Purpose of Synchronizing transfer on MEP-803a generator trailer

[muthkw25]

I have a friend that just bought a Joint Electronics MEP-803a trailer with two MEP-803a generators mounted to the trailer. He doesn't know alot about the setup so I am trying to get some info on it. On the trailer, there are two large cables that go into a box that says synchronizing transfer for both generators. My question is does synchronizing the generators double voltage or amperage? What type of application would require something like that? And could you just disconnect the two generators and run them separately? thank you in advance...Kyle

 

[NDT]

In military applications, that switch typically switches (transfers) ALL the load from one generator to the other so maintenance can be performed on one generator. The switch on older generators transferred the load without regard to whether or not the generators were in synchronization. Synchronization mean that the waveform of the alternating current of each generator matches before the switch is thrown. The switch you have would appear to indicate somehow that the generators are synchronized before the load is switched. This is preferred with motors and solid state devices.


Sure you can run the generators separately. You can also run them together, that doubles the amperage available, but as mentioned, they have to be in synchronization before you can connect them together or bad things happen. Google "Aurora Experiment" to see what happens to a generator when they are connected out of sync.

 

[muthkw25]

Thank you for the information. I wonder why the government would put two generators on the same trailer. I can't imagine they would require that much constant maintenance would they?

 

[NDT]

The mil sites need power with 100% reliability or soldiers die. In combat you can't drop power to a hospital or radio station because you need to add a quart of oil after a generator has run 30 days straight.

 

[Daybreak]

Howdy,
A military power plant is for 100% uptime for electrical service.
The smaller dual 5kw, and dual 10kw power plants do not have the smarts for parallel load sharing. The dual units are meant for a quick easy transfer of power between units. That way the oil and filters and such can be worked on.

Dual MEP-804A 15kw, MEP-805A 30kw, MEP-806A 60kw all have the smarts for parallel load sharing. That means 2 units can work in unison sharing a load.

The newer 3rd generation AMMPS generator have built in load sharing from 5kw and up. Just need to use matching units. Such as 2 5kw AMMPS units could parallel load share 10kw, and 2 10kw AMMPS units could parallel load share 20kw.

AMMPS units can be combined with like units in higher multiples too.
3 5kw AMMPS units could parallel load share 15kw etc...
3 10kw AMMPS units could parallel load share 30kw etc...
3 15kw AMMPS units could parallel load share 45kw etc...

 

[muthkw25]

Howdy,
A military power plant is for 100% uptime for electrical service.
The smaller dual 5kw, and dual 10kw power plants do not have the smarts for parallel load sharing. The dual units are meant for a quick easy transfer of power between units. That way the oil and filters and such can be worked on.

Dual MEP-804A 15kw, MEP-805A 30kw, MEP-806A 60kw all have the smarts for parallel load sharing. That means 2 units can work in unison sharing a load.

The newer 3rd generation AMMPS generator have built in load sharing from 5kw and up. Just need to use matching units. Such as 2 5kw AMMPS units could parallel load share 10kw, and 2 10kw AMMPS units could parallel load share 20kw.

AMMPS units can be combined with like units in higher multiples too.
3 5kw AMMPS units could parallel load share 15kw etc...
3 10kw AMMPS units could parallel load share 30kw etc...
3 15kw AMMPS units could parallel load share 45kw etc...

Thanks Mike, I appreciate the information.

 

[Guyfang]

Send a picture of the rig. Mike is 100 % right. The 802 and 803 can not be used in parallel.

 

[mlaxton]

So I got a pretty good deal on two mounted 802a the other day. This was also mig Ted on the trailer and they were hooked into it. I bought have an 803a already and wanted to get my hands on an 802a for running at night because not much power is used at night. Just a central AC. When I started investigation into what this device is I got excited. My question would be, can this be used to transfer power from my 803 at night to an 802 and back in the morning? Without chatting everything down? Obviously you would just have to make sure when you transfer the load to the 802 everything is off for the night. Is there any reason this wouldn’t work in that way?

