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Topic: What Makes a Generator Get Too Hot? (Read 2699 times) previous topic - next topic

What Makes a Generator Get Too Hot?

Just before our last trip, I started the generator. It ran for a while, then stopped with a HIGH TEMP fault. I checked the radiator (it was full) and after a while, tried again. Same result.
 
Now, I think the fan may not be turning. So we went on our 24-day trip, without a working generator. Fortunately, it was March, and we could almost get by without the air conditioner.
 
Now that we are back and the rains have stopped, I started investigating. I took the cover off the end of the motor. The wiring appeared to be in place and intact. The large squirrel cage fan turned and turned and turned, with just a small spin, so it was not the problem.
 
I started the generator. It started right away and ran smoothly. The fan was turning like it should and everything was great. Until it stopped with a HIGH TEMP fault. The radiator never got warm, and neither did the large hose on the bottom (near the door opening). I had expected them both to be very hot, but neither of them even seemed warm.
 
If the coolant is not flowing through the radiator, I would expect it to get hot. Is there a water pump in the generator that makes this happen? Could it be a blockage within the hose itself?
 
What do y'all think should be my next step?
 
Thanks,
 
Trent

Re: What Makes a Generator Get Too Hot?

Reply #1 –
Trent,

What engine do you have on your generator? 

Sounds like you have a remote radiator that has a 120 VAC fan that cools the radiator.

With a remote radiator it could be air in the system that needs to be bled out.

If you have the Isuzu 3LD1 you may have broken the belt that drives the water pump that circulates the water through the system.

Pamela & Mike

Re: What Makes a Generator Get Too Hot?

Reply #2 –
Did you check to see if the fan belt was attached. Mine broke last summer and I didn't see it right away.

Re: What Makes a Generator Get Too Hot?

Reply #3 –
I had a High Egt trigger in my 2005 U320 with a 10kw Powertech generator.  Radiator wasn't hot and neither was the generator.  I checked everything with an IR temp sensor.  I reset the generator and everything worked.  Later the High Temp tripped again.  Again the generator wasn't hot.  Since it was obviously an electrical issue, I checked all the battery connections and found on of the battery connections loose.  It happens that this connector tied all three battery grounds together.  I tightened the connection and the problem never came back.

Re: What Makes a Generator Get Too Hot?

Reply #4 –
Quote
Just before our last trip, I started the generator. It ran for a while, then stopped with a HIGH TEMP fault. I checked the radiator (it was full) and after a while, tried again. Same result.

Not sure what generator you have, but I had similar symptoms on my PT 10 with the isuzu 3LD1.  I verified that it was not overheating with an IR thermometer and replaced the overheat temperature sensor. Problem solved.

Re: What Makes a Generator Get Too Hot?

Reply #5 –
Quote from: Pamela & Mike –
If you have the Isuzu 3LD1 you may have broken the belt that drives the water pump that circulates the water through the system.

Mike, et. al.:
 
I do have the Powertech 10 Kw with three cylinder Isuzu engine, with remote radiator.
 
The radiator and hose did not get hot, but the generator got pretty warm, and the overflow hose from the radiator cap did get hot.
 
Where is the fan belt? I don't remember noticing it when I checked the oil level. My recollection is that I inherited a couple of fan belts for the generator from the PO. Is there more than one fan belt?
 
Will check for that tomorrow. Sounds like a straight forward fix if I can figure out how it is routed and what I have to loosen to put a new one on. Anyone got a picture showing its location?
 
Thanks,
 
Trent




Re: What Makes a Generator Get Too Hot?

Reply #7 –
Trent,
If the remote fan isn't running, its breaker may be tripped or has failed.  I'd confirm its operation before proceeding further.

Re: What Makes a Generator Get Too Hot?

Reply #8 –
The belt is behind a shroud on the drivers side of the engine. If I recall correctly there is no idler to loosen/tension the belt, you have to get the correct size and work it over the pulleys.

So far i have had generator overheating faults due to the remote radiator fan not running - twice (faulty circuit breaker, broken wire), vibration dampner (insulation fell off the inside of belt shroud), and failed over temperature sensor. Check Barry Beam's website for lots of info.

Re: What Makes a Generator Get Too Hot?

Reply #9 –
Quote from: TulsaTrent –
Where is the fan belt?  Anyone got a picture showing its location?
 Is there more than one fan belt?

