SEORTM Shop truck gen problems - Any help? No output. Model Lima MAC 3165-0083

[Valleyordnance]

Hi guys,

I bought the SEORTM M844A1 shop truck out of Fontana a couple weeks ago. Got lots of goodies with her but I bought a few problems too...

I can engage the PTO, and get the gen head turning. It has a 25KW Lima MAC PTO driven Alternator w/ distribution panel. Gen head PN# is 3165-0083. I've got no juice on any of the output leads. I know enough about general electrical to keep from getting zapped and know where and how to read voltage with a DVM.

I have read threads about the smaller MEP03's needing the fields flashed. Is this applicable to a larger gen head as well? I have ZERO experience with gen sets. I have read about the electric drill method, also using a 12V battery. I'm a little leery about trying either as I don't know enough to know if this may damage the gen head.

Any input from any experts or somebody who's done this? If it's not the field where do I look next? I can't find a current TM for the SEORTM shop body. The manuals on the net are circa 1972 and the gen panel is completely different. So, anybody got a TM or know where to find one would be great as well!

Thanks!

Chris R in Phoenix

 

[dependable]

Here is manual for PTO driven 12.5KW Lima Mac from 1031. Its principal of operation is probably similar. Hope it helps.

It is supposed to be self exited. The diodes can get fried, but are replaceable. There are flashing instructions in manual as well.

 

[319]

Not familiar with the SEORTMs, post photos of your control panel. On the older models (SGPRSMD), to get power from the generator, certain breakers had to be on, and a four position rotary switch had to be in the correct position for generator, shore power, etc....

 

[Valleyordnance]

The SEORTM Panel that is used now is fairly stupid proof. Master breaker to energize from the genhead or from shore power (with a sliding lockout). I'm not getting anything to the breaker from the gen head.

Thanks DEPENDABLE for the manual, looks like I will try flashing the field as shown in the manual.

I'll update with my success/failure!

Chris

 

[bchauvette]

Did you pull the engine throttle all the way out and adjust the frequency to 60 cycles with the vernier throttle ? The vernier throttle is the black knob below the dash with the red button. My truck runs with it always out. You slightly adjust the rpm by turning the knob and looking at the frequency gauge on the power panel until the little 60 cycle thingy vibrates the most. You need long arms or two people. Actually when I do this I find the voltage to be low. So I adjust to voltage.

BTW posted this just after your first post and it disappeared?

 

[Valleyordnance]

Did you pull the engine throttle all the way out and adjust the frequency to 60 cycles with the vernier throttle ? The vernier throttle is the black knob below the dash with the red button. My truck runs with it always out. You slightly adjust the rpm by turning the knob and looking at the frequency gauge on the power panel until the little 60 cycle thingy vibrates the most. You need long arms or two people. Actually when I do this I find the voltage to be low. So I adjust to voltage.

BTW posted this just after your first post and it disappeared?

Yeah, I understand how that is supposed to work, but until I actually get ANY power from the gen head to the panel it won't help me. But thanks for the tip!

The new panel does not allow any voltage adjustment like the old set does. You get the Freq right and it should give you the 208 3 phase. (to the best of my understanding of the system)

The problem I'm having is that the gen head doesn't put out ANY voltage

Chris

 

[bchauvette]

I don't get any power until the rpm's are up. I.e. shaft turning but engine idling, transmission not in drive=no power.

 

[Sephirothq]

IF you end up needing any of those parts let me know i tore one of thos apart this past summer and saved the control box and generator/ motor.

 

[Valleyordnance]

I don't get any power until the rpm's are up. I.e. shaft turning but engine idling, transmission not in drive=no power.

Can you elaborate? I have the PTO Engaged, Transfercase in Nuetral, Engine running full throttle with hand control. Vernier throttle in (I know you use this to adjust freq) Trans in High range, just like the placard says. Truck engine is running about 1300 RPM, There is a speed increase from the jackshaft to the gen head of about 2:3 (guestimate) via belt drive to the gen head. Gen head is running about 1800 RPM (trying to get an optical tach from a buddy to check RPM)

All that and I get NO output on any of the gen head lines to the panel. Either phase/phase or phase/gnd. (I have a ground rod pounded and the chassis bonded - not sure if this is necessary).

Let me know if I missed anything.

Chris

 

[bchauvette]

This is how my gen works;

1) transmission in drive (highest selectable gear) and warmed up. listen for the transmission to shift up as rpm goes up.The PTO is driven after the transmission.

2) Vernier throttle out

3) engine throttle out

I get no output at the outlet unless the Generator rpm is close.

 

[Valleyordnance]

This is how my gen works;

1) transmission in drive (highest selectable gear) and warmed up. listen for the transmission to shift up as rpm goes up.The PTO is driven after the transmission.

2) Vernier throttle out

3) engine throttle out

I get no output at the outlet unless the Generator rpm is close.

If I pull the Vernier throttle out it runs for a minute and then kills the truck. I see where you are coming from though. I will get the tach from my buddy and check the RPM on the genhead before diving into flashing the field or pulling it to check diodes etc.

Thanks for the input guys!

I will report back with some pics if I get her running this weekend.

Chris in Phoenix

 

[auctionaddict]

Mine has to be around 2000-2100 rpms or no output.

 

[Valleyordnance]

Mine has to be around 2000-2100 rpms or no output.

On the Tach on the instrument panel? Or actual RPM at the gen head?

Chris

 

[auctionaddict]

On the Tach on the instrument panel? Or actual RPM at the gen head?

Chris

Tach in the dash..

 

[auctionaddict]

Here is a pic of what was posted in my truck...

 

[Valleyordnance]

Thanks,

Just got it running, It was not up to speed, the govner control (vernier throttle) has been dinked with and was not adjusted correctly. Checked the RPM on the Gen head at 1800 and the lights came on!

Thanks to everyone who has replied to this thread, you've all been a big help!

Chris in Phoenix

 

[bchauvette]

My "governor control" is always out. The rpms are limited and I can't get over 35 mph while driving if pushed in. At some point something limits the rpm when you pull the throttle out. I fine adjust by rotating the governor knob. If I adjust to 60 cycles my voltage is too low. I adjust to voltage.

Do you have a specific use for the generator? I'd sure hate to have that NHC250 cranking at 2,000 rpm all night using the gen set as a standby generator.

 

[ed_watts]

Generator at 1800 RPM is only 30 Hz. Until frequency is close to 60 Hz, there will be no output.

Zombie thread.

Sorry.

 

[rustystud]

Generator at 1800 RPM is only 30 Hz. Until frequency is close to 60 Hz, there will be no output.

Zombie thread.

Sorry.

No, there are a lot of generators that run at 1800 rpm. In fact the larger generators run at 900 rpm. So to get 60Hz you need either 900 rpms, 1800 rpms or 3600 rpms. See the pattern here ?

 

[ed_watts]

No, there are a lot of generators that run at 1800 rpm. In fact the larger generators run at 900 rpm. So to get 60Hz you need either 900 rpms, 1800 rpms or 3600 rpms. See the pattern here ?

Uhh...
...Yeah. I have a math degree; it all depends upon the number of poles in the generator design. I believe that the "larger" generators have thirty poles per phase and run at 120 RPM on 60-Hz systems. In this application, though, I recall having to bring my engine nearly up to redline (2300 RPM) before there was any output. Never measured generator RPM, but 60 Hz was pretty elusive until things were screaming.