003A developed sudden starting circuit short 24v to ground

[Chainbreaker]

I agree that "earth grounding" is not the cause of his 24V DC shorting situation. Since he mentioned his grounding connects to a driven ground rod it's just good practice to verify his configuration, for safety's sake, to understand that his unit is "properly" grounded when working on it.

Is he double grounded? The subject of double grounding is highly debatable...the "Sticky: MEP-003A Hook up question" will leave your head spinning when reading the various opinions. Some within the Electrician Trade on here say "NO double grounding", others say its "OK if done properly". But that's a whole other subject that won't fix his present starter/24V short dilemma.

Sounds like he has ruled out any +24V wiring harness shorts to chassis. That would then seem to point back to a Starter internal short.

 

[glcaines]

I don't understand how it could possibly be the slave receptacle causing his problem. He said earlier that it only shorts out when he energizes the starter. The cables to the slave receiptacle are connected directly to the battery via the battery cables. If the slave receptacle or slave receptacle cables were at fault, he would have a direct short to ground as soon as he closed the knife switch. It sounds to me like a faulty starter or solenoid.

As far as double grounding goes, I was told by my local EMC that when I hooked up my 003A to my transfer switch that i should never have a double ground, because it could cause a ground-loop. I was told to tie the genset ground directly to the house ground. They told me to only use the ground rod when using the genset for a remote power source. Mine is trailer-mounted and gets used as a remote power source occasionally. I was told that they would fail my inspection if I double grounded.

 

[Chainbreaker]

....The cables to the slave receiptacle are connected directly to the battery via the battery cables. If the slave receptacle or slave receptacle cables were at fault, he would have a direct short to ground as soon as he closed the knife switch.

Not in all cases do the slave cables run to the battery. Actually on my unit the + slave cable goes to the Solenoid + terminal and the - slave to - starter post. If there is a rubbed spot in wiring against the floor of his trailer in + wire it could be experiencing an intermittent contact issue. The reason I was concerned is because that is what happened to mine, it had a rubbed spot against trailer floor through outer cloth. Fortunately I caught it before it had rubbed all the way through the remaining internal insulation. He said the ground wire is getting hot, and he saw sparks at or near the bare grounding wire on trailer floor when he attempted to start. (why is it sparking in that area???). Not sure how long that happens after he closes knife switch and hits start? Just theorizing it could be a an "intermittent high current draw type of short". But he checked and said no chafing of that wiring, so back to starter as the culprit.

....As far as double grounding goes, I was told by my local EMC that when I hooked up my 003A to my transfer switch that i should never have a double ground, because it could cause a ground-loop. I was told to tie the genset ground directly to the house ground. They told me to only use the ground rod when using the genset for a remote power source. Mine is trailer-mounted and gets used as a remote power source occasionally. I was told that they would fail my inspection if I double grounded.

Same here! I made sure my trailer mounted unit has the L0 bond wire (J10) detached from generator frame stud gnd point and 4 wire to inlet box with gnd connection through inlet connector only. I always keep unit plugged in to house inlet box. If not, then its back to a SDS configuration with driven gnd rod (not both).

 

[reybo]

He bought it for household emergency backup a year or two ago to power emergency medical devices, etc, Which I think he has connected to a transfer switch via a plug in receptacle.
Ike

Thought about a plug-in and decided to go with fixed wiring instead. It was done by a licensee. My input was A) Don't waste my money, and B) Don't put anything here you wouldn't use yourself. I was surprised how fast the job went. You can tell he was a local licensee: he didn't label any of the switches. Seems to be an unwritten law around here.

 

[reybo]

Finally this morning at 8 I had the chance to spend some quality time with my 003A. Hold its hand, ask why its shorting its starter, find where its seeping diesel, see how to fix these. If you were lucky enough to go through life in tune with machinery, what transpired will not surprise you. It explains why you do your own repairs.


The fuel seepage ended, I hope, by tightening the pet cock and the drain cap, both of which had vibrated just a bit loose over the decades.