Trent,

The pic that craneman posted shows the belt. (you have just 1 water pump belt) You just have to roll the generator out so you can get to the belt guard. The most important tool for this job is a 5 gal bucket to set on.  The shield has either 3 or 4 bolts that hold the shield in place. (newer engines have 4 bolts)  The shield is just below the radiator cap or said another way while you are setting looking at the generator it will be on the far right side of the engine opposite the generator end.  Yes it is a little difficult to get the shield off but once you have done it a couple of times the job becomes simple.

Here is a link to the complete thread that craneman  was referring. Crankshaft Pulley on Powertech 10KW w/Isuzu 3LD1

Pamela & Mike

Re: What Makes a Generator Get Too Hot?

Reply #10 –
There are two safety systems incorporated into our generators.  One is a low oil pressure sensor and the other is an over temp sensor.
Both of these sensors will shut down the generator if parameters are met.  It may be possible that the high temp safer sensor is malfuncting.  This sensor is in the back of the engine and in order to get at it you must slide the gen out and also remove the bottom cover.

Hope it goes well
Jason

Re: What Makes a Generator Get Too Hot?

Reply #11 –
Quote
If I recall correctly there is no idler to loosen/tension the belt, you have to get the correct size and work it over the pulleys.

Obviously I didn't remember correctly  ::) . There is an adjustment on the idler pulley.

Re: What Makes a Generator Get Too Hot?

Reply #13 –
Quote from: Pamela & Mike –
They put either an idler pulley or alternator in that hole

Mine only has two pulleys and the belt *IS* there. It does not look glazed, so I assume it is turning the water pump pulley.
 
Woe is me, woe is me.
 
Anyone know how to try to bleed air out of the system radiator system? Wait! I just realized it has a petcock at the top of the radiator itself (as if they installed it upside down). Could I open that to try to let air escape? No, that doesn't make sense.
 
Do I have to roll the generator back in to run it?
 
the insulation liner for the Quiet Box is totally trashed. Worse than that, the piece for the back wall was crumpled up along the driver side of the box. There are other pieces of it laying all over, with some accumulated oil making a genuine muck mess. I think I might be able to take the Quiet Box apart without totally removing the generator. It deserves a GOOD cleaning and then some real insulation to turn my Noisy Box back into a Quiet Box.
 
It's a shame, because everything looked so nice just opening the door at the front.  :o  :o
 
Still need some more advice. The idea of a simple fix is over. The generator still looks good and runs good for a while. Because of that, it doesn't sound like a heat sensor, because it would probably not let it run at all. The significant symptom is still that the radiator does not appear to be getting the coolant flow necessary to cool the generator.
 
Thanks,
 
Trent

Re: What Makes a Generator Get Too Hot?

Reply #14 –
I would check at the breakers when you get to turn it back on if you are getting power there. I had an over heat light come on and it was the end unit that burned out and was not sending 120 to the fan so it would run the engine but not cool it and it would shut off.

Re: What Makes a Generator Get Too Hot?

Reply #15 –
Quote from: TulsaTrent –

Mine only has two pulleys and the belt *IS* there. It does not look glazed, so I assume it is turning the water pump pulley.
 
Woe is me, woe is me.
 
Anyone know how to try to bleed air out of the system radiator system? Wait! I just realized it has a petcock at the top of the radiator itself (as if they installed it upside down). Could I open that to try to let air escape? No, that doesn't make sense.
 
Do I have to roll the generator back in to run it?
 It won't be an air bleed problem. Can you start it and look at the belt and see if it is turning? The dampener could be bad and not turning the outside of the pulley. Don't know if there is a thermostat that could be stuck closed, but if it has one check that by removing it and putting it hot water.
the insulation liner for the Quiet Box is totally trashed. Worse than that, the piece for the back wall was crumpled up along the driver side of the box. There are other pieces of it laying all over, with some accumulated oil making a genuine muck mess. I think I might be able to take the Quiet Box apart without totally removing the generator. It deserves a GOOD cleaning and then some real insulation to turn my Noisy Box back into a Quiet Box.
 
It's a shame, because everything looked so nice just opening the door at the front.  :o  :o
 
Still need some more advice. The idea of a simple fix is over. The generator still looks good and runs good for a while. Because of that, it doesn't sound like a heat sensor, because it would probably not let it run at all. The significant symptom is still that the radiator does not appear to be getting the coolant flow necessary to cool the generator.
 
Thanks,
 
Trent
Can you start the generator and see if the belt turns? The damper could be bad and not turning the outside of the pulley. If that is good then pull the thermostat and put in hot water and make sure it opens. Can't think of any other thing that would stop flow

Re: What Makes a Generator Get Too Hot?

