Dead Generator

[Stephen1]

My old Subaru Generator has served me well for the 10 years. I am the 3rd owner. It has run for our 2 power outages of 1 week each this winter. I fired it up last night for another power outage and it produced power for 3 hours then it quite producing power, engine was purring nicely. I put the meter on the 120 volt outlets and only shows 1.12 volts.
What else should I look for ?
Or is it time for a new Jenny?

[Magicman]

Running and quit producing power sorta indicates that a connection is loose.  You will not know until you disassemble.  Could be an internal breaker, etc. that overheated. 

[Hilltop366]

I would check the brushes too. Sometimes they stick sometimes worn out.

[SawyerTed]

I had and old Coleman generator that had an exciter that created the magnetic field for the main generator.   If it didn't work the generator lost out put.  

There were contacts on the housing that occasionally needed a 6 volt battery connected to re-excite the circuit.   

It would be worth checking before tearing it down. 

[Old Greenhorn]

There are MANY things that can cause your issue with several major and simple ones already mentioned. Another is that many of those generators have some large wound resistors in them that can fail over time. They are also a simple parts swap out once you expose and test them.
 With all the stuff already mentioned here you have a good shot, statistically of figuring it out. If that doesn't work, you can always remove that half of the machine and take it to a electric motor/alternator shop and they can generally troubleshoot it on the bench.

 At least it failed at the end of the winter and not in November.

[Larry]

What Ted described in his post is called "flashing the generator". Do a google for a description.

A simple process that should be done before getting serious.

[Stephen1]

The generator is a power matic and I was able to find out it is partnered with generac now. I contacted a dealer/service center  near by who told me he can not get parts anymore for that unit. He suggested I pull and inspect the brushes  which I will do after lunch today. Along with the other suggestions. 

[Magicman]

I had a Kohler in a motorhome that used the 12v cranking battery to excite and then after the engine started a relay operated to transfer the excite voltage to self excite.  Problem was a dirty contact on the relay.  

If your control board has (a) relay(s), you could try popping the cover off and carefully clean the contacts.

[YellowHammer]

I was going to suggest the same thing, open the cover, disconnect the brushes, pull them, check the slip ring, it should be shiny, then check the windings with an ohmmeter, they should read closed to each pair, all about the same resistance reading, but not shorted to ground and generally about 2 or 3 ohms, or whatever your manual says, then check the continuity of the wires on the voltage regulator.  There may be a diagram on the cover.

The Generac guys here charges $450 per half day, and pretty worthless unless they can hook their computer up to it.  I've had to do all the trouble shooting myself, because I have an older 80Kw unit that they "don't work on."

I'm not familiar with your generator, but are there no indicator lights other than the voltage reading?

I'm surprised the engine is not throttling erratically, or pegged at full throttle, or not running.  It should be sensing the low voltage and be trying to correct, and in this case with voltage that low, should be at wide open throttle, and then cycling, then shutting down.  The fuel controller is dead or is somehow not reacting to the low voltage, but it's equally important to know that is sensing engine speed also, because engine speed, or RPM, sets the output frequency, which should always be 60Hz.  For example, my engine in my generator must run at 1800 RPM at all times, to produce 60 Hz at all load conditions.  So the fuel controller, sometimes called a "governor" is closed loop on both frequency as well as voltage.  I assume you are looking at the onboard display for the voltage reading, but equally important it should show or you should measure the frequency of the output voltage with your meter.  It should be 60Hz at all times and all throttle settings.  If it's not, then there is another problem, because most generators will have an emergency trip if the output voltage frequency gets more than a couple percent off 60Hz, because that will burn up the equipment it supposed to be powering.  So that's why I'm surprised your engine is even running.  On a commercial generator, a low voltage sense that bad would automatically shut down the engine.  Since yours is still running, there may be a safety trip that has been thrown and the engine is just running open loop, or it is convinced it is running correctly and there is a component interrupting the power to the plug.. 