I ran fingers over all wires capable of a serious battery short and nothing odd was found. Tight connections, full insulation. It's not a wire problem.


So I tried to start it and nothing was wrong. Starter spun, engine ran. No problem. A routine 24 min. exercise.


If the starting short returns, then is the time to pull the solenoid and maybe the starter. But not now, not while it's OK.


Took some photos. This installation has two precepts: 1. Power outages have an aversion to warm, sunny days. 2. Military generators should last a long time.


The trailer is on the lee side of the garage at the opposite end of the house from the bedrooms. The exhaust faces the street which is 100' away. The marine plywood roof is bolted in place with stainless fastenings. The operator area cover is marine plywood and folds down on stainless hinges. The tarp is waterproof camo. The fuel line draws from a thousand gallon underground heating oil tank. It took 3 months to assemble the right fittings for that fuel line, and part is custom-made. The tires are parked on wood. The red knife switch disconnects the batteries from the system. The barely seen black knife switch isolates one battery from the other for checking state-of-charge with a normal 12v load tester. It also allows use of common 12v solar chargers if my uncommon 24v solar fails.

Click on these to enlarge.

 

[Chainbreaker]

Nice setup, I'm particularly envious of your 1,000 gal aux tank!

In the 2nd photo what is the green gnd wire, that appears to be going into the AC Load Terminal connection area, attached to???

 

[reybo]

Nice setup, I'm particularly envious of your 1,000 gal aux tank!

In the 2nd photo what is the green gnd wire, that appears to be going into the AC Load Terminal connection area, attached to???

Ground.

 

[reybo]

Nice setup, I'm particularly envious of your 1,000 gal aux tank!

Still a work in progress. Over the winter, the fuel line fed through the underground tank's filler pipe. Stuffed with a towel and under a tin can ranks as inelegant. The plan for permanent replacement was to drop the gen fuel line through the underground tank's breather pipe.

Today was install day for that, but I was shot down as soon as I measured the drop. It was 18". Huh? Google showed me about 50 tank diagrams and without exception, the breathers on all of them change direction twice on the way down, using two right angle bends. My plan is kaput.

I'm between ideas at this point. It was discovered in the fall that the return line, which my furnace no longer uses, reaches only a few inches into the tank. In theory that can be changed, but digging up and futzing with a 62-year-old tank installation brings risk.

So probably we're stuck with using the filler pipe. I'll ask my wife to choose a less unattractive towel, and cover the mess with a floral trash can. There's enough shrubbery to conceal the line.

 

[Chainbreaker]

Stuffed with a towel and under a tin can ranks as inelegant.

Not if you spray that tin can with some camo paint and use an olive drab towel!

Now you do know that Murphy's law says your starter is just waiting for a real honest to good power failure to rear its ugly head again. It just acted up during one of your test runs just to let you know what mayhem it was capable of. You might consider becoming a spare parts hoarder in the meantime. You could start with a solenoid and starter. That way you know you got it covered when the problem chooses to return.

 

[reybo]

Not if you spray that tin can with some camo paint and use an olive drab towel!

Now you do know that Murphy's law says your starter is just waiting for a real honest to good power failure to rear its ugly head again. It just acted up during one of your test runs just to let you know what mayhem it was capable of. You might consider becoming a spare parts hoarder in the meantime. You could start with a solenoid and starter. That way you know you got it covered when the problem chooses to return.

That's a wise course. For sure I'll try to pick up a solenoid. This one is 24 years old. It's been longer than that since I worked on a solenoid or a starter. Memory says solenoids get pitted and need replacing, while starters get rebuilt. Seems to me I have a couple of rare starters on a shelf, one for a Mazda RX-7 and one for an Isuzu Trooper. Might be able to do some trading.

Is it possible to find a parts list for a 1990 gen?

 

[Chainbreaker]

Is it possible to find a parts list for a 1990 gen?

