Generators that work with SW4024

interd0ginterd0g Registered Users Posts: 7
Oddly enough I am an electrical engineer and used to represent Trace in Antigua, but I can't get this question answered by anyone still around at Trace or anywhere else.
I have run into trouble with generators failing to talk to a Trace SW series, with sometimes dramatic results when they try to go online.
One generator which came with the house (a portable with capacitor regulation) gets qualified by the Trace after the 45 secs warm up and then when the online relay closes bang! - generator output ceases and the Trace drops out. Doesn't matter how low you set the max generator current.
(Needless to say, I carefully check voltage and frequency continually)

A neighbor with a Honda i-type ( built in inverter and variable rpm.) - when it goes on line the Trace delivers curent back to IT, tripping the gensets output breaker.

Now I want to get a 6 kw gas generator for occasional back up against long hurricane outages which always go along with a week or two of overcast, hence minimal solar also.
But its hard to feel confident when Trace won't commit themselves and generator manufacturers at that level don't quote specifics on distortion.
In short, does anyone know of anything published on which generators might work? Or do you have an experience?


  • rplarryrplarry Solar Expert Posts: 203 ✭✭✭✭✭
    Re: Generators that work with SW4024

    I have 2 neighbors with the 4024, 1 uses a yamaha 5500w diesel and the other neighbor uses a Kubota 5000w diesel both work fine.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generators that work with SW4024

    Are you sure there's not something wrong with the inverter?
  • halfcrazyhalfcrazy Solar Expert Posts: 720 ✭✭✭
    Re: Generators that work with SW4024

    there is something amiss here. i would suspect a bad inverter
  • Ralph DayRalph Day Solar Expert Posts: 927 ✭✭✭✭
    Re: Generators that work with SW4024

    Sounds like the inverter to me too. My SW4048 had a bad 35amp breaker which caused much headache charging for the first year of operation. It would drop gen power, then pick it up and run fine, then drop it again...very frustrating. Xantrex of course, said it wasn't their product but the generator. The same thing happened with 3 generators, my own was the best of the bunch. (Best sine wave, best voltage and frequency regulation) They said if it wasn't charging properly it wouldn't be inverting properly either.

    Final result was lights out in December, the breaker failed, no charging or inverting. Once the part was replaced (the installer had a spare inverter for me) all has been fine. It's never the manufacturer's problem, it's something else..until absolute failure!

    Unless you have some strange wiring between the generator and inverter, assume it's the inverter's fault, but don't expect agreement from X company.

  • RCinFLARCinFLA Solar Expert Posts: 1,332 ✭✭✭
    Re: Generators that work with SW4024

    Sounds like there is something broke or miscalibrated with the phasing alignment process. The relays should not engage until the inverter closely matches the phase and voltage on the AC1 or AC2 inputs.

    Relay RY1 is the AC2 engage relay. Its 12vdc coil control is pin 33 on J1 going to control board.

    Relay RY2 is the AC1 engage relay. Its 12 vdc coil control is pin 34 on J1.

    You might disconnect the relay 12v control from actual relay so it always remains open. Monitor both AC2 and Inverter output waveforms on scope when control line pin says to engage relay (control line gets grounded to energize relay coil). Two waveforms should be syncronized at point where relay engages.

    Other involved items on power relay control board are the three small voltage sense transformers ( T4 is voltage sense for AC1, about 13.8vac on secondary with 120vac on primary, T8 is AC2 voltage sense.) The low voltage output from these transformers goes to control connector J1, AC1 sense to pin 3 & 4, AC2 sense to pin 1 & 2. Inverter output voltage sense transformer, T5 output goes to J1 pins 5 & 6.

    You can look at all these low voltage (13.8 vac) outputs to compare voltage and phasing if you have a scope available. It is relatively safe and accessable at the P1 connector on top of control board.

    This can all be done on the relay power board but the SW's are not very debug friendly due to its mechanical layout. Be careful!

    Other question does AC1 input work?
  • interd0ginterd0g Registered Users Posts: 7
    Re: Generators that work with SW4024

    Thanks for all the suggestions. I managed to borrow a couple of generators and it likes the Yamaha 6600DE and also a Honda 11kw twin cylinder gasoline genrator.
    They both have proper voltage regulators the standard brushless design.
    It still hates the old Groban although the Groban runs anything else OK. The Groban waveform also will not get past an industrial grade surge suppressor I have in line so The waveform must be terrible. I don't have a scope probe right now so I will look later.
    I read elsewhere that the capacitor regulation scheme ( common in ultra-cheap portables), although maintaining a pretty constant voltage as seen on an averaging multimeter, has about 30% harmonic distortion which might prevent co-operation with the inverter in the SW sync mode. Its a shame Trace/Xantrex never had an application note on this.
  • RCinFLARCinFLA Solar Expert Posts: 1,332 ✭✭✭
    Re: Generators that work with SW4024

    One item to watch for on generators is 'warbling' around the 60 Hz speed. Although the SW and SW+ inverters can run from 60 Hz +/- 6 Hz, the initial lock-on phasing process has trouble when the speed of generator (centered on 3600 rpm for single pole field generator) is wandering slightly at a modulation rate of couple of seconds.

    I have a Generac 15kW and when there is absolutely no load it will wobble in speed a little. A frequency meter reads a wander between 59 and 61 Hz. Sometimes my SW+'s have a little trouble locking onto the wandering speed even though the spread is well within the +/- 6 Hz range.

    The generator has electronic regulator and speed control. The engine throttle is controlled by a stepper motor. I am guessng the stepper motor step size resolution is likely the reason for the 'warble' when the carborator throttle plate is nearly closed at no-load condition on the generator. You can hear the warble just listening to the generator.

    It only happens at no-load and plugging in a light bulb to gen outlet makes it smooth right out.
  • Ralph DayRalph Day Solar Expert Posts: 927 ✭✭✭✭
    Re: Generators that work with SW4024

    A good idea to have a lightbulb always plugged in then. My old Simpower genset will act up if the electronics are damp or cold. The preheat (block heater) for the engine also has a 60watt incandescent bulb in the control box to warm the brains up (on a clock-type timer). Once the unit is running another bulb in the brain box runs all the time. Not too much heat, but enough to keep things happy in the damp and cold. No bulbs sometimes means no running, so an easy work-around.

    Whatever makes it work!:p

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