Alternater Hookup

[Ericbsc]

I have replaced the 200 lb monster generator in my 05 eagle with a Leece Neville 270 amp alternator. It was new equipment fore firetrucks. I need a little help!! I have the ground to the frame of the bus and the positive back to the post where the two 8-d's are. I started the bus and let run for app. 5-10 min. Charge is good at 14 9vdc. I turned the bus off and went back to inspect. When I touched the alternator is was very hot. 2-3 sec. and you got very warm!! Is this normal? The bus batteries are less than 8months old. I charged the recently as I have used the radio for several days while working.

[NJT 5573]

Eric,

14.9 seems a little high to me. I think you should talk to the pros. Get the Model # and Serial # from your unit and go to prestolite.com, click on support and give them your info. They will get right back to you online and will follow up with a phone consult for no charge if needed. Look for a regulator # to give them also.

The last unit I had that made heat, burned the + and - connection bolts right off the unit, so I think you need to talk with the guys that made it.

(Motorola, Leece Neville and Prestolite are all the same). Are you sure you don't have a 8SC model somewhere in the 150-175 amp range? Did you get a 24 volt unit by mistake? Give me some numbers.

If you have the JB series, you must have a 4867JB with a 102835 regulator. The 100650 regulator is a 12 volt trigger regulator that is made for stand alone service, (no batterys). If this unit ran a pump or something it probably just needs a regulator change. The regulators cost between $57 and $120 depending on where you buy them. If you have one of the other alternator numbers, 4870JB, 4871JB, or 4874JB you will need to talk to the shop, but its probable that the 102835 will work with all these units since they are all 12 volt and clockwise so the stators and rotor should be 12 V and 12 V.

[Ericbsc]

What I have is p/n A0014864JB. 14vdc, 270 amps. The website says 12vdc, but it is on the label 14vdc!! Thats odd. I talked to the guy there today because the website also says clockwise rotation. He checked and said it would work either direction. I left a message about the heat but did not hear back today. I bought this unit from a guy who bought out a warehouse. I ran it tonight for about 15 min on high idle. The only part that seems to get hot is the center mag field. the ends which are alum are cool. I guess I checked it earlier after I shut down and the alum absorbed heat. I am assuming with a built in rectifier that I would not need a regulator? Any ideas.

[Sojourner]

About alternator operation temperature....air cool version will get too hot to touch at about 30% of full output. However a open diode will cause it be hotter still...270°F.
Normal load continuous operating temperature is around 165°F.
Take IR gun reading and report its temperature to us.

If you will post a photo of alternator's fan & pulley. This will determine the proper direction.

All in all...the air cool alternator is sensitive to operating temperature. The hotter it gets the less effective charging rate. They not as heavy duty as water or oil cool alternator for continuous high limit current service.

FWIW

Sojourn for Christ, Gerald

[Len Silva]

Those alternators will operate in either direction but need the correct fan for the direction you are using.  There are some universal fans but I don't think they will operate as well.

[Ericbsc]

This is the best I can get in the dark. The big flash reflects off the siding to bad. Cant find my temp probe for the meter but by the rule of touch 3-5 seconds should be in the 250-175 range. If that is the case I may be alright. That 14vdc may be a problem, don't know yet. Everything including radio b-up camera works fine.

[Ericbsc]

This one has straight fins. Bidirectional.

[NJT 5573]

Eric,

What I see with your 4864 JB is possibly an internal regulator, (hard to get a regulator part number with out disassembly) and the 14 volt issue. Normally 13.6 is about all you want on 12 volt batterys.

The 14 volt build code relates to fire equiptment and may/will boil the water out of your batterys. The JB accepts both external and internal regulators from what I see, so I believe you can just disassemble the case and remove the 14 volt regulator and install a new 12 volt unit either externally or internally, probably depending on regulator cost. The 102835 should be the right regulator for you, but prestolite.com won't lead you astray and I might! They can also tell you the build regulator being used from the 4864 JB code and I can't find that code.

Some things to think about, are how did they get 14 volts? Is it a 12 V rotor and 12 V stator with a 14 V regulator? Is it a 7V rotor with a 14 volt stator, 14 V rotor, 14 V stator? Maybe a 12 V regulator will not help?

24 volt Prestolite Alternators are made with both 12 V and 24 V rotors and the stators are different to provide 24V output, so you need more info. My guess is you may have a unit setup (14 volt trigger, off, on), for a stand alone pump operation running around 15 V that is not compatable with a battery setup. If you have a 12V stator and a 12V rotor I think you can just put on the correct self exciting regulator, 102835.

[NJT 5573]

Eric, what are the numbers below the red paint in the picture?

[Ericbsc]

That is the p/n A0014864Jb sales no 4864JB

[NJT 5573]

OK, I was hoping for a regulator number.

[rv_safetyman]

The rule of thumb for holding your hand on a hot part may be a bit high.  My experienc (with quite a bit of testing to back it up) is that the normal person can leave their hand on something that is 140 degrees for a few seconds and may feel uncomfortable.  When you start trying to go to higher temperatures, the relationship gets a bit cloudy.  Part of the issue is the amount of moisture on your skin.  I don't think you could leave your had on a part that is 165 * for even a couple of seconds.  

Guess that all suggests that you need to find someone with an infra-red temperature device.  They are sensitive to emissivity, so try to aim it at a dark/black part of the alternator if possible.  

Since your alternator is going "backwards" from the norm, I would bet that the fan needs to be replaced.  Having said that, I have seen many with blades that strictly radial (no fan blade shape).  If you can find one with a fan type blade for the correct direction, you will be better off.

Jim

[Ericbsc]

Found the temp probe. Surface temp on field coil area (center) is 129 F. after app 10 min hi idle. Temp on ends is 97-102. Not as hot as I thought.

[Sojourner]

This one has straight fins. Bidirectional.

Your right....that what it shows in the photo...fan's fins is straight line from the center of the shaft mean bidirectional.

Thank you for the photo.

Sojourn for Christ, Gerald