04-28-2013, 05:55 PM
Hi Tom,
Nice post. It is an easy misconception to think a 20A breaker trips right at 20 amps. Seems logical doesn't it. I wish I thought Chester's problems had anything to do with the breaker, but I don't. How he ever had 10 amps breakers in there I will never understand. It says all over the documentation and on the front of the A/C itself that each circuit requires a 20 amp breaker. But, we are beyond the easy fix now and into a more difficult problem.
Just for a recap - the control board with all its problems has very different results on the system than Chester is experiencing. When lands and relays and connectors fail on the board, the result is the voltage is not delivered to the motor and the motor just doesn't run when it is supposed to. The sad thing is this testing and high amps he is reporting will do no good at all to the control board, and could easily result in damage to the board. None of the switching components on that board are rated for the currents reported. I am worried about that.
Back to your primer on CBs. Locked rotor current and starting current are pretty much the same thing when voltage is first applied to a motor. My experience says at least 3 times normal running current, and often more. It seems to me that the only way these high currents might exist is through locked rotor on a motor. I do not believe that either of the fan motors not running could cause the compressor motor to produce such currents in the short time things stay on.
I will post a document with the wiring diagram and schematic. The wiring diagram will show what each connector goes to and where one would clamp wires to read the current one motor at a time.
But as I said, I am reluctant to recommend more testing as I fear for the circuit board. I have really only one last suggestion before I think it would be prudent to pull the unit from the coach to see what is going on. That is, replace the starting capacitors for all the motors. This can be done without removing the unit and actually might be successful if one of the motors is in locked rotor due to not starting up.
Nice post. It is an easy misconception to think a 20A breaker trips right at 20 amps. Seems logical doesn't it. I wish I thought Chester's problems had anything to do with the breaker, but I don't. How he ever had 10 amps breakers in there I will never understand. It says all over the documentation and on the front of the A/C itself that each circuit requires a 20 amp breaker. But, we are beyond the easy fix now and into a more difficult problem.
Just for a recap - the control board with all its problems has very different results on the system than Chester is experiencing. When lands and relays and connectors fail on the board, the result is the voltage is not delivered to the motor and the motor just doesn't run when it is supposed to. The sad thing is this testing and high amps he is reporting will do no good at all to the control board, and could easily result in damage to the board. None of the switching components on that board are rated for the currents reported. I am worried about that.
Back to your primer on CBs. Locked rotor current and starting current are pretty much the same thing when voltage is first applied to a motor. My experience says at least 3 times normal running current, and often more. It seems to me that the only way these high currents might exist is through locked rotor on a motor. I do not believe that either of the fan motors not running could cause the compressor motor to produce such currents in the short time things stay on.
I will post a document with the wiring diagram and schematic. The wiring diagram will show what each connector goes to and where one would clamp wires to read the current one motor at a time.
But as I said, I am reluctant to recommend more testing as I fear for the circuit board. I have really only one last suggestion before I think it would be prudent to pull the unit from the coach to see what is going on. That is, replace the starting capacitors for all the motors. This can be done without removing the unit and actually might be successful if one of the motors is in locked rotor due to not starting up.
Russ White
2016 Winnebago Vista LX 30T
#530 ( Sold )
1999 45' Double Slide - Factory upgrade 2004