MEP-002A or MEP-003A

[jbk]

or just add another gen. set to the mix for when loads are light. can never have enough generators.

 

[Stalwart]

Those numbers sound great George!

JBK, that is easy for separate and independent loads but not for a house or shop. You'd need to assign a master generator and a control that would allow any other generators be slaved to it. Not only would you need to balance the voltage but they must must operate at the exact same frequency and be "in phase" with each other. You can't just parallel multiple AC generating systems and expect it to work out, it won't! They have to do this with the AC Generators in large aircraft, luckily there is a CSD (Constant Speed Drive) to allow the frequencies and phases to be matched and locked.

 

[Keith_J]

Hi Stuart,

Thanks for the info. She runs, boy she sounds great. Followed starting instructions on the door, instant start.
Temp is about 180 degrees with the louvers closed. Oil pressure about 58-60 PSI

I am 50 but feel like a kid with a new toy HA.

All I have to figure out is the L1 L2 L3 GRD connections. Which combinations gives me the desired volts.

Cheers, George

L1 to L0, L2 to L0 and L3 to L0 will give 120 volts each when connected for 208/120 volts. L1 to L2, L2 to L3 and L3 to L1 will be 208 volts. But you must balance loads on each phase within 5%.

You need a basic generator operations course before employing such a set for single phase operations. You will have to read a lot of posts here and at the Smokstak.

 

[dutchboypower]

question about the main load contactor .
I have voltage at a1 b1 and c1 220v
But at a2 b2 c3 show 0 volts.

Do I only show volts at those connections when a load is connected.
I checked for open circuits, but all seems to be fine.

My convenience receptacle is working fine 121v +/- 1 volt

www.logsa.army.mil

Thanks for the link guys, was able to download the operators manual.

Thanks, George

 

[dutchboypower]

question about the main load contactor .
I have voltage at a1 b1 and c1 220v
But at a2 b2 c3 show 0 volts.

Do I only show volts at those connections when a load is connected.
I checked for open circuits, but all seems to be fine.

My convenience receptacle is working fine 121v +/- 1 volt

www.logsa.army.mil

Thanks for the link guys, was able to download the operators manual.

Thanks, George

 

[dutchboypower]

The front panel gauges show the correct values . 60Hz +/- 1Hz and 120V

So I do not think I have to re flash the field.

 

[dutchboypower]

Got it all is well.
I did not hold the circuit breaker up until the yellow light comes on.

Was reading some more through the ETM manual.

Regards,

 

[Keith_J]

question about the main load contactor .
I have voltage at a1 b1 and c1 220v
But at a2 b2 c3 show 0 volts.

Do I only show volts at those connections when a load is connected.
I checked for open circuits, but all seems to be fine.

My convenience receptacle is working fine 121v +/- 1 volt

www.logsa.army.mil

Thanks for the link guys, was able to download the operators manual.

Thanks, George

Where and how did you measure the 220 volts AC? I don't mean to scare you but you are dealing with something that will easily kill you.

First, only operate if grounded. See TM. Regardless if the breakers are on or off, the voltages you measured are being generated in the stator and could easily break insulation and pose shock hazard.

Second, the voltages are relative to each other. Birds sitting on an uninsulated electric line are at line voltage, they are fine because there is no voltage difference so no current flow.

Three phase is the only connection method possible for that generator. If you don't know what three phase is, you will either destroy the generator or the electrical equipment connected to the generator. There are two connection voltages for an MEP-005A per TM5-6115-465-12, 120/208 and 240/416 volts, all three phase.

120/208 means the three legs, L1, L2 and L3 have a voltage of 120 with respect to neutral, usually L0. And the voltage between L1-L2, L2-L3 and L3-L1 is 208. The 208 volts is just 120 volts in a wye configuration, either 120 multiplied by the square root of 3 OR 240 multiplied by half the square root of three. This is all geometry of three phase...

Terminal board 6 has 12 terminals, this represents six stator windings. The six can be configured in either a paralleled wye or series wye. Parallel gives the 120/208 and series gives 240/416. Unless you know three phase generation from such windings inside and out, get a professional to wire it series delta to get 120/240 single phase.

See load terminal configuration in TM 5-6115-584-12, figure 2-4 on how the MEP-002A is connected. You have only three phase possible as currently possible.

Finally, do not rely on that convenience receptacle for any base load. Meaning you can power your shaver or cell phone charger but not your George Foreman Grille. Got that?

