mep 003a

[love-horsepower]

i have a mep 003a that has 81 hours on it now it had 54 hours on it when i got it i used it yesterday and it worked fine but to day when using the 110v outlet to to use a saw and it is majorly loading the gen set to 75% capacity and the hertz goes down to 55 then when i use my arc welder it will kill the motor and now when i start it up it is under load as it starts and gets up to speed slowly even when nothing is is hooked up to the generator. can any one give me some advise where to look. the volts show good and the hertz when it is running no load. e-mail rodbrace@netzero.net or call 515-202-8090

 

[uscgmatt]

Please use proper punctuation when posting, I had to read it a couple times to figure it out (I think). The resident experts will chime in shortly. Oh and welcome to Steel Soldiers.

 

[aspann]

Welcome to SS Horsepower. Like uscgmatt said, someone on here will solve your problem.

 

[derf]

My MEP-701A registers a load on the meter when you use the convenience outlet if you have the switch in the right place.

What kind of saw are you using? A 3HP table saw might load it up some.

 

[love-horsepower]

i have a Milwaukee 8 1/4 metal circular saw 8 amps i have used it on the convienence outlet many times as well as my miller dynasty 200 stick tig as this is my second trailer that i have built with this genset and welder . it doesnt show a load but is very slow at coming up to speed like it is under load which i think it is the guages allread 208v 65 hz 0% load but if i strike an arc within 15 seconds it starts to pull down and one time i kept welding it killed the engine. any ideas?

 

[Speddmon]

I can't explain why the saw would show you as having 75% load because it shouldn't, but the bogging down with the light load on it, and slow coming up to speed, combined with the fact that you seem to be running good when it is unloaded leans toward an engine problem from the sound of it.

 

[derf]

Engine or regulator. Can't a bad regulator or shorted diode bog down an engine?
The 003 should hardly blink at 8 Amps.
Maybe switch it to three phase and with no load check voltages of all three phases?

 

[love-horsepower]

ohms ok . voltages on all legs between are 219 221 221 checked fuel screens on the bottom of pumps and checked flow out of the bottom of the last fuel filter w/ pumps on plenty of flow there but not conclusive as to out put through filter . i forgot to check each to ground for short. i will go check that now. i checked and i have continuity between ground and terminals l1,l2,l3 in the 3 phase 208 mode does this mean that it has shorted out or am i missing something?

 

[PeterD]

If you have a clamp-on ammeter, that may help you greatly in seeing if there is an 'external' load on the generator head. Check each of the leads coming out of the head to the control panel. This won't help if the head itself is shorted, but will help if there is a problem elsewhere. OK, this is a remote shot, but worth a few minutes if you can do it.

You would not be the first person to have a tool fail, and draw too much current...

 

[Speddmon]

If you are running it in 208 volts 3 phase mode, your voltages are way too high. You need to adjust them back down to closer to where they are supposed to be. Continuity to ground doesn't really mean anything in 3 phase configuration. All the coils are connected to L0 in that configuration. Continuity just means you have a complete path to the L0 (ground). You need a specific Ohm reading. 0 Ohms would definitly be a shorted head, but the reading should be at least a couple of Ohms. It could be as low as 1 or 2 ohms, I'll check one of mine tonight and see if I can give you a general idea of that if should be.

 

[love-horsepower]

ok i will check w/ a different meter my meter displayed zero ohms, but i will recheck. thanks rod

 

[love-horsepower]

all three legs between are .3 ohms. what else could it be? im stumped.

 

[Ken_86gt]

I would think that you should measure almost 0 ohms between any leg and L0 if connected in a Wye configuration. Maybe you could figure out a way to do a load bank run with it.

 

[Speddmon]

I would think that you should measure almost 0 ohms between any leg and L0 if connected in a Wye configuration. Maybe you could figure out a way to do a load bank run with it.

0 ohms from any leg to L0 in any configuration is a short and not a good thing.

Rod,

I double checked your readings against my known good generator and I have the same 0.2 to 0.3 ohms to L0 from any line leg. And between any 2 lines I get 0.3 to 0.4 ohms.

Like we discussed on the phone, start looking at the engine. Check the fuel pumps, fuel lines, filters, screens, and even the IP if it comes down to that. I doubt it's the generator head.

 

[love-horsepower]

I dont think it is the motor it could be filters maybe. I checked the wiring the best I could looked into the bottom of the gen head through the airvents the wiring, looks great, windings perfect.i checked the pump screens and they looked good. Ran the pumps, then under pressure drained them and all have good flow out of thr drains? I will dig more this weekend any other suggestions?

