Mep-002a Ammeter-Voltmeter transfer Switch

[Speddmon]

Uh, no. I think you could drive 7.5kW load all day long, and maybe surge up to 10kW but a twin cylinder 1800RPM gen ain't gonna drive a 15kW load for any length of time.
The 003A is military rated 10kW and the civilian version doesn't have the oil cooler that the military version has and is rated at 15kW.

In my opinion you can drive loads of 1.5X military ratings near sea level at normal temps. If you try to drive 3X loads I think you will let the magic smoke out of something.

The OP is not talking about driving a 15 KW load. He as asking about "starting" or "surge" rating. And in my opinion, the 300% surge rating is probably a pretty good assumption. For the few milliseconds that the 15 KW load would be present, I think the generator and motor could more than easily handle it...as long as the main breaker holds in.

 

[derf]

The OP is not talking about driving a 15 KW load. He as asking about "starting" or "surge" rating. And in my opinion, the 300% surge rating is probably a pretty good assumption. For the few milliseconds that the 15 KW load would be present, I think the generator and motor could more than easily handle it...as long as the main breaker holds in.

I'll defer to your experience over mine. But, I don't think the windings in an 002 will take a 15kW load for any period of time, not even a surge of just a few seconds. Even if we suppose the windings could take the load, the motor can't deliver the horsepower required to generate 15kW.
In general, surge of 150% of rated output might be expected, in my opinion.

My thoughts on MEP-002s are:
Military rating: 5kW.
Civilian rating would be about 7.5kW.
Expected load capability is about 7.5kW
Probably short term surge capability would be about 10kW

This is assuming normal resistive loads.
I'm sure someone has load bank tested MEP-002s. If anyone has tested and found them to do 15kW surge, please correct me.
I am by no means an expert or authority on the subject. I try to represent facts as I know them to be facts and represent my opinions as such.
I welcome correction of either facts or opinions.

Cheers,
Derf

Edit:
I've also read where some claim that inrush current for some motor starts is up to 5X the motor's running current. Many times this 5X greatly exceeds the current rating of the circuit breaker supplying the motor. In such cases as this it might be possible for a 300% surge rating, but not for any real period of time.

 

[RWG421]

Starting the 3 ton A/C will be the test I guess. So if the A/C pegs the gauge when it starts, but settles down to 120% + - . This would be a A acceptable long term load?

All this calculating and I haven't had time to see if they run yet. They have 2.9 hours and came with the original log book, TM and packing slip from hollinsworth 1983. Filters are all unused and oil looks like honey.

Can I assume these are new units that have been sitting in storage for 28 years? or am I dreaming. Cant find a rebuild plate either.

 

[derf]

Almost certainly rebuilt. You would not want them if they had been sitting for 28 years.

According to the link below you need 7.5kW "real power" for a 3 ton AC. I think you have that with the 002.
Generator Sizing for Home or Commercial Use

Best just pose the question:
Has anyone run a 3 ton AC with their 002?
I'm sure someone has tried. I think it would work, but I don't have an 002 or 3 ton AC.

 

[RWG421]

Is there any definitive way to tell if it was a rebuild or new(28 years old/new)?

When they rebuild them how far do they go, I mean is there a "replace all SOP" or just fix whats broke and send back into service.

 

[derf]

The make motors like new. My MEP-016D had a new Yanmar motor put on a gen head from 1969. They keep the old gauges, frame, and stuff but I think the motors are essentially completely rebuilt.

 

[RWG421]

I will have to post some pics later, and if you could give me your opinion that would be great, thanks for all the advice.

 

[Keith_J]

Is there any definitive way to tell if it was a rebuild or new(28 years old/new)?

When they rebuild them how far do they go, I mean is there a "replace all SOP" or just fix whats broke and send back into service.

Usually, rebuilds have a depot facility tag attached to the unit. And new Hobbs meter is installed.

Engines are rebuilt as required. Windings are tested, inspected and repaired. Bearings replaced. Look in the -24 at the SMR code's maintenance level. Anything with a D is tested/inspected or replaced.

 

[RWG421]

Here are the pics, Tags look like they were recently removed( Shiny scratches) Your thoughts, New, rebuild whats the log book- form telling me?

Thanks,

 

[Speddmon]

Edit:
I've also read where some claim that inrush current for some motor starts is up to 5X the motor's running current. Many times this 5X greatly exceeds the current rating of the circuit breaker supplying the motor. In such cases as this it might be possible for a 300% surge rating, but not for any real period of time.

That is not just a claim, more like fact. The rule of thumb I was taught for starting inrush on an A/C motor was 6 times the FLA of the motor. That's why your motor protection is always time delayed. The inrush alone would blow a fast acting fuse instantly.

Also, it's not for any real length of time. The starting current of an A/C motor is only present for a matter of about 50 to 75 milliseconds. Once the motor starts to turn and come up to speed the current drops dramatically.

On to the OP's conundrum about the 3 ton AC unit. Put a "hard start kit" on the AC unit and you will have a pretty good chance of starting it right up without incident. The hard start kit doesn't lower the needed inrush of current, but rather creates a phase shift and greatly reduces the amount of time the current is present, possibly down to as short as 25 milliseconds.

I wish I could give you a better idea if it will work for you, but I can tell you this. At work during our power outage this summer, we started our 2 ton A/C unit (with a hard start kit installed) with a civi 6600 watt genny. As well as had a fridge, several lights and even some 500 watt quartz lights all plugged into it at the same time.

