Generator breaker tripping - Xantrex charger at fault?

[SatyrTN]

Hi, all!

I have a Xantrex Trace inverter/charger that controls charging my battery bank from solar panels.  I also have a Titan 5500 diesel generator to use as backup.  Just recently, I've started having problems with the breaker on the generator tripping.

The situation is this: I start up the generator as usual.  After a set time (15 seconds), the charger kicks on to allow input from the AC2 input.  After a second or so, the breaker on the generator trips.

The system had been working fine all winter (though more warm-up time was required, sometimes up to a minute).  The only things that have changed in the past month are that I filled the generator with oil, since it was getting low, and (of course) the weather has warmed up.

Any ideas if there are settings on the Xantrex that may be causing the breaker?  Other ideas I could look into that might be causing it?  As it stands, my backup system is not available, so any help getting the system fixed would be greatly appreciated!
--SatyrTN

[Boss]

sounds like the same symptoms of a Trace 4024 I saw on Santa Fe Craigslist last week. Unfortunately the listing is gone already, because he had the estimate from Xantrex for replacing or repairing something he called an FET board, Symptoms were: charges from the PV, and inverter works, but it was tripping the breaker on the generator soon after the genset  started. 
Here is what is left from the ad:

Trace SW4024 inverter, needs repair - $750 (Santa Fe) Santa Fe NM
1998 trace inverter, 4000 watts, 24v. this inverter has been in service in a professionally-installed off-grid pv ...i'm a professional pv installer, who installed this inverter in a full system in 2002) to replace this inverter ..

[SatyrTN]

Just to give an update on the situation (in case anyone else runs into something similar)...

Turns out it's not the charger's fault, per se.

Our generator is over a year old, though it only has 220 hours runtime on it.  But we hadn't changed the oil in that entire time.  So, what seems to be happening - when the generator's not running at optimum speed (as in, it hasn't warmed up enough yet), the pull from the Xantrex charger causes it to go in to "overdrive" to make sure it's giving enough amps.  When it does that, it ramps up to somewhere around 25 amps, at least for a short time (a couple seconds).  That's enough time for the Xantrex charger to have a fit, and to cut off the input.  Which then throws the breaker on the generator.

Short answer - take care of your equipment and change the oil every once in a while

We've now changed the oil, and the generator still takes up to a minute or two to warm up (even in this spring's warm weather).  But once it has, everything works as it's supposed to.

Thanks, all!
--SatyrTN

[wpowokal]

I suspect from your description that the generator was unable to respond to the sudden load fast enough causing the frequency and voltage to drop below the inverter/charger specs.

It would be the warm up period more so than the oil change, at least you have solved your problem, thankfully I don't live in a cold climate.

allan

[dnix71]

A proper warm up is required no matter where you live. We have a 400KW Vovlo Penta out back of the shop for hurricane backup. It has to run for about 5 minutes before throwing the transfer switch. The engine needs to warm up, the oil needs to circulate and the field winding/core needs to saturate before you can expect stable full power output.

[SatyrTN]

Yeh, the warm up period helps, but doesn't solve the issue.  We've taken in the generator (everything seems to be fine) and the inverter (everything seems fine), so we *think* we've narrowed it down to the waveform generated by the Titan generator.  If the power generated is a dirty wave, the inverter may not be able to synch well, and therefore tripping the breaker.  I'm taking the generator to a shop next week and we'll see if that's the issue
--SatyrTN

[B529]

Yeh, the warm up period helps, but doesn't solve the issue.  We've taken in the generator (everything seems to be fine) and the inverter (everything seems fine), so we *think* we've narrowed it down to the waveform generated by the Titan generator.  If the power generated is a dirty wave, the inverter may not be able to synch well, and therefore tripping the breaker.  I'm taking the generator to a shop next week and we'll see if that's the issue
--SatyrTN

Do you have a AC frequency meter or access to one?

[hydrosun]

I'm not sure on your inverter, but some trace inverters have a setting for how long before connecting to the generator. They also have a setting for how high and how low the voltage can go before disconnecting. I think the default is 108 to 132 volts.  There is also a setting to limit the charging amps. Lowering that would limit the surge needed by the generator. It would also take longer to charge the batteries.
Chris

[madlabs]

I was having trouble with a Trace 2512 doing the  same thing. I tried lowering the charge amps and so on, to no avail. It turned out in the end that it was a crappy breaker on the generator. Replaced that and it's been fine since. Not too likely but worth a check if you remain stumped.

Jonathan

[SatyrTN]

Thanks to everyone that tried to help out with this one - we finally figured out the situation.  B529 had the right track - it turns out the generator was producing power that was pretty dirty.  Since we're using biodiesel, and the generator was made to use regular diesel, the speed of the motor was slightly off.  That dirty power would often cause the inverter to not accept it.

Took a lot of trips to different service shops, but it was worth it - the generator and inverter are now working together wonderfully

Thanks!
--Ian

[Madscientist267]

Leaves the question...

What did you do to fix it?

Use standard diesel? Or tune the engine to like bio instead...?

Seems like it wouldn't matter, but I can see myself asking the question down the road, might as well know the answer before I run into a problem...

?

 

[SatyrTN]

Tuned the generator - we'd much rather use B20 (or even home-made biodiesel - someday) than use the full diesel.  But evidently it was a really easy tuneup for the mechanic to do.
--Ian

[SparWeb]

Call me Johny-come-lately, but I just saw this for the first time.  The first thing that came to mind are the Inverter menu settings, not the generator, though it's good to see that you've sorted out the details with the generator's fuel conversion.
If you have a SW inverter (I don't see it identified in your post?) then in the menus you can set the max Amps the inverter will accept from the generator.
Excerpt from the SW manual:

Adjust the SET GEN (AC2) AMPS AC menu item located in the AC INPUTS (11) menu heading, to
the continuous output ability of the generator. This allows the generator support feature to function
correctly, preventing the generator from being overloaded. The generator's output should be de-rated
for altitude and if propane or natural gas is the power source. It is best to error on the low side for this
setting, or to experiment with higher settings after the system has been operational.

Since the AC2 (generator) has to be in synch with AC1 (grid or inverter's internal clock), there's only so much slop that can be allowed before the waveforms conflict with each other.  Since the generator is running at a speed corresponding to a mechanical set point, it can fluctuate with load, especially with rapid changes in load. 

If you've been having trouble with the Schneider/Xantrex/Trace websites (it would be a surprise if you weren't having trouble, let's put it that way) and can't find the instruction manual, I have a copy on my computer for the SW4024 that I can e-mail to you.