MEP-802a continues to blow the 3amp fuse

[FdeG]

Hello, I'm new to the forum. Thanks for the warm welcoming notes.
I just purchase an MEP-802a diesel generator. Tested and worked fine.
Moved to the current location and now the 3amp fuses keeps blowing. Not sure what to do.
Any suggestions? attached please find the fuse holder located between the voltatge selector switch and the voltage regulator.
Checked for loose wires etc. all looks good
Thank for your help!!!

 

[DieselAddict]

Does it blow immediately or at random times? Engine running or engine not running?

 

[FdeG]

The fuse blows immediately. it is rated at 3amp. I measured with a recorder 4.8 amps. The engine starts/runs great but that fuse prevent the generator from supplying any power out

 

[zarathustra]

With the fuse removed and the generator running, does the Hz meter read ~60 Hz? I know the voltmeter won't read, but the Hz meter??

Without seeing the unit, but based on your saying that it worked before it was moved, I'd guess that the Hz meter is reading ~60 hz without that fuse in there. The generator was designed to generate a low voltage ~24 VAC without the regulator connected. That would be enough to deflect the Hz meter.

That fuse on the regulator was installed as a field fix to keep the stator from failing in the case of the regulator circuitry going out.

Now, one other thing about that fuse. It needs to be a 3 amp 600 volt, slow blow (or time delay) fuse. If you don't have a fuse in there with those ratings then the fuse itself might be the problem. That fuse was specified in the service bulletin for installation of the fuse as a protective device.

Just as a further question..... your generator starts, but it is a hard start wherin you have to crank the engine for a while before it starts, or does it fire up immediately.

If it is a hard start, take an ohmmeter to the two glow plugs and see if they work. Anytime you have the master switch in the START position, those two glow plugs should be energized.

I bought some of those fuses the other day and they nicked me somewheres around 17 dollars each for 'em.

I would absolutely NOT replace that fuse with a larger amperage fuse.

 

[FdeG]

With the fuse removed and the generator running, does the Hz meter read ~60 Hz? I know the voltmeter won't read, but the Hz meter??

Without seeing the unit, but based on your saying that it worked before it was moved, I'd guess that the Hz meter is reading ~60 hz without that fuse in there. The generator was designed to generate a low voltage ~24 VAC without the regulator connected. That would be enough to deflect the Hz meter.

That fuse on the regulator was installed as a field fix to keep the stator from failing in the case of the regulator circuitry going out.

Now, one other thing about that fuse. It needs to be a 3 amp 600 volt, slow blow (or time delay) fuse. If you don't have a fuse in there with those ratings then the fuse itself might be the problem. That fuse was specified in the service bulletin for installation of the fuse as a protective device.

Just as a further question..... your generator starts, but it is a hard start wherin you have to crank the engine for a while before it starts, or does it fire up immediately.

If it is a hard start, take an ohmmeter to the two glow plugs and see if they work. Anytime you have the master switch in the START position, those two glow plugs should be energized.

I bought some of those fuses the other day and they nicked me somewheres around 17 dollars each for 'em.

I would absolutely NOT replace that fuse with a larger amperage fuse.

Thanks for the info.

the generator starts right the way and easy. does not struggle or hard to start.
Regarding the 60Hz, yes, I can see that gauge measuring around 60 HZ and I did see about 20Volts when I measured it on the 110V outlet on the side of the generator. The fuse I used is in the attached picture.
Now assuming that the fuse i the correct one, and still trips, what do I do??
Thanks for your help

 

[zarathustra]

Since you have the 60Hz signal without the fuse that means that the stator is good.

Replacing a stator is not a task for the faint of heart. One practically has to dismantle the entire front of the generator just to get to the point where he can get to the stator. That is, if he can even find a replacement stator...

So, the fuse has saved the day.

The fuses in your picture are the right rating and physical size, but I can't tell from the picture whether or not it is a time delay fuse. You might want to google that part number to see if it is slow blow/ time delay or not. Since it blows 'immediately' and not in a few seconds it is worth a check.

The first thing I'd do is to make sure I had several (~5-6) of the correct fuses.

Since moving it 'seems' to have caused the problem then the first thing I'd do is to remove the regulator and give it the sniff test. Does it smell like it has cooked? Probably not. Next thing I'd do is to make sure that the ground for the regulator is good. One of the wires is connected to a ground terminal on the inside of the unit. Remove those wires and clean up the connection.

If there is any corrosion on any of the terminals on the regulator clean them up and re-install the regulator and test. It is possible that there was a marginal connection on the regulator / ground, and moving the unit aggravated that connection.

Unlikely, but worth a shot.

If you have a known good generator, or known good regulator, swapping out the regulator would tell you a lot.

There are other areas where movement could cause a problem.

WITH THE BATTERY GROUND DISCONNECTED

You can remove the front cover of the generator stator. Inside there is a small terminal strip which could have developed a marginal connection. Remove the wires to the strip one at a time, clean up the tabs and re- install. That strip is not easy to reach, but there are only a couple of wires to fool with.

In general, if a component didn't fail during the move you are probably looking at a marginal connection. If you use the wiring diagram you can remove plugs from the jacks and plug them back in on any of the circuits that connect to the regulator.

All that said, assuming you have the right fuse, my money is on a bad regulator or a bad connection on that little terminal strip in the front of the stator.....

good luck

z

 

[cuad4u]

First are you sure the fuses in your 802A are the right value? If they are supposed to be 3A it is hard to tell from the picture, but these fuses may not be slow-blow. Most slow-blow fuses of this type have "dual element time delay" or something similar printed on the barrel. Slow blow means the fuse will take a momentary overload without opening, unlike a "regular" fuse that will open quickly on an overload. Yes dual element time delay fuses of this type are quite pricey.

EDIT: Sorry I did not read the previous post in its entirety. Most of what I recommended was covered in that post.

 

[FdeG]

First are you sure the fuses in your 802A are the right value? If they are supposed to be 3A it is hard to tell from the picture, but these fuses may not be slow-blow. Most slow-blow fuses of this type have "dual element time delay" or something similar printed on the barrel. Slow blow means the fuse will take a momentary overload without opening, unlike a "regular" fuse that will open quickly on an overload. Yes dual element time delay fuses of this type are quite pricey.

EDIT: Sorry I did not read the previous post in its entirety. Most of what I recommended was covered in that post.

Thanks again. You are correct. The fuse in the picture is a 3amp but NOT a time delay one.
I will try after work with the correct one. Thanks for your recommendations. Will have a feed back tomorrow morning

 

[OldPhart]

So....is 4 1/2 + years long enough to determine whether or not the fuse was the problem here?

 

[Guyfang]

So....is 4 1/2 + years long enough to determine whether or not the fuse was the problem here?

The fuse can never be the problem. The VR is bad, and that's the only thing that could blow the fuse.

 

[OldPhart]

TYVM for the QUICK response, Guyfang-I was kinda playing around there, resurrecting a long-dead thread just from boredom...