NEW TO MEPs-802 GENS

[Papi Chulo]

Does anyone know what this switch-box does? I bought two MEP-802a connected to this box and from what I can gather, it synchronizes the units but I don't know why. Is it to up the 5Kw to 10 Kw?

I've looked online but most the information I find is kinda vague, tells me how to hook it up but no reason as to why.

 

[loosegravel]

From what I’ve gathered, the MEP-802A units and the MEP-803A units cannot be paralleled for combined total power due to the nature of the mechanical governors. They cannot be synchronized. This box is simply to be able to switch from one generator to the other for a seamless, uninterrupted power supply. The larger units with electric governors are capable of running in parallel for combined power output because of the electric governors.

 

[loosegravel]

There maybe someone on this forum who could use this device if you don’t have a need for it. You can post an ad in the classified section either in items for sale or the pay it forward section if you simply want to give it away.

 

[Papi Chulo]

THANK YOU VERY MUCH! It makes total sense now!

 

[Papi Chulo]

There maybe someone on this forum who could use this device if you don’t have a need for it. You can post an ad in the classified section either in items for sale or the pay it forward section if you simply want to give it away.

I might end up selling it. I live in Florida and bought the MEPs only for as stand-by gens and don't really see the need to worry about disrupting power to the house if I need to work on any of the gens.

Thank you very much for the info.

 

[loosegravel]

This is really a great forum. People here are so willing to offer their experience. You will also find a lot of great information relating to your specific units in the TM section too. Welcome aboard!

 

[Light in the Dark]

I'm pretty sure you can use the fender box with mixed Genset sizes... It's just a matter of knowing the amperage being drawn at the time of changeover.

Safety dictates that the gensets be equally sized to take any chance out of an overload situation upon changeover... But someone with a solid understanding of what the box does, and the true load being shifted, should be OK in mixing.

YMMV

 

[Papi Chulo]

I'm pretty sure you can use the fender box with mixed Genset sizes... It's just a matter of knowing the amperage being drawn at the time of changeover.

Safety dictates that the gensets be equally sized to take any chance out of an overload situation upon changeover... But someone with a solid understanding of what the box does, and the true load being shifted, should be OK in mixing.

YMMV

Rodger that! Thank you!

 

[DieselAddict]

I have a trailer with that same box. I'm selling off the generators that came with it and putting my own units on the trailer. I plan to put on a 10kw and a 5kw. The box will work with either size. It has 100 amp contactors in it.

The box allows for seamless transfer of loads between generators. As stated above if you have different sized machines, you would need to make sure you aren't about to cause an overload if transferring to the smaller generator. I Switching between generators is a semi-automatic operation. The box won't switch unless the generators are in sync but the operator has to hit the buttons to initiate the switch. The instructions are on a tag on the box.

In my case I'm not primarily going to use it to transfer loads between generators but to select a running generator to connect to the loads. I'll be using a controller to automate the switching functions in the box.

 

[Guyfang]

From what I’ve gathered, the MEP-802A units and the MEP-803A units cannot be paralleled for combined total power due to the nature of the mechanical governors. They cannot be synchronized. This box is simply to be able to switch from one generator to the other for a seamless, uninterrupted power supply. The larger units with electric governors are capable of running in parallel for combined power output because of the electric governors.

This is not quite true. The box synchronizes two like generators. It will not let you parallel the sets. That's two different functions. If you want to know how to use it, its in a TM. Tell me what PP, (Power Plant) and I can direct you to the TM for it.

I'm pretty sure you can use the fender box with mixed Genset sizes... It's just a matter of knowing the amperage being drawn at the time of changeover.

No, its not supposed to be used for two different sized gen sets.

Safety dictates that the gensets be equally sized to take any chance out of an overload situation upon changeover... But someone with a solid understanding of what the box does, and the true load being shifted, should be OK in mixing.

 

[Guyfang]

I have a trailer with that same box. I'm selling off the generators that came with it and putting my own units on the trailer. I plan to put on a 10kw and a 5kw. The box will work with either size. It has 100 amp contactors in it.

The box allows for seamless transfer of loads between generators. As stated above if you have different sized machines, you would need to make sure you aren't about to cause an overload if transferring to the smaller generator. I Switching between generators is a semi-automatic operation. The box won't switch unless the generators are in sync but the operator has to hit the buttons to initiate the switch. The instructions are on a tag on the box.

In my case I'm not primarily going to use it to transfer loads between generators but to select a running generator to connect to the loads. I'll be using a controller to automate the switching functions in the box.

What I should have wrote is that CECOM tells you that it is not for use by different sized gen sets.

It allows for seamless transfer, but not paralleling. If you could parallel, then the size of the sets being used can differ, but should NEVER be smaller the the max output of the smallest set.

 

[loosegravel]

From what I’ve gathered, the MEP-802A units and the MEP-803A units cannot be paralleled for combined total power due to the nature of the mechanical governors. They cannot be synchronized. This box is simply to be able to switch from one generator to the other for a seamless, uninterrupted power supply. The larger units with electric governors are capable of running in parallel for combined power output because of the electric governors.

This is not quite true. The box synchronizes two like generators. It will not let you parallel the sets. That's two different functions. If you want to know how to use it, its in a TM. Tell me what PP, (Power Plant) and I can direct you to the TM for it.



