MEP003A Regulator Problem

[rogerpeterson]

My MEP003A will work when I flash the field with -12VDC on TB3-5 and +12VDC pm TB3-6. I have two extra regulator boards and have tried both of them with no success.
When I measure the voltage on the reg board terminal 12 and 18 during starting, both show +24 volts. It drops to 0 when I release the start switch. Diode CR2 is good.
While starting, the freq meter goes to 60 HZ and then right back down to the low peg. When checking freq at the plug, I show 60 hz on my Fluke meter.
Sure would appreciate any help as this is my power source for the cabin in Canada.

Rog

 

[PeterD]

After you flash with the 12 volts, does it continue to work after removing the 12 volts, or drop back to zero? (I wasn't quite sure from your post...)

 

[rogerpeterson]

If I remember correctly, it dropped back to 0

 

[rogerpeterson]

I am wrong about that, we never tried removing the 12 volts and reconnecting the other leads while running. Didn't want to make the situation worse than it already was.
I had been using the generator to power a Lincoln Cracker Box welder and had done about 3 hr of welding with it, when one time we started it and it did not produce power. Had been running it on 240 volt 1 phase.

 

[rogerpeterson]

Just went out and checked the rotating rectifier diodes and they are all bad. Now to find the part #'s and get some coming.
thanks

 

[rogerpeterson]

Looking for part numbers
Looked at TM-5-6115-585-12
Looked at TM-5-6115-585-24P
Looked at TM-5-6115-585-34
None of the above gave me the part numbers. Anyone know where else to look.

 

[Speddmon]

I don't know which TM's you have but my -24 TM has them listed plain as the nose on your face...LOL

Figure 26 of the -24 TM, Item #'s 27 and 28

#27 NSN...5961-01-050-7048...Semiconductor Device, Diode

#28 NSN...5961-01-054-4151...Semiconductor Device, Diode

I can't seem to find a good cross for the NSN, but if you open the generator portion and remove the diodes, there should be a part number on the diode itself....they aren't all that special.

 

[Isaac-1]

Once you find a part number I suggest checking to see if Mouser stocks them since your in Texas it should get to you in a day or so regular ground shipping.

Ike

p.s. it will likely be a military grade diode which may cost a lot, you can usually get standard grade ones for a fraction of the price and they work the same, just not certified to as high of standard.

 

[steelandcanvas]

Hey Roger, Did you try these Guys?
Delk's Army Navy Surplus_Home

 

[rogerpeterson]

I just pulled a Rectifier out of the generator and could read 1N120 and could not read the last digit. So I ordered 3 1N1206A and 3 1N1206RA diodes.
Thanks for the help guys Really appreciate it

Rog

 

[rogerpeterson]

I just pulled a Rectifier out of the generator and could read 1N120 and could not read the last digit. So I ordered 3 1N1206A and 3 1N1206RA diodes.
Thanks for the help guys Really appreciate it

Rog

 

[Speddmon]

Good luck on your project and keep us informed on the progress.

Also, before a mod or somebody else sees and complains to you, add your location to your profile...something more than United States. It is in the rules of the site.

 

[rogerpeterson]

Thanks for the info. I had got so involved fixing the Genset that I didn't finish everything.
Will keep you posted on the outcome.

 

[LuckyDog]

Just a little more information:

Figure 26 of the -24 TM, Item #'s 27 and 28

#27 NSN...5961-01-050-7048...Semiconductor Device, Diode

#28 NSN...5961-01-054-4151...Semiconductor Device, Diode

Cross Reference:
#27 NSN...5961-01-050-7048... 1N1204RA Semiconductor Device, Diode

#28 NSN...5961-01-054-4151... 1N1204A Semiconductor Device, Diode

For future Reference: http://www.datasheetcatalog.org/datasheet/microsemi/coe-3.pdf

The 1N1206 is a 600V peak inverse voltage (piv) diode, the 1n1204 is 400 piv; so the 1206 is fine.

The R stands for reverse polarity.

 

[Speddmon]

Just a little more information:



Cross Reference:
#27 NSN...5961-01-050-7048... 1N1204RA Semiconductor Device, Diode

#28 NSN...5961-01-054-4151... 1N1204A Semiconductor Device, Diode

For future Reference: http://www.datasheetcatalog.org/datasheet/microsemi/coe-3.pdf

The 1N1206 is a 600V peak inverse voltage (piv) diode, the 1n1204 is 400 piv; so the 1206 is fine.

The R stands for reverse polarity.

Great job with the cross reference, those part numbers would make a GREAT addition to the WIKI !!!!!!!!

 

[derf]

Did you check the diodes out of the circuits? It is odd that all diodes in a stack would be bad. Maybe a single or pairs will be bad, but not all.
OTOH, if you have a bad one it is a good idea to replace all with new, and maybe higher rated diodes.