Try here: http://www.steelsoldiers.com/upload/Generators/TM5-6115-585-24P.pdf

Pg 120 of PDF (pg #104 of printed manual) begins starter section

 

[Isaac-1]

You can get a cheap piece of junk compatible Chinese import starter that will work on your MEP-003a for about $125.


Ike

p.s. changing these can be a pain, it is a tight space to get to the bolts, a wobble extension set really helps, also a dogleg offset box wrench

 

[dependable]

View attachment 496303View attachment 496305

Have not seen that Onan tag before, and on a Libby too. DJFM, I guess the official Onan desigantion.

 

[reybo]

Have not seen that Onan tag before, and on a Libby too. DJFM, I guess the official Onan desigantion.

I'll have a more readable copy of that tag in a few days.

 

[reybo]

You can get a cheap piece of junk compatible Chinese import starter that will work on your MEP-003a for about $125.


Ike

p.s. changing these can be a pain, it is a tight space to get to the bolts, a wobble extension set really helps, also a dogleg offset box wrench

The manual makes everything sound benign. "Step Two: After kissing your elbow, insert the square peg in the round hole ... "

Seems every starter is an exercise in awkwardness. On the plus side, this one won't drop grunge on your face.

 

[reybo]

Try here: http://www.steelsoldiers.com/upload/Generators/TM5-6115-585-24P.pdf

Pg 120 of PDF (pg #104 of printed manual) begins starter section

Odd. That PDF said pages 119/120 blank. I'll search it.

 

[reybo]

Found this, and there are others
Starter/solenoid combo for $221 http://tinyurl.com/ln8ywwt


Listing says:
MEP002A-MEP003A New Starter
$221.00
New aftermarket 24 volt Starter for MEP002A and MEP003A units. This is the “Type II” starter, which is a more efficient starter introduced around 1990 requiring less battery power as it is geared more aggressively.
Features:
100% Brand New Aftermarket Unit
NOT Remanufactured
Meets or Exceeds OEM Specs for Fit and Performance
24 volt
10 teeth
CW rotation
Weight: 13 lbs

Also, someone on eBay twice offered a 2920-01-048-8661 Solenoid for $21. He had no takers, perhaps because the only comments regarding working condition were NEW and NON-RETURNABLE.

Does anyone use Diesel Kleen Plus Cetane Boost? Although sold at Walmart for $17/gallon, it gets good press anyway.

 

[gimpyrobb]

I have both starters and can't say one is heads and tails above the other.

 

[tbearatkin]

Still a work in progress. Over the winter, the fuel line fed through the underground tank's filler pipe. Stuffed with a towel and under a tin can ranks as inelegant. The plan for permanent replacement was to drop the gen fuel line through the underground tank's breather pipe.

Today was install day for that, but I was shot down as soon as I measured the drop. It was 18". Huh? Google showed me about 50 tank diagrams and without exception, the breathers on all of them change direction twice on the way down, using two right angle bends. My plan is kaput.

I'm between ideas at this point. It was discovered in the fall that the return line, which my furnace no longer uses, reaches only a few inches into the tank. In theory that can be changed, but digging up and futzing with a 62-year-old tank installation brings risk.

So probably we're stuck with using the filler pipe. I'll ask my wife to choose a less unattractive towel, and cover the mess with a floral trash can. There's enough shrubbery to conceal the line.

The fuel fill caps on our furnace growing up was just a fitting that screwed onto the top of the fill pipe. How about getting some black iron reducers and make that big hole a little smaller? Then once it gets down to the diameter of your fuel line maybe use some diesel compatible sealer around the top. You will still have to remove it to fill it up or you could tee it off and be good to go. Does this drawing explain it

 

[reybo]

Good idea! It might be more elegant to use a Y type T. By chance I have two proper size caps, one of them a 1952 bronze job having a channel cut across it rather than a square head. Easier to drill through the channel than through a thick square head. We could have a right angle or through pressure fitting for the oil line brazed into place at the welding shop.