Reply #16 –
Quote
The generator still looks good and runs good for a while. Because of that, it doesn't sound like a heat sensor, because it would probably not let it run at all

Don't rule out the over temperature sensor just yet. My generator would run approximately 15-20 minutes from a cold start before the sensor shut down the generator on a false overheat alarm. It would shut down much sooner from a warm start.

bob

Re: What Makes a Generator Get Too Hot?

Reply #17 –
Quote from: Bob McGee –
Don't rule out the over temperature sensor just yet. My generator would run approximately 15-20 minutes from a cold start before the sensor shut down the generator on a false overheat alarm. It would shut down much sooner from a warm start.

bob
Wouldn't the radiator and lower hose be warm, which his is not?

Re: What Makes a Generator Get Too Hot?

Reply #18 –
Quote from: TulsaTrent –

Mine only has two pulleys and the belt *IS* there. It does not look glazed, so I assume it is turning the water pump pulley
 Wait! I just realized it has a petcock at the top of the radiator itself (as if they installed it upside down). Could I open that to try to let air escape?

Trent,

If you don't have an idler pulley I don't see how you have enough tension on the belt to turn the water pump.  Someone may have tried to remove the idler and put a shorter belt on to get by rather than replace the bearing in the idler that went bad.

That is one of the petcocks as the other should be on top of the engine. Someone could have taken the one off the engine out and replace it with a pipe plug so look for both. If the one on top of the engine has air trapped behind it then there isn't anything but air on the thermostat and that thermostat won't work reading air temp.

Pamela & Mike

Re: What Makes a Generator Get Too Hot?

Reply #19 –
I got the front and right side off of my QB, and got some pictures. There is definitely not an idler, nor any place to mount one on the engine. The picture that Craneman uploaded showing the gorgeous green stripe belt, with the large idler looked very heavy duty. The first picture shows what mine looks like. It reminds me a little bit of a sewing machine belt.

The second picture shows the very long hose that runs from the top of the water pump to the back of the QB to go to (or from) the remote radiator. I do not understand why this hose is so long. Could that be part of my problem? Why doesn't it just go straight over to the fitting? The longer hoses that are required to move the generator forward are outside of the QB.

This picture also shows the back wall of the QB, without any insulation. It does show the remnant of the insulation having been there, but it has been removed. That particular piece of insulation was wadded up at the bottom of the QB, under the belt pulley. I pulled it out and took a picture. It is shown in the third picture. It looks like it was some kind of fabric about 1/8" thick. Attached to that was some kind of foam material, about 1/2" thick. That foam material had totally disintegrated and was laying on top of the horizontal surfaces. I vacuumed some of it off of some of the engine surfaces, but it will take a wire brush to get it cleaned off.

The fourth picture shows the bottom of the driver's side of the QB, where the insulation had been discarded. There is still a lot of crud and oil residue there that needs to be cleaned out. Another thing that can be seen is the edge of the oil pan gasket, which is still a bright orange color, without any sign of grease visible on parts of it. The generator had a major service done in 2013 (a year before I bought it) but I do not know what all in entailed. I had the oil and all filters replaced last fall. Nobody seems to have done anything about replacing (or even removing) the old insulation. I hope to do that soon.

The fifth picture shows the underside of the generator QB. Several things are visible in this picture. There is a large rectangular hole (guessing about 3" x 10"), and another hole further on; neither have any kind of screen or covering. It also shows the very heavy pipe that comes from the generator to the flexible exhaust hose. One problem is that pipe also stops the generator from coming all the way forward (maybe by design?). The right side of the picture shows the flat bar that forms the front bottom framework on which the QB slides. It has two nuts that, if removed, would like let the QB slide further forward. It does not seem to be wise to remove those two nuts while the generator is very far forward as it would substantially weaken the base frame assembly. I assume that if you wanted to remove the generator, one of the steps would be removing that large exhaust down pipe, which would allow it to slide further forward. (Obviously you would also disconnect other hoses and connections, too.)

To recap: I started this journey of discovery, because my generator started throwing High Temp faults after running a while. (After never having this problem for the last year and a half.) I had hoped that the fan belt was the problem (it might still be, depending on whether it will really turn that water pump properly). I have gotten this far and discovered that I still have a lot of generator clean up to do, but am no closer to eliminating my High Temp problem. From the responses I received originally, the heat sensor is still a suspect, as is air in the system, or bad water pump.
 
Can I run the generator without replacing the two locking bolts, or should I put them back in place? Do any of you who are taking this journey with me have any suggestion about what steps I should take from here? I would appreciate any help any of you can offer.
 
Thanks,
 
Trent