I'm pretty sure you can use the fender box with mixed Genset sizes... It's just a matter of knowing the amperage being drawn at the time of changeover.

No, its not supposed to be used for two different sized gen sets.

Safety dictates that the gensets be equally sized to take any chance out of an overload situation upon changeover... But someone with a solid understanding of what the box does, and the true load being shifted, should be OK in mixing.

Thanks for that clarification Guy!

 

[Ray70]

I've got one of those same transfer switches hooked up to 3 of my machines. I've got a shed set up with an 002 and 003 and an 831.
Only reason I have the synchronizer installed is that I had 2 sitting around and thought it would be a cool ( yet unnecessary ) feature to be able to switch between 10K 5K and 3K sources, based on the time of day / load. So if I'm running a 10K during the day and want to switch to a smaller gen for the night to keep just the fridge, heat or lights on I can just synchronize the sets accordingly and flip the switch without the TV or computers flinching. BUT... as said above, you have to limit you max load ahead of time so you don't overload the smaller gen.

 

[Daybreak]

In a more layman's terms.
It is meant for keeping 100% uptime of power.
#1 generator is running, and it needs to be serviced. #2 generator is fired up, use the box to sync, transfer, shut down #1 generator and service.

 

[Guyfang]

That was the reason it was installed.

 

[Light in the Dark]

No, its not supposed to be used for two different sized gen sets.

Supposed to, and can, are different beasts... but clearly its inherently safer to keep it as CECOM says with like sets to remove one less bad decision waiting to happen.

 

[DieselAddict]

From what I’ve gathered, the MEP-802A units and the MEP-803A units cannot be paralleled for combined total power due to the nature of the mechanical governors. They cannot be synchronized. This box is simply to be able to switch from one generator to the other for a seamless, uninterrupted power supply. The larger units with electric governors are capable of running in parallel for combined power output because of the electric governors.

The mechanical Governor isn’t a big problem. Once the machines are connected together if the governors are reasonably setup they won’t surge. The AVR is the real issue with paralleling these sets. You need an AVR setup that can do a master/slave relationship to prevent reverse power on a generator. You’ll cause carnage in the exciter If the AVRs aren‘t in sync.

I’ve watched a rotating diode assembly go up in smoke on a 2 MW set when the AVR had the incorrect settings programmed during a peak shaving test with the generator running in parallel with utility power. The BS the tech started spouting to deflect the blame was amazing. I let him go through his entire performance then asked one question, can you show me the reverse power protection setting? The look on his face was priceless. He knew he was busted. Anyway, a $2k diode assembly (at their cost) from CAT later and we were back in business.

 

[Guyfang]

That's why the CECOM called for two, (sometimes three) different sets. The Utility, The Precise and the 400 hertz sets. Precise sets, ( The 400 hertz sets were also able to Parallel.) are the sets to be paralleled. Utility not. Example, MEP-006A Utility, MEP-105A Precise, and the MEP-115A Precise 400 hertz.

 

[Jon Hanson]

I've got one of those same transfer switches hooked up to 3 of my machines. I've got a shed set up with an 002 and 003 and an 831.
Only reason I have the synchronizer installed is that I had 2 sitting around and thought it would be a cool ( yet unnecessary ) feature to be able to switch between 10K 5K and 3K sources, based on the time of day / load. So if I'm running a 10K during the day and want to switch to a smaller gen for the night to keep just the fridge, heat or lights on I can just synchronize the sets accordingly and flip the switch without the TV or computers flinching. BUT... as said above, you have to limit you max load ahead of time so you don't overload the smaller gen.

Sirs: I just purchased a 2012 Fermont MEP-803A, 10kW, 60 Hz, Generator Set,

NATO Tactical Quiet, Skid Mounted on a Super Single Chassis 2 1/2 Ton, 2-Wheel Trailer.

So far it looks like it has a good ONAN 4-Cyl. 24.1 HP Diesel Engine in it that turns over

when using the “Dead Crank Switch” . I have installed 2 new 12V DC, 850 Ah battery’s

in series to get a very good 24Vdc source. I have also done a New Oil and Filter change and filled

up with fresh diesel fuel. At this time my goal is to just RUN the engine for 3 or 4 minutes.

My problem: I noticed that all 6 of the enclosed relays S14, K12, K15, K16, K9 and K20

are all missing along with the “cartridge 30A fuse Item #22 and #23”.

Question: Do I need all of these items just to run the engine only?

The engine will turn over, but not run when using the Item #16 Master Switch on the Control Panel.

I know I do need all of them to run the Generator, but I just want to know the engine is ready to go.

I am open to all suggestions, Thank you Sirs from Jon Hanson . . . San Antonio, Texas.

 

[Light in the Dark]

If it cranks over strong by the dead crank, thats a good start. You do need those relays and switches. If you really just want to hear the engine run, it is possible if you really need to before buying up the right parts. You can use the dead crank to turn it over, and manually pull on the fuel stop solenoid and hold it to the open position (to the right). Its the barrel item, with flat metal armature, that ties to the little arm near where the frequency cable mounts.

I recommend you get the right parts in place first though, and save the running till all items are installed correctly.