 

[Ken_86gt]

Spedmon- like I said- it should measure almost 0, just as you confirmed. The winding is nothing more than a coil of wire and is a direct short until you induce the current to flow.

 

[Speddmon]

Spedmon- like I said- it should measure almost 0, just as you confirmed. The winding is nothing more than a coil of wire and is a direct short until you induce the current to flow.

Yeah, I just re-read your post....I didn't see the "almost" 0 ohms until just now.

 

[love-horsepower]

i found the problem, it was the shut down solenoid it is a brass screw w/ a lock nut and it was loose and worked down, so when it needed more fuel for load the Governor couldnt add more fuel as it it the bolt. thanks guys! also put on seddmons billet oil fiter adapter what a great piece!

 

[G Carttar]

I have an MEP-003 and the regulator died. A friend of mine who knows his stuff replaced it with an aftermarket unit and I have no problems.
However in looking over the specs while we were doing that, I found mention (it's been awhile and it's not at my fingertips) that these generators have an unusual neutral vs. ground situation.

You should not bond the L0 (neutral) to generator chassis in some output switch configurations. When using the convenience outlet, and if you are powering something with a neutral/ground bond, you may experience loading on the generator because of it.

IIRC from the manual, in some switch configurations, the neutral L0 lug FLOATS and is NOT ground.

In a residential environment, the only ground/neutral bond should be at the utility company's service. When running your house on the genny, you might run into trouble if you have a generator chassis ground-to-neutral bond in your electrical panel, especially if you back feed your house through a dryer outlet. DON'T do that.

Run the chassis ground to your house for sure, and ground the genny with a ground stake AT the genny, but avoid a neutral-to-ground bond until you are sure there is no ill-effect by doing it. Disconnect or isolate the utility company neutral from your system when running on the genny.

Use a proper transfer switch.

Mine is 3-phase 208/120, single phase 240/120, or single phase 120 only switchable by selecting the configuration with a rotary switch next to the master breaker.

I always set it for the appropriate configuration depending on the load.
It is 30A 3-phase, 50A single phase, 30A 120V only.

The Military did some funny things with ground bonds sometimes.

If you are experiencing loading on your genny (slow labored start) try starting it with generator main turned OFF and the load disconnected, if no loading then connect your load with the breaker off, if no loading then turn on the genny main. If it loads when you turn on the main with nothing pulling juice, you might have a L0-ground problem.

Other opinions/findings are solicited.

Greg Carttar

 

[steelypip]

Hm. As I read my copy of the 2008 NEC (sec. 250.35), it looks to me like the generator should not be separately grounded, but instead should be grounded to the service ground of the house. This would be to avoid a ground loop through a grounding conductor between the generator set ground and the service ground on the house.

Note that this is not in the operator manual for the genset because the military assumes the generator will be the service, so it gets the ground.

Agree completely, though, about the weirdness of how open ground/ground fault/other odd stuff can happen with the mil spec gen heads so that they could offer multiple voltages and 1 phase 1 leg/1 phase 2 leg/3 phase from the same gen head by rearranging output lead connections. The operator TM (5-6115-584-12 for my MEP-002A) is generally pretty clear on this.

OPERATING IN ALTERNATE MODES.
WARNING
When selecting position 120V, 1 PH unit is
in 2 wire conf iguration. A situation
can/may exist in allowing a double fault to
occur. To eliminate this possibility the
reconnection switch will be rewired by using
an AWG #4 wire jumper between terminals
#LO and #6 of section g.

There's also a warning on the genset itself about possible ground fault conditions in 120/1ph mode as well.

Do it to code - it's not that hard or expensive. the NEC has provisions for a manual backup generator and manual load management, which is the cheap solution. As my house didn't have a service disconnect other than the main breaker, I went with an inline manual transfer switch that now doubles as a service disconnect between the meter and main panel and also satisfies the transfer switch requirement of the NEC. Put a weatherproof male plug on the generator side of the transfer switch and a matching socket on your four-lead running from the genset and your're done.

You can do it even cheaper with a panel interlock kit and a clamp for the backfeed breaker. It works, it's reasonably safe, and it meets code.

Powering the house through the dryer outlet? No, that's not safe, and it positively doesn't meet code. Bad outcomes with both the law and insurance if anything bad happens. Of course, if you electrocuted yourself with the dryer plug, you probably don't care anymore...