another 9N 12 volt question

racerjim0 · Nov 18, 2014

Reading that a single wire 10si alternator for a
9n will not start charging till it gets to around
1800-2000 rpm raises a question.
Does the 1800-2000 rpm refer to the engine or the
alternator?
The alternator pulley on the tractor I am working
on is around 1 5/8" diameter at the center of the
"V".
Can I calculate the engine/alternators pulley's
rpm's to determine the alternators true rpm?
I would rather run a single wire setup if it is
going to charge at normal engine operating rpm's.
I had bought a 197 lamped indicator light but it
uses the mounting bolt for the ground so it won't
really work the way I had intended.
Simple is better here I think.

TheOldHokie · Nov 18, 2014

(quoted from post at 10:11:24 11/18/14) Reading that a single wire 10si alternator for a
9n will not start charging till it gets to around
1800-2000 rpm raises a question.
Does the 1800-2000 rpm refer to the engine or the
alternator?
The alternator pulley on the tractor I am working
on is around 1 5/8" diameter at the center of the
"V".
Can I calculate the engine/alternators pulley's
rpm's to determine the alternators true rpm?
I would rather run a single wire setup if it is
going to charge at normal engine operating rpm's.
I had bought a 197 lamped indicator light but it
uses the mounting bolt for the ground so it won't
really work the way I had intended.
Simple is better here I think.

Yes.

Alternator RPM = (Crankshaft pulley diameter / alternator pulley diameter) x Engine RPM

(n.b. JMOR got me again - I originally had the pulley ratio inverted

)

That said there are LOTS of 10Si's working just fine on N-series tractors. You just need to get the proper size pulley for the alternator and 1.5" is not going to get you 1800 RPM on the 10Si.

TOH

lha · Nov 18, 2014

A 1157 bulb,wired inline,and a diode to keep the battery from draining will make the alternator work better. Someone who has done this can speak better about it than I can,mine's 6v+g. lha

kylemorley · Nov 18, 2014

I've done several from-scratch 12V conversion all which have worked out fine. I don't like single wire because of the output issues. With a 3 wire I just use any pulley that happens to look roughly the right size, and it always seems to work out just fine.

The other thing about single wire is that Delco has, I am told, never made a single wire alternator - the single wire alternators are all modified rebuilds or modified copies of the Delco by other, asian, manufacturers. Which means you cannot run down to Advance and get a $35 replacement when your alternator fails. Take the minutes it takes to hook up the 2 extra wires and you will have better performance, and cheaper alternators.

HCooke · Nov 18, 2014

"Reading that a single wire 10si alternator for a 9n will not start charging till it gets to around 1800-2000 rpm raises a question."

A myth - I have a 1 wire alternator purchase from YT that begins charging immediately. Not all 10si alternators are the same.

Royse · Nov 18, 2014

On your other post I mentioned that my one wire has to be
revved up more than my three wires before it starts charging,
but my engine does not have to be anywhere near 1800 RPMs.
More like 900 - 1000 RPMs in my case. I do not know what the
pulley ratio is on mine though.
YT sells the 5/8 inch wide pulley if you need one.
I still like the three wire better! LOL

tractorguy2 · Nov 18, 2014

The only difference between a delco one wire and a
three wire is the regulator is self exciting.

If you pop that rubber plug out on the regulator
on the one wire. you will see the two terminals
for the two wires.

I have converted one wires over to three by just
hooking up the two terminals on the regulator.

Jim in Eastern North Caro · Nov 18, 2014

I don't know how much resistance an alternator puts on an engine while starting, though I expect it is much less than the resistance when you do not depress the clutch. And much less when you don't depress the clutch and the PTO is on. So there are four levels of resistance that can vary when starting: 1) alternator disengaged since it could be a 1-wire and not be putting back pressure on the engine, 2) clutch in and all gears disengaged, 3) clutch out and PTO off, and 4) clutch out and PTO on. I have a 1-wire and purposely did not do the diode or jumper so that the engine has virtually no strain when starting, (I start with depressing the clutch), but after it is running smoothly, I add enough RPM's to engage the alternator. Works for me. In an airplane I once had, the checklist had the starting sequence with the alternator switch in the off position, and after starting and running smoothly, you could turn the alternator switch on and it would lose about 50 rpms, so there is some resistance there.

souNdguy · Nov 18, 2014

self excite rpm will vary based on what vreg IC was used. you CAN get low turn on vregs, though they usually cost more.. ( but then many of these 1 wire kits are expensive.. so maybee they are using a loewer rpm vreg?... regular 3 wire alt can be had as low as 29$ with core. and 45$ without core. )

Your marker lamp that uses a mounting tab to ground. is it the plastic lamp base style that simly has a metal tab bent unde rthe mounting ear? it is quite easy to re-engineer the electrical connections to make it work. OR just insultate it and hide it under the dash. Alternately, use a diode.

kylemorley · Nov 18, 2014

The mechanical difference is that the 1-wire has a modified aftermarket internal regulator that makes the alternator self exciting. But since Delco does not make a 1-wire alternator, there is no standard for how a 1-wire regulator should work, so it is difficult to make any blanket statements concerning how they perform.

It is useful to know that (at least some) 1-wires can actually be wired either way, but considering that a 1-wire costs double what a 3-wire does, there isn't any good reason to do it, unless to try and improve the performance of a 1-wire that is not reliably self-exiting.

(quoted from post at 16:06:37 11/18/14) The only difference between a delco one wire and a
three wire is the regulator is self exciting.

another 9N 12 volt question

racerjim0

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TheOldHokie

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lha

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kylemorley

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HCooke

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Royse

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tractorguy2

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Jim in Eastern North Caro

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souNdguy

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kylemorley

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