 

[storeman]

Speddman,
You are making me feel good about deciding to go with MEP-002a's instead of reworking my MEP-003a donor unit. Now if the heads interchange, I'm off to the races. If not, off to the machine shop. Thanks for your first hand observations and your introduction to Gimpy Robb.
Jerry

 

[Keith_J]

Here are the pics, Tags look like they were recently removed( Shiny scratches) Your thoughts, New, rebuild whats the log book- form telling me?

Thanks,

That generator probably never went to the field. How many hours on the Hobbs?

I can tell my 002a was with a NG/Reserve unit based on age and the shoddy fuel system condition. Around 1400 hours, based on MFG date, it only saw 2 weeks a year running. I pulled the valve cover, like new condition there, meaning light use. But the valves were adjusted all wrong, supposed to be 7 thousandths exhaust, 10 thousandths intake. They were #1 at 14 thousandths and #2 at 10 thousandths. Not harmful to valve life, just a tad noisy.

Other "horse's teeth" to look for are load terminal wear, skid bottom wear and anodized data plate bleaching. of course the main lifting eye and the fork skid tunnel wear are a good sign. Most of the time, we used recovery vehicle (wrecker) boom to load and off load. But if trailer mounted, that won't be present.

Hours don't hurt these generators, poor care dooms them.

 

[RWG421]

2.9 hours on the Hobbs, Plate has been removed, Why ??? got me. I'll poke around for the items you mentioned.

Thanks,

 

[derf]

A hard start kit helps the compressor start.

Inrush current (LRA) of a motor that a gen will start does not translate into generator surge rating, IMO.
Generator surge rating, IMO, should represent what a gen can handle for 2-5 seconds or a few minutes per hour.

Maybe apples/oranges.

 

[Keith_J]

2.9 hours on the Hobbs, Plate has been removed, Why ??? got me. I'll poke around for the items you mentioned.

Thanks,

The overall condition plus the yellow stenciling screams new. 2.9 hours? You lucky skunk.


I was fixing the rust outs on the tank of my 002 today. Using the flap wheel to knock the paint off, I uncovered the yellow stenciling under the top coat of CARC.


I'm really jealous. I still have to solder, then seal the fuel tank, replace the frequency meter, filter gaskets (filters are new), clean the fuel pumps (yeah, you should do this) and loom the wiring. Oh, and paint the generator head, it is now stripped of all rust.

 

[derf]

I hope you wore a good respirator when removing that CARC.

 

[Harleyd315]

I fired up my 002A today and hooked it up to a military A/C unit. Its a 208 3phase Zeks 36,000 BTU base mounted unit. I think this is comparable to a 3 ton unit. The 002 got it running for a minute then tripped the main breaker, gave it a few minutes rest and hit it again this time it ran for about a half hour before the breaker popped. Each leg was drawing about 21 amps by my probe. The gauge indicated 120% output. The machine did sound like it was breathing heavy but no black smoke from the exhaust. I think the motor and gen head could probably handle the extra load but, the main breaker is there to protech some thing? Wiring? Hope this helps on making a decision of sizing your gensets. P.S. My 004 ran the A/C unit for about 2 hours and didn't know it was there.

 

[cranetruck]

Yes, it is kind of important to keep the loads in balance. Depending on what you are doing with it though, you may not need to worry about it too much.

If you are running it in 120/240 single phase mode, and have your house hooked to it. Any 240 volt loads are automatically balanced. The 120 volt loads are the only ones you need to worry about. Other than maybe a well pump or sump pumps, most of your 120 volt loads are going to be small loads such as light bulbs and possibly electronic devices with little current draw. It will take a lot of bulbs burning on just one leg of the generator to imbalance the phases bad enough to cause troubles......

Could you expand on this, possibly? My mep018a 10KW genset head "burned out" after some 25 hours of good performance (over a 6-months period) and I have assumed that it was due to a handfull of dirt and gravel discovered inside, but perhaps it was as a result of imbalanced loading. We often operated a welder and other power tools from this unit.
TIA

 

[Speddmon]

Bjorn,

If the unit was running in 120/240 volt mode and the welder is a 120 volt model that could explain the head going bad so soon. The welder and power tools would put a pretty large unbalance in the generator. some power tools like a good circular saw or angle grinder can draw upwards of 13 amps. The welder could easily draw 20 to 30 depending on size and amperage settings of the welder. The power tools alone would imbalance the windings enough to heat them up to the point of insulation breakdown. I won't even claim to know enough about the inductive forces at work inside of an imbalanced generator to tell you exactly why the need to be balanced, but too much of an imbalance will cause excessive heat. Heat and varnish insulation do not play well together.

 

[cranetruck]

Bjorn,

If the unit was running in 120/240 volt mode and the welder is a 120 volt model that could explain the head going bad so soon. The welder and power tools would put a pretty large unbalance in the generator. some power tools like a good circular saw or angle grinder can draw upwards of 13 amps. The welder could easily draw 20 to 30 depending on size and amperage settings of the welder. The power tools alone would imbalance the windings enough to heat them up to the point of insulation breakdown. I won't even claim to know enough about the inductive forces at work inside of an imbalanced generator to tell you exactly why the need to be balanced, but too much of an imbalance will cause excessive heat. Heat and varnish insulation do not play well together.

We used the "convenience" outlet for all 120VAC needs and it has a 15-amp fuse, which never blew The welder was a wire feed type, don't know the rating...the circular saw and the miter saw could be close to 15A, though.
For this use, there was nothing connected to the 240VAC output.