MEP-002A Question

[Tweeter166]

OK i just bought a few MEP-002A's and have been told 2 diffrent answers to 1 question

I read dont idle the engine but what does this mean?

i was told dont idle the engine cause you are only running just 1 light bulb in your tent cause you will burn it up..

i was told even with it running at the goverened 1800 rpm its made to run dont use it to power just 1 light bulb in your tent or it will burn it up..

What is the truth to this? i would figuar with it running at the 1800rpm and the machine set you right with the dials and stuff it can set there and run all day long with no load or very little load all the way up to its rated output.. is this not true?

 

[skidunits4you]

Well you need to run it at 1800 rpm to get 60 cycles and running it with little or no load will cause wet slacking and can damage the engine. Diesel generators should be run under load as much as possible. this way the run hot enough to burn all the fuel and not build up sludge in the cyclinders. If you only need one light buld you need a smaller generator.

 

[doghead]

There are much better generators available, if you only want to run a single light bulb.

Care to tell us who told you these things?

You should consider downloading and reading the Technical manuals, for proper operation of the generator.

 

[Tweeter166]

Not looking at the engine side of this just the generator side of the unit whats the truth?

i dont planing on letting it set and run all day if not being used but say if i got it hooked to my house during a power outage or my cabin in the woods and need power is it ok to run it at the 1800 rpm for 2 100 watt lights? or say with it at 1800 rpm and during the winter during power outage to set and run all night to run my furnace where it would jump from no load to half load as my thermostat calls for heat? again is it ok on the generator side of it not the engine side of it..

 

[Tweeter166]

There are much better generators available, if you only want to run a single light bulb.

Care to tell us who told you these things?

You should consider downloading and reading the Technical manuals, for proper operation of the generator.

1 light bulb is a sample.. say i am building a fence and cut 3 boards then go nail them up and come back 5 min later and cut 3 more boards. or building a cabin in the woods were i would be running a saw evey few min to cut lumber and go nail it up and come back and cut some more boards.. Like you can with a cilvilin gen set..

I was reading a thread earlyer that said dont EVER idle a military gen engine. and i read that in the TM's also but it didnt explain it.. i was on phone a few ago and asked the army guy on other line and he said he heard 1 of the answers i posted.. then i was talking to another guy and he answered with the other answer i posted above so i am asking whats the truth?

 

[doghead]

It will function fine for what you described, but do not idle it or the voltage regulator will be damaged.

 

[Tweeter166]

It will function fine for what you described, but do not idle it or the voltage regulator will be damaged.

OK so its the same as any old normal generator.. i just dont want the machine setting there running at a idle rpm correct?.. if its running make sure it running the 1800 rpm or shut it off?

 

[AceHigh]

Not entirely correct. Adjust the speed till the generator is running 60 cycles per second, leave it there. If it gets higher or lower than 60 cps re-adjust it.

 

[Tweeter166]

ok so if i am useing say a hand saw adjust the rpm to maintan a 60 cps on the meter.. if i use more power adjust the rpm to keep 60cps?

So it not really letting it idle as mush as dont let what ever power i am pulling off it let it lug the motor down under the 1800 rpm or the 60 cps?

do i got the idea yet?

 

[DieselBob]

That's pretty much correct. If your governor is working correctly once you set it to 60 Hz it should maintain that as load increases and decreases.

 

[Isaac-1]

Ok, let me try to clear up a couple of things:

It is fine to run this generator to power a saw or other power tools that you plan to run every few minutes, or even a few light bulbs, the problem with wet stacking comes in when you do this hour after hour, day after day. In general to avoid wet stacking (slobbering) you want to ran a diesel engine at over 50% load, of course the military uses conservative specs and oversizes engines on these generators, so that 50% rule of thumb becomes more like 75%. So if you find yourself in a position of running it at lighter loads, you need to make a point of loading it down to 90%+ for half an hour or so out of every 10-20 hours to burn off all the build up.


As to the issue of running at 1800 rpms, a little understanding of how these generators work helps, these units have an Electronic Automatic Voltage Regulator, which boosts the residual voltage from the exciter windings to generate power, when at lower than running engine speeds the AVR will try to go into full boost to keep the voltage up, thus burning out the voltage regulator. Many cheap generator have much more primitive voltage regulations systems (or no voltage regulation at all), which as it turns out are far more robust than the AVR's used in these MEP generators, the trade off is poor regulation, like voltage sags while having high amp loads, like trying to start an electric motor, etc. So again NEVER run these generators at idle, of course for some reason known to no one these generators are equipped with an adjustable throttle, which should only be used to fine tune the governed speed to maintain 60 hz (+/- 2 hz is fine for most electric loads, so it can be a set once and forget, just like most civilian models whose adjustment is only done by service technicians).

Ike

 

[Speddmon]

Ike pretty much summed it up. I will just clarify what he and others have said. Set the throttle at 1800 RPM's (60 Hz) or maybe just about 2 to 3 Hz more. That way if you go from no load to full load when a large appliance turns on, your frequency will not dip below 60. Even if it does, it will only be maybe 1 to 2 Hz. When adjusting the throttle, try to use a Kill-a-watt meter or a good multimeter with a frequency setting as the frequency gauges on these generators are notoriously unreliable. Also, get it to the proper speed right away, and then wait about 10 minutes until it is warmed up and then do the final adjustment. It will settle in after everything is warm and the frequency will be slightly different than what it was with the engine cold.

Once the throttle is set....leave it alone! Just shut the generator off, and then when you start it again, it will go right to the proper speed. About the only thing you'll need to do after that is just check and verify the speed every now and again.

 

[NJ_Toolnut]

Wet Stacking

I think I read a post herein that stated MEP002a and MEP003a generators are not very susceptible to wet stacking because they are air cooled. I have never experienced wet stacking with my MEP003a, but this could be because I have never run it without at least 20% load for more than ten minutes or so. Has anyone experienced wet stacking with these units, and if so, what was the load and duration of operation?

 

[Speddmon]

NJ,

Wetstacking can occur with ANY diesel engine. However, you are correct that it is less likely with the air cooled engines. It's just the nature of the beast, an air cooled engine naturally runs a little hotter that a liquid cooled one. I have never experienced wetstacking on an 002 or 003, but I would imagine if it were to happen it would be during winter months when the engine is going to be running at it's coolest

 

[Isaac-1]

I have heard of it happening with civilian Onan diesel J series engines when they were installed in applications where they would run many hours at low load, the DJB and DJC units were commonly installed for supplimental power in buses, fire trucks, and other diesel powered vehicles as well as a variety of backup and other industrial uses like light tower trailers.

 

[Tweeter166]

thanks guys for clearing this up..

Got 1 more question.. how important is it to drive a ground rod when useing these units? small loads diff from big loads on useing ground rod?

 

[n1oty]

Grounding is VERY important for safety.

John

 

[LuckyDog]

... how important is it to drive a ground rod when useing these units? ...

Just depends on how much 10 - 12kW of electricity running through your body would bother you.


Bothers me ALOT.

Stay Safe

 

[NJ_Toolnut]

I think the correct answer about whether or not to drive the ground rod depends on how you intend to hook up the generator.

Please read this thread:

http://www.steelsoldiers.com/auxiliary-equipment/40290-mep-003a-hook-up-question-2.html

Note especially speddmon's post (#20)

The search utility is your friend.

Best regards,

Stan

 

[Isaac-1]

There is a message thread going on over on the Smokstak board on this very topic, it seems OSHA has issued new guidelines to NOT drive ground rods for portable generators. Of course if you have it connected to site wiring the NEC code may apply, which opens another whole can of worms over how the grounding / bonding is done.