Generator Issue

[mikedee]

We have a PowerTech PTSMH 17.5 Genset and have the following problem. The generator motor starts and runs perfect. 20 seconds or so go by the the transfer relay latches, and voltage is 117 on each leg. After the inverters lock on charge everything works great for about 40-50 sec.

After the +/-40 sec. then the generator quits making voltage, the relay drops and no power. You can restart the generator in a 3 min. and it does it again.

Any help would be great.

[Alek&Lucia]

Mike,

How is your oil level in the generator ?

Alek

[mikedee]

Oil is correct, as is coolant. The engine runs fine, when the power stops it is like the engine has been unloaded. Could it be dropping the exciter field?

[phorner]

Does your generator have an auto shut-down feature when the batteries are charged? I had a similar situation in a different coach. The generator would fire up and run perfectly until just after the transfer switch activated. It would then sut down.

As I finally realized, the generator was shutting down because the batteries were fully charged, and I had to re-program the inverter/charger remote panel to turn off that feature.

Hope this helps...

[nrhareiner]

Just a quick question. Does the generator actually stop, or does it continue to run, but not produce any electricity?

[mikedee]

The engine runs and keeps running, just the AC power drops. I took off the lid on the power control box and was able to look at the parts with a mirror.

I wiggled all the wires and the diodes and guess what, work likes new. We will see how long it lasts. I am going to have a generator shop in Modesto shake it out.

I will post the results.

[gmcbuffalo]

Mike a call to powertech in Florida should be your first step. Tech services. They can walk you through several trouble shooting steps. Sounds like something in the generator side of the system gone bad.
GregM

[Jon Wehrenberg]

Mike,

I have zero knowledge of generators, but from your description I think your guess is right on the money.

It sounds like you have the equivalent of an alternator field wire intermittently supplying power. That loose connection opens the circuit dropping the generator off line. Somebody that knows generators can probably find the glitch in minutes.

[Jeff Bayley]

I have the same gen set. It could be a turn of the fine screw on the volatage regulator or a new voltage regulator which is about $150 I recall. I change and put the old one away as a back up. There are also some relay's in there. You could take each of the 3 or 4 regulators connections off (one at a time so not to confuse proper replacment) and check for corrosion or if connection tight enough. Mabye put some contact enhancer. It could be working ok for a while until the heat on one of the poor connections get's sufficient to take a dive for a while. A dremel tool with a miniture sanding bit could best clean the terminals on the 3 or 4 relays as well as the interconnects that attach to them or if corroded, dremel brush the relays and if enough slack, cut and put new matching female connectors on the leads leading into the relays. Look inside the control box (where these relay's are) and look for any burnt spots. Mine was a bad ground about a year ago and yes, a generator guy figured all this out for me but now I know that could be a possible culprit.

[adamdegraff]

I had a similar problem. Took it to CK power in St. Louis at the suggestion of PowerTech. My diode ring was loose and therefore burned up a little bit. The "little bit" part was why it worked a "little bit." New diode ring, and a new voltage regulator since the burned up diode ring likely hurt the regulator. $300 in parts, give or take. Works great now and, best part about it, is the tech who repaired it let me watch the whole set of repairs, teaching me along the way, and was a really nice guy as well. Made a new friend, and now could do the repair myself if wanted to. If you think this might be your problem, feel free to email me directly and I can talk you through the diagnosis.

Adam

[gmcbuffalo]

Adam
I would write the diagnosis steps down, a few years from now when you get that call you may not remember. I once knew how to bypass some of the function in the controller to test it, but now I would have to relearn the whole thing again. Did write it down.
GregM

[Joe Cannarozzi]

I had to remove my generator last year cause it stopped generating. When it was fixed the repair shop told me it was very dirty and that it just needed to be flashed and it was now fine. The way I understood it the magnets lost polarity??????? They put an external terminal off the rectifier so if it happened again I could do it without removing and disassembling it.

It had about 4500 hours when this occurred. It now is around a couple of hundred hours down the road and not only did I have to flash it again but when I did it only generated for around 1/2 hr or so then the voltage dropped severely and I was up shutting everything down before doing damage.

The unit is not set in sideways but deep-wise like a Liberty so I know I'm gonna have to pull it again to service it but does anyone want to take a guess as to what the heck is going on? The Kabota end of it runs like a top. It is a 15K and Universal has their name on the power end of it.

[truk4u]

Joe,

Could it be a regulator issue?

[Joe Cannarozzi]

I don't have a clue that's why i'm askin.

[JIM CHALOUPKA]

Check the slip rings and brushes. They should be smooth and not pitted, and clean. The brushes should make good contact and not be arcing.

This is just general knowledge that you will have to apply to your specific unit.

Some generators have a small fuse somewhere in/at the generator.

JIM

[dalej]

Joe, aside from the generator issue, how does it feel to be back in the bus again. It had been awhile hadn't it?

[gmcbuffalo]

Joe
I have a PowerTech and there is a small plate of electronics on the wall separating the motor from the generator part, It' called a rectifier, regulator or something. If it is bad the you don't make electricity and then the motor will shut down. Take it off and look at the backside see if it is burnt out. The PowerTech technicians were able to tell me what wire to remove on it to troubleshoot it, to tell if it is bad. I was in Quartzite when this happen to me and they sent me a new one after the troubleshooting steps. I have had no issues since then. These generators are made so that if no electricity is being made they will shut down. I would look at this electronic conpoenet first
Greg

[Joe Cannarozzi]

Greg this is a 25year old gen and it has no modern electronic anything.

Spoke with the fellow who worked on it today and he suspects it is a brush that is hanging.

Good guess Jimbo.