If you are good with an oscilloscope, you can simply hook to the windings and measure the frequency and output of each winding, before it goes to the voltage controller.  Your multimeter may also have a frequency measuring mode.  Also, if you have a timing light, you can put that on sparklug #1 and directly measure engine RPM.

The best case is the generator is actually outputting 60Hz, 220V (or whatever voltage its rated for) out of the regulator, and the fuel controller is running perfectly, the generator is running perfectly, and as some are saying, it's just a downstream relay or contact that needs to closed to direct the power to the front panel and plug.  That would explain why the generator motor is running smoothly, it is actually producing the correct voltage at the correct frequency.  If so, you can go find out where it is being disconnected.   

Other than blind hogging it, and just checking everything, which is a good idea if you are lucky, it may be a loose wire, but it would take a little instrumentation to figure out where. 

There are LOTS of pretty good videos on the YouTube concerning generator troubleshooting, I watched pretty much all of them over the years fixing mine.   

 

   

[jcbrotz]

I may have missed it posted before this,but before you tear into the hard stuff definitely test the diode. small and very important piece in your genny

[Stephen1]

Geese Robert, I can barely work the voltage meter. I almost got the brushes out of the regulator. I need to pull more covers apart to get to them fully.  I  get to look at that more this weekend.
I was also dealling with my old bobcat which blew the hydraulic rad cooler. Spewing oil every where, I got the rad out and its off to the rad repair shop. 
Always something! But then we wouldn't be alive if we didn't have challenges. 

[wuddy777]

If you do end up replacing the whole thing, I'd skip the off-brand gamble and go with something like the Westinghouse iGen4500. Remote start, quiet, and crazy fuel efficient, perfect backup if your power drops every winter like clockwork.

[Stephen1]

Update, I was able to get the brushes out and no one carries parts for this old generator. Cathy has decide She needs a new generator. Electric start for sure maybe even a remote start.  
I would like at least a 5K generator, and I'm thinking  7.5K would be ideal. especially if I have guests in my Log Cabin B&B . 

My question is do I need the investor generator? 

I was able to run the house during the 2  1 week power outages no problems. 

[scsmith42]

I've lost count of how many generators I have here on the farm, I think it's around eight or nine. One of them is a Honda EU 6500i inverter generator.

The benefit of the inverter is lower fuel consumption when you operate for an extended time under partial loads. Some of the higher quality models do a better job of managing the harmonic distortion too.

Most of the rest of my generators are diesel and I can't think of a single instance where we had any problems with any electronics due to a generator issue.  Most of mine are 1800 RPM models but I do have a Q 3600 RPM.

Regarding your problem, why don't you post a photo of your current brushes and a number of us can share our thoughts on if they are bad or not. Typically when a brush goes bad it's either worn all the way out, or it's dirty and sticking in it's slide, or the spring has lost tension.

I have had generators developed sporadic voltage problems in the past due to a connector that cracked into. The connector was still occasionally making contact so the voltage drop was sporadic but that was found by simply using good old eyeballs and feeling around inside the generator and tracing wires.

[SawyerTed]

A couple of other inverter generator features are low sound levels, auto idle down during low demand  and cleaner power.   

[Nebraska]

If you have an Airbnb that would get powered off of this unit as well this is a deductible business expense is'nt it? Therefore it may be worthwhile to put in a hardwired permanent back up system. Just a thought.

[Stephen1]

Scott, I'll try and get the brushes out this weekend again, been busy as all get out this last week, good weather is finally here and everything wants to get taken care of now.
Nebraska, You are right the I can deduct the cost of a generator against the Airbnb, but the cost is out of my ball park right now, a standby system is in the range of 10K, a new portable generator that can run my place through the Gener Link , 1200$, and I can hook it up to the large torpedo propane tank, makes it an ideal back up system that Cathy can hook up and run if I'm not here.  If I can fix the old one with new brushes ....$50. Geese, I'm cheap in my old age. lol
And of course with the nice weather emergency preparedness slides down the list.

[SwampDonkey]

Any armature shops there? I got free brushes one time for a Makita router at a local armature shop.