alternator

i have a 706 that has been converted to alternator... My problem is that when i start the engine the light wont go off till i rev it up about 3rd throttle or more ... once i do that i will saty out at a idle... is there some thing i can do about that or just leave it...GM alternator.. look like from a older car or pickup.

it takes a few rpm to excite the internal regulator on those alternators and put them into charge mode. so from what i understand that is normal, but if I am wrong i am sure someone else will correct me.

thanks tjv... maybe i will just leave as it charges ok...but most vehicels go about as so as it go from crank mode to run mode... thanks again for your response.

I have a H Farmall that did the same thing, with a GM alternator. Bought a diode from Charlie Uthke, Charlie's Repair, 22195 State Hwy 56, Austin, MN 55912 [email protected], I think for only a few dollars. Totally fixed mine, charges immediately, then tapers off.

GM one wire or 3 wire? If the one wire it needs a smaller pully. The one wires needs more RPMs to excite it enough to charge on start up. Smaller pully on the alternator can fix that problem. If it's a 3 wire that should not be a problem as long as it's wired right. 3 wire should just charge on start up at idle.



Rick

There is a different regulator available that kicks in at a lower RPM. It is available at a shop that rebuilds alternators, I have had it put in most of my tractor alternators with the GM alt and it works great. Small pulleys seem to be hard to come by up this way.

Sounds like the common 1 wire set up and yep that is how they work. Better set up is the one like in the picture below which if you want to set one up is you buy an alternator made to fit a 1980 Chev pick up not power any thing no AC. Cost at an O'Reilly's is around $45 plus a core and that is one with a life time warranty to boot

Morris, if you have single wire I would just leave it and call it normal. Pain in the rear but normal. If you have the three wire, you may have a excessive high ohm resistor feeding number one wire. I prefer diodes over resistors but either work. On the diesel tractors I have changed many from a 25 ohm resistor to a 10 ohm resistor to overcome this problem. Lot of operators are not comfortable revving up a cold engine to get it charging. That would be the 66 series that came factory with the internally regulated alternator.

Hi Pete,,,you are right ... although it charges alright,I just dont like to rev up a cold engine..i have diode in line now but it dont look as large phisically as the one pictured in the post..not sure what the electrical value is..any way it is wired like the picture in the post of responses.. not sure if a resistor would be any better .what u think?

Diode should offer no resistance to 12 volt current flow. With key on , engine not running, you should have a nice bright test light with connector unhooked. Resistor would be worse. See you. Pete

With Pete's info. in mind, the key must be on and the tractor not running. With the connection to the alternator removed, the connector to the # 1 terminal should show battery volts. If it shows less, or none, the wire is disconnected, or the diode is bad. Jim

That's pretty much how the 10SI alternator works - at startup the engine's gotta be run up until the alternator shaft is spinning 2,500 RPM or so for it to "turn on" .

My Super M with the 10SI alternator needs to be run up to 1/3 governor or so to get it to start charging; so does a buddy's JD A and 4430. Back in the 80's I owned several GM vehicles that needed to be "goosed" at startup to extinguish the charge light too.

If it really bothers you there are a couple fixes:

1 - Install a smaller pulley to spin the alternator faster.

2 - Swap the alternator you've got for one with a LOWER output rating. Most aftermarket rebuilds are 55 or 61 amp. Replacing it with 37 or 42 amp unit will begin charging at noticeably lower RPM. (It sounds counterintuitive, but that's how the 10SI family behaves....)

Myself I simply live with it. After a cold start I'll let my SM idle for a minute or so. I then slowly pull the governor until the idiot light goes out then idle it back down until ready to put it to work.

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To your diode question you've probably got a 1N4004 or equivalent (it's pretty small!). But any diode rated for at least 100 PRV and 1.0 amp forward current will work.