 

[Guyfang]

The TM says that you can only use it for LIKE items. Two 802A's or two 803A's. In theory it should work. I have never tried it with two different gen sets. Hook it up and try it.

This is the old style box. What PP, (Power Plant) did it come on.

 

[mlaxton]

The TM says that you can only use it for LIKE items. Two 802A's or two 803A's. In theory it should work. I have never tried it with two different gen sets. Hook it up and try it.

This is the old style box. What PP, (Power Plant) did it come on.

Two reset 802a’s

 

[mlaxton]

The TM says that you can only use it for LIKE items. Two 802A's or two 803A's. In theory it should work. I have never tried it with two different gen sets. Hook it up and try it.

This is the old style box. What PP, (Power Plant) did it come on.

You think they recommend only like units because of what I said a couple comments up? If it’s to like generators then obviously the one you’re switching to can handle the load you currently have on the other one. You would just have to be aware of what load was on the 803 before you switched it over?

 

[Guyfang]

You think they recommend only like units because of what I said a couple comments up? (Can not tell you why. Never thought to ask.) If it’s to like generators then obviously the one you’re switching to can handle the load you currently have on the other one. You would just have to be aware of what load was on the 803 before you switched it over? (Like I said, try it if you want. Just get it hooked up right)

 

[Ray70]

I'd agree. In theory there should be no reason it wouldn't work as long as the load is ok for the 802.
You can easily try it using a dummy load, if you are worried about it not working right.

 

[Poccur]

Some applications want both plants running at the same time to guarantee power in the event of one unit dying...as said the maintenance swap-over is useful but when the higher ups are inspecting you turn both on at the same time Never a good time to go dark in the TOC...

 

[Guyfang]

Case in point. Patriot Missile System. During the first Gulf War, The Patriot Battery's were instructed to run both 150 KW Turbine gen sets, at the same time, due to the unreliability of the gen sets. That also had a bad side effect. You could set your watch by a D424A gen set, destroying itself at 1000-1200 hours. Engines were about as easy to get as hens teeth. There were only 3-4 spare engines total. Didn't take long, and the units were only running one gen set at a time, because they only HAD one left instead of two at each unit. Didn't take long, and we had to ask our German friends to loans us there EPP's, (Electric Power Plants) to cover our butt. The Germans were not stupid enough to buy the turbine engine. They bought a gen set with a Klockner-Humboldt-Deutz motor. There was one insistence, where a Battery lost power on a firing run. There was loss of life, due to the unit not being able to fire its missiles.

Most small gen set applications are only meant for switching power, not for running in parallel.

 

[rorub]

I have been unable to locate the TM for this device. Would this allow parallel operation of like generators? Two 803/003s?

 

[Guyfang]

I have been unable to locate the TM for this device. Would this allow parallel operation of like generators? Two 803/003s?

Read the last sentence of the post above yours. Yes, I can give you the TM, in fact, its in the TM forum I think. But its no good for small gen sets.

 

[rorub]

Read the last sentence of the post above yours. Yes, I can give you the TM, in fact, its in the TM forum I think. But its no good for small gen sets.

Thanks, I read the thread. I was just wondering if would allow parallel operation in the same way a member here demonstrated in their video.

I don’t have an immediate need to run the gensets in parallel, but I would have this on hand in case I ever needed to.

 

[Guyfang]

What video? I would like to see what he is doing, and maybe read the thread.

 

[Ray70]

Neither of those small 5+10 Kw synchronizers allow you to parallel 2 machines, just synchronize the frequency then shift the load from one machine to the other. You can not have both machines on-line together.
The small machines are different than the larger ones which are designed to be paralleled together.
You can physically parallel 2 small machines using several different methods that folks have posted on-line, but most of these methods are not really good for the machine.
There is a video out there where someone uses the voltage regulator from machine to control both machines. This would probably be better than simply forcing both machines to fight each other due to slight differences in voltage and frequency, but I'm not electrically smart enough to know how well that would work either, long term.