MEP 005A Emergency shutdown

[Pugsley]

I have a now working MEP 005a and was wondering what happens when the generator shuts it self down for low fuel... or anything else that causes a shutdown. Does it automatically open the main breaker disconnecting the load from the generator or does it stay closed?

It had issues that I was able to fix using info found here but I can't seem to find any info about this and do not want to subject things in the house to a winding down generator.

Thanks.

 

[Ray70]

In the case of a fault, power disconnects immediately at the magnetic circuit interruptor.
Depending on the fault condition the engine may or may not shut down.
Things like over voltage, over current etc. only disconnect power, they don't shut down the engine.
Low oil pressure, low fuel, over temp etc. those will kill the power and shut off the engine.

 

[Pugsley]

Ok cool. So it will open up the breaker if it runs out of fuel and shuts down. That is one less concern I have about it.

Thanks for the info.

 

[Ray70]

Correct. it will never throw a fault and then slowly wind down to a stop with the power still ON.
However.... it is possible to have mechanical failures that could lead to some degree of engine slowing down before power disconnects.
A mechanical failure with the IP for example, or a plugged check valve in IP fuel return line will cause the motor to die, but it may not throw a fault immediately. It may eventually throw a fault as the power dwindles down, but it will not be immediate like it would in the case of the other fault conditions.

 

[Guyfang]

Well, if the system sees under freq, it will shut down the CB. I have never seen any 004A, 005A or 006A do anything less. One of the few parts I never saw go bad, was the under volt relay.

Pug, a quick look at the -12 TM should tell you when it will trip.

 

[Pugsley]

Thanks again for the replies. A few other questions... I know that if i leave it configured for 3phase I can only get about just under 2/3 capacity running it as single phase... and that wont hurt anything... or a can "dog leg" it and get near full capacity. I guess my question is running it configured for 3 phase and using it for single phase wont hurt anything as long as a stay below 2/3 capacity? I understand the whole 208 3ph vs the 240 dog leg thing. just don't want to hurt anything running it in 3p mode and powering singe phase stuff. I still have a use for 3p (shop stuff) so I don't want to dog leg it if I don't have to.
And what leg is the convenience outlets wired to?

Thanks again for all the help.

 

[Guyfang]

The 120 volt outlet is normally hooked to L3, if I remember right. Ray?

 

[Ray70]

I believe that is correct Guy.
So I assume your thought here is to run your single phase 240 ( technically 208 single phase ) off L1 and L2, then throw some other misc. 120V single phase loads on the courtesy plug ( or L3 /L0 directly ) to get a little more power and help balance things out a little?

 

[Pugsley]

Does It need to be balanced to prevent damage to the main generator? If so then yes I can put some junk load on it... or I might come up with a little wiring and switches trick to be able to flip back and froth between normal 3p and dog leg. I don't want to modify it if I don't have to. That's why I was asking if running 2 legs for "single phase" will hurt anything. I can't imagine in the winter running it close to 20kw. more like 6-8 as everything is gas in the house. The biggest load would be the.... fridge, furnace (on different legs) and well (240/20. Then a few lights and TV. So if I can get away with running it on L1 and L2 only while configured for 3P that's what I will do. Mainly I just want the well and sump to work if we get a huge storm.

I have things pretty well balanced as far as 120 loads go in the house.

I think i have some halogen work lights I can plug in to the courtesy outlets to try to balance it out if need be. But would prefer not to if I don't need to.

Oh yeah forgot to mention that this will be back feeding the house through the barn breaker and is only rated for 30 amp so only around 7KW total before that would trip. So that is in theory the max load I can even put on the generator. It all going to be manual and ill have a check list made up to go through to operate it all. I know make sure the MAIN breaker is off so I don't murder any linemen by back feeding the grid.

Thanks again for the info and help.

 

[Ray70]

Well, a balanced generator is a happy generator, but.... it will still function perfectly fine with just the 2 legs being utilized, especially with your light load.... Which bring up the whole Wet Stacking issue.
Your relatively little load on a 30K will lead to wet stacking and black goo dripping out of the muffler, so you should design a way to load it up good occasionally to clean everything out.

 

[Pugsley]

Down at the railroad museum we have some old 3p equipment that we can't use as our phase converter is not big enough.... but that wont be an issue with this generator. So it will get loaded well when used to run that equipment.

 

[Scoobyshep]

short circuit will trip cb2

undervolt, underfrequency, reverse power, overload, permissive parallel will trip cb2 but are bypassable with battle short

low fuel, water temp, oil pressure, overvolt will kill the engine which also trips cb2