Forum Discussion

SteadyEddy's avatar
SteadyEddy
Explorer
Jul 26, 2017

No 120v from generator

I have a 2014 Coachmen Mirada 35DL, and have been using it regularly since new. With minor exceptions, all has been working fine. Today I wanted to exercise my onboard Onan 5500 generator which I regularly do every couple of months. After starting the generator normally, I went to run the A/C to give it some load and noticed that NO 120 volts was getting to MH outlets, microwave, TV, etc.... nothing.
So I hooked up my portable Progressive Industries 50PTC between the generator and the MH 50 amp Power plug. Restarted the generator and watched the PI unit display the voltages and amperages... both lines were normal at 120 volts and 60 hertz.
But inside the motor home there is no 120v.
Disconnecting generator and reconnecting 50 amp shore power, and all works normally. All circuit breakers in generator and MH panel are good.
So what gives? What inside the MH will not allow generator power to get through but will allow shore power...
M/H cable connected to shore power (50 amp) = Fine, 120v throughout MH
M/H cable connected to generator (50 amp) = NO 120v in MH
M/H cable connected via PI EMS to generator = EMS shows 120 volts (both legs) & no errors but NO 120 v power in MH.
I am totally baffled.

PS. I do NOT have a power inverter or an automatic generrator transfer switch.


Thanks for any input
Class A
  • garyemunson's avatar
    garyemunson
    Explorer II
    Jul 27, 2017
    On loose wires...be sure to check the terminals on your transfer switch once a year..they are notorious about loosing up.
  • SteadyEddy's avatar
    SteadyEddy
    Explorer
    Jul 27, 2017
    tropical36.. you are quite right. The amperes registered at 0 at that point.
    Not sure why I mentioned the "amperage" reading at all.
  • tropical36's avatar
    tropical36
    Explorer
    Jul 26, 2017
    steadyeddie wrote:
    Restarted the generator and watched the PI unit display the voltages and amperages...

    So how many amps and how is this possible with no load from the coach?
    Maybe I'm missing something here.
  • SteadyEddy's avatar
    SteadyEddy
    Explorer
    Jul 26, 2017
    OK.. thanks to all.
    Don AKA filadelfia wins the prize. After fooling with it some more, I found that one of the wires had worked loose in the motor home 50 amp plug, and certain ways the cord rested, the contact was either made or not.
    I took the plug apart and reconnected the wires, securing everything well and all is working now.
    I'm fortunate that the loose wire did not cause anything to short out... tested all appliances and A/C units and all seems fine.
    Thank you,
    Ed
  • dougrainer's avatar
    dougrainer
    Nomad
    Jul 26, 2017
    1. BOTH Genset breakers are ON and not tripped?
    2. When you state NO Auto Transfer, your model has a 50 amp receptacle in the Motorhome that you plug the 50 amp Shore Cord into it?
    3. FREQUENCY would be nice to know from the Genset.
    4. Also, at the 50 amp receptacle in the motorhome that the Shore Cord plugs too, what is the Voltage between each 120 leg and the Neutral? Doug
  • enblethen's avatar
    enblethen
    Nomad
    Jul 26, 2017
    Strange! Works hooked directly to shore power, guessing it is full 50 amp connection.
    Do you have an energy management system? What voltage is it set to?
  • SteadyEddy's avatar
    SteadyEddy
    Explorer
    Jul 26, 2017
    Thanks for suggestions...
    Have ruled out the EMS because problem exists even with direct connect between MH power cable and Generator, bypassing the EMS.
    Have tried "jiggling" power cord when connected to generator, but no change.
  • enblethen's avatar
    enblethen
    Nomad
    Jul 26, 2017
    It is possible that the Progressive unit is not seeing a bond between the neutral and ground. Look at the Progressive manual for this.
    Some gensets need to have a jumper to lie to the EMS.
    A 15/20 amp cord body with a jumper between the neutral and ground should correct issue as it does on Honda gensets.
  • filadelfia's avatar
    filadelfia
    Explorer
    Jul 26, 2017
    Just a guess, maybe your shore power cord has broken conductors and only makes contact in certain positions.

    Good luck Don

About Motorhome Group

38,707 PostsLatest Activity: Jan 05, 2014