GENERATOR QUESTIONS FOR YOU EXPERT ELECTRICIANS

[3930dave]

TBone - if your truck has a receiver, what about one of these rxer platforms with a loading ramp ?

Hitch Cargo Carriers and Cargo Baskets

If your 240 gen has wheels (or you can strap it onto a dolly), might be easy enough for one person.

Rgds, D.

 

[BrokenTrack]

Must be from the Army Air Corps considering the Air Force began in 1947.

Or maybe a 1947 instead of a 1943? I am pretty sure it says US Air Force, but it is pretty rusted up so I could be wrong on either point...

 

[aczlan]

I could be wrong, but I understand that running a three phase capable set on single phase always means derating. There simply isn't a way around it. Unless it's maybe two generators in one, a single phase and a three phase, but that would be very wasteful and much larger than it had to be.

It depends on the set, if it's a 12 lead genset and all 12 leads are brought out, it can be configured for either 3 phase or single phase with full power for either one.

Aaron Z

 

[Industrial Toys]

I don't think that's possible. Unless maybe a third of it isn't being loaded so really doesn't cost fuel, but it would run unbalanced. I don't profess to understand how you can get single phase from the remaining two phases. Wouldn't the timing be different from a generator that makes 60 cycles with a varying equal number of poles?

I did Google it and it seems that I maybe right that you only can get 60% of the generator capacity.

 

[aczlan]

See the specs for the MEP002 and MEP003, both put out the full output on single phase or 3 phase: Steel Soldiers::Military Vehicles Supersite - MEP WIKI

It has to do with how the leads inside the generator head are wired. If all 12 leads come out and are spliced outside the head, you can rewire them to either single or 3 phase. If they are spliced inside the generator head (like most are), you can't.

Aaron Z

 

[BrokenTrack]

See the specs for the MEP002 and MEP003, both put out the full output on single phase or 3 phase: Steel Soldiers::Military Vehicles Supersite - MEP WIKI

It has to do with how the leads inside the generator head are wired. If all 12 leads come out and are spliced outside the head, you can rewire them to either single or 3 phase. If they are spliced inside the generator head (like most are), you can't.

Aaron Z

This makes sense as there is a box that is bolted to the generator, and the leads are inside that box. The box then has switches inside it that switch it over from single to 3 phase.

 

[Industrial Toys]

Then explain the physics to me, because I don't think it's possible. If it's a three phase alternator, you can only get 60%. Unless it's actually wound as two alternators, single and three phase. I wouldn't doubt it for the military, but I think it's unlikely.

 

[CobyRupert]

Then explain the physics to me, because I don't think it's possible. If it's a three phase alternator, you can only get 60%. Unless it's actually wound as two alternators, single and three phase. I wouldn't doubt it for the military, but I think it's unlikely.

It's been awhile...but...
Let's say it's a 3 phase, 2 pole (3600 rpm) generator like I think I show below. (Phases are "A", "B" & "C". "2 Poles" of phase A are labeled "A1" & "A2"; 2 poles of phase B are labeled "B1" & "B2", etc... p.s.: Notice how A1, B1, C1, etc.. are all 120 degrees out of phase with each other because this is 3 phase)

A picture can better describe.

I think if you connected together all the windings on the bottom half in series to form 1 big pole, and all other windings on the top half in series to form (the other) pole, you'd have a single phase, 2-pole, genny with full capacity:

 

[Industrial Toys]

I could be wrong, just sayin. But that sounds like a great big short! Trying to get a hold of the guy that rewinds my generators for his input. Because I would really like to know.

 

[Industrial Toys]

I saw something on wiring a zig-zag configuration on a MEPS 12 terminal type genset. It was not well explained. I am interested and will try and find something to make me understand it. Always interested in understanding how things work as opposed to just believing what I am told.

So do MEPPS sets typically have more windings than a run of the mill 3 phase alternator? Not that I yet understand the phase implications.