 

[dutchboypower]

Got it.

Thanks for the warning and info.

I am somewhat confused by this statement made on Figure 2-4

The load terminals will accommodate
2-wire single phase and 4-wire, 3
phase loads. One or more single phase
loads can be served alone or in combinations
with 3 phase loads; but the
load on any one phase must not exceed
100 ercent of the current rating

Maybe I am just being stupid, but I am going to ask the question. If I use L1 and L2 as 120V and L0 as neutral why do I not have 240 single phase.

George

 

[Wrench Wench]

Not only would you need to balance the voltage but they must must operate at the exact same frequency and be "in phase" with each other. You can't just parallel multiple AC generating systems and expect it to work out, it won't!

If you want to run two generators in parallel, you're absolutely right. It's a pain in the keister. However, there are transfer switches that can take the input from two (or more) generators, wait until a genset is up and running, stable, and generating good power, tweak the new one to get it in sync with the power being applied to the load, and then switch the new genset on to the load lines and then switch the current genset out. This is done to keep persistent power to a vital load while allowing generators to be brought online and offline so power is not dependant on one single generator. Generators can be taken off line and serviced or just load balance the wear across multiple generators.

It's what the pairs of MEP-002s or -003s on an M116 trailer have.

 

[Keith_J]

Got it.

Thanks for the warning and info.

I am somewhat confused by this statement made on Figure 2-4

The load terminals will accommodate
2-wire single phase and 4-wire, 3
phase loads. One or more single phase
loads can be served alone or in combinations
with 3 phase loads; but the
load on any one phase must not exceed
100 ercent of the current rating

Maybe I am just being stupid, but I am going to ask the question. If I use L1 and L2 as 120V and L0 as neutral why do I not have 240 single phase.

George

L1 and L2 are out of phase by 120 degrees. You won't get 240 but 208 without center neutral tap. For what you want, you would need a center tapped winding like this:

But that is delta and your generator is wye..major reconnection, paralleling two deltas.

 

[PeterD]

The term for the circuit in Keith's drawing is "high leg delta." It is commonly used for businesses where they need both three phase, and single phase power, where 240 three phase is needed. Usually the L1-N-L2 circuit is heavier than the L1-L3 and L3-L2 ones, to compensate for the additional single phase loads.

 

[dutchboypower]

So I am out of luck trying to run 120 single phase with one leg and Neutral.

Unless I am misunderstanding you guys

 

[PeterD]

So I am out of luck trying to run 120 single phase with one leg and Neutral.

Unless I am misunderstanding you guys

No, you can run 120/208 single phase from a MEP-005 if that is what you have.

Please confirm your generator model, I'm confused!

You won't get the 30 KW from the MEP-005 using one (120) or two legs (120/208 ) but that's a minor issue.

If you just want 120 volts (don't care about 208 volts) then use L0 and L1 (or L0 and L2, or L0 and L3). L0 is the center of the wye (neutral), and by default in the MEP-004/5/6 units I've seen is bonded to the generator set's frame.

It will work, it may not be practical, however.

Just a suggestion... Next time instead of injecting into an existing thread about a specific generator, start a new thread. It makes one's head hurt trying to keep track of who has what!

 

[Keith_J]

You can run 1,2 or 3 legs of 120. Or you can do the same at 240 volts with the stock reconnection panel. But you cannot get 120 and 240 like common residential service without additional equipment or reconnection modification to your set, primarily converting from wye to delta. Specifically, series delta.

This is why the 3-10 kW sets are more popular.

 

[Isaac-1]

Just a note here there was a message thread here a while back about modifications that could be made to some of these larger 3 phase only generators to allow single phase output, I forget if it was talking about the MEP-004/005 family or the MEP-006/007 family. Internally these are 12 lead reconnectable generators so can be connected for any number of voltages not directly supported by the military quick change connection board. I don't recall if this modification included any changes on the instrumentation or voltage regulator side or if it was strictly cutting and jumpering the connection board. There is also reference online to someone in the Carolina's selling surplus units pre-converted to single phase output, note typically when a 12 lead generator set is wired up for single phase its rated output is a little over 2/3 of the 3 phase rating.

Ike

p.s. Keith, I don't know if the mods use zig-zag or double delta for there wiring to get to 120/240, but both would likely work

 

[dutchboypower]

Sorry guys I will start a new tread next time.

Thanks for your help.