Tap" moves.. ONE leg goes UP in voltage, while the other goes down, the total L-1 to L-2 does not change, but the "Zero point" moves so instead of 120-120 you may well have 150-90 or the other way around. NOT A GOOD THING.
Blew a bunch of light bulbs in my house, and reset the coputer (on the low side) till I got 'em out to look at it.. I had two problems.. (Safety ground was not that great either) They fixed the ground and that tamed it.. Then they fixed the neutral and that eliminated it.
