Mep 804b Alternator regulator

[jmenende]

Good day folks.

Been having a hard time finding the regulator part number for the alternator on my 804b. Anyone have any leads?

Thanks

 

[LuckeyD]

I recommend you research posts Guyfang posted. He posted everything you need. Step 1; What type do you have, TRC or Libby. (TRC black or green Libby regulator). only replace with same type. Step 2: PN: 19870 is TRC, and PN: 122-3054 is Libby. This is just the regulator. DLA Avaition put together kits after countless requests from LARs that contain everything you need to change from one to the other, but no Part Number you can actually get outside the Military system. The following are different between the two: Regulator, Voltage adjust rheostat, R-16 located behind the green CKTBKR panel, and the power sensing transformer. Libby trans have black terminal boards and TRC has just connecting loop terminals. Mixed up and you will have EXPENSIVE issues.

 

[jmenende]

I recommend you research posts Guyfang posted. He posted everything you need. Step 1; What type do you have, TRC or Libby. (TRC black or green Libby regulator). only replace with same type. Step 2: PN: 19870 is TRC, and PN: 122-3054 is Libby. This is just the regulator. DLA Avaition put together kits after countless requests from LARs that contain everything you need to change from one to the other, but no Part Number you can actually get outside the Military system. The following are different between the two: Regulator, Voltage adjust rheostat, R-16 located behind the green CKTBKR panel, and the power sensing transformer. Libby trans have black terminal boards and TRC has just connecting loop terminals. Mixed up and you will have EXPENSIVE issues.

Thank you for attempting to help but im not talking about voltage regulator for the generator. My request is for the regulator on the alternator made by hitachi.

 

[LuckeyD]

OK, there was no parts they put in the Gen manual or engine manual for the Battery charging alternator regulator from Hitachi on the B model. It was a 35 AMP battery charging alternator that put out too much current popping the 30 AMP battery charging fuse or 25A breaker causing a free running battery charging alternator that burnt out the internal regulator. It sensed a continual lowering of battery voltage and thus went into 100% charge rate and over heated. Some folks took the alternator apart and took the regulator to a local car parts place. Others just replaced the alternator being careful to also change the pulley carefully and they measured the alternator shaft. Big fan on a narrow belt so keep it tight and the belt stretches. We recommended to ensure batteries were fully charged to prevent this battery charging issue. Didn't work. I attached a file. There is a lower rated amperage alternator that works.

 

[jmenende]

Thank you, this pretty much solves it.

 

[LuckeyD]

I got that multimeter at SEARS at FT Bragg. Worked for a while, but nothing beats the Fluke 112 or 175

 

[Lundy]

According to my local (Reno NV) alternator and starter rebuilder:
Hitachi no longer supports the alternator.
There are no replacement voltage regulators produced for it.
You need to replace with another mfgrs alternator.

What I found as an almost direct replacement is a Mitsubishi 12602N . It is 24volt 35amp same hook up plugs etc. The pulley offset is the same when using the inner v-belt position (it is a double v-belt pulley compared to a single on the Hitachi,.. no interference though). You will need to use a bolt, nut and washer (10mm or 3/8” diameter) for the adjustment tensioner. The pivot bolt diameter is larger so you will need to sleeve both tabs down to 10mm and reuse the Hitachi 10mm pivot bolt. I found some thin wall tubing from a water heater burner was perfect fit. Another way would be to drill out the Yanmar pivot mount,.. time consuming. This alternator is used by Yanmar for New Holland excavators so a replacement mount should also be available ,…$$$. I have 2 of my 3 803b gensets using the Mitsubishi alternators without issue. I would recommend replacing the v-belt though, as a 10year old belt has no business being used on a generator. I had one shred and clog the radiator! 3hours to clean it out!! And Very messy!