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Question on GM Delco-Remy 10SI alternator


240zprace

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the guy said if i go with a single wire set up on the GM alternator, i don,t have to do anything to the plug that hooks up into the xternal regulator,just leave it alone. .my car is a 72 240. now,i know if i use an internal alternator from a later 280zx i have to jump some of the wires that hooks up into the xternal vol.regulator. is what the guy saying true?

that i don't need to jump any of the wires that hook up to xternal regulator

if i go with the single wire internal regulator alternator (GM Delco10si).

please reply to whom has done this conversion or have any knowledge about it. THANKS

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I too am planning on using a 10si alternator. I did some studying up on the one wire. It sounds so good, but there is a drawback. It is setup to turn on at a certain RPM, where as the traditional ignition operated is on from the word go. What worried me is they were claiming it would kick on at something like 2K or 2500 rpm's. If your running any type of underdrive pulley, it would, of course kick on later.

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I had a one wire SI on a farm tractor. They don't turn real high RPM but the pulley may have been setup to spin the alternator faster. I also have one on a 55 Ford and it appears to have a standard alternator pulley. Neither of these ever gave me any problems but I have also heard that they don't "turn on " at lower rpm's it just never gave me any trouble.

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From the Powermaster website....

 

http://www.powermastermotorsports.com

 

"A one wire alternator has a turn on point (sometimes called “cut inâ€, which is typically 1200 engine RPM’s). This is the speed where the internal sense circuitry connects the battery to the voltage regulator, thereby turning the alternator on. Once the voltage regulator turns on, the alternator will remain on and charging until the engine comes to a complete stop. If the engine idle speed and pulley ratio combination do not allow the alternator to come up to this point during starting, the engine will have to be revved up to turn the one wire alternator on. The sense circuitry in the one-wire regulator can be bypassed to excite the alternator as soon as the ignition switch is turned on. This is called three-wire operation. This means the alternator will not be dependent on reaching a certain turn on RPM.

"

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Thanks jgkurz because that's an excellent article. I will also add that the internal regulator in the Delco is identical except, as noted, it is excited "turned on" internally instead of externally through a wire from the battery. Usually fast idle from a freshly started engine is enough to turn it on.

 

You will however, need a second wire if you want a warning light.

 

Fortunately the statement “The 1-wire sounds easy, but I hear the original 3-wire may provide better voltage regulation†isn’t true.

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  • 3 years later...
Thanks jgkurz because that's an excellent article. I will also add that the internal regulator in the Delco is identical except, as noted, it is excited "turned on" internally instead of externally through a wire from the battery. Usually fast idle from a freshly started engine is enough to turn it on.

 

You will however, need a second wire if you want a warning light.

 

Fortunately the statement “The 1-wire sounds easy, but I hear the original 3-wire may provide better voltage regulation” isn’t true.

 

 

This is an old thread but I thought I provide some information I learned recently. I did install a Powermaster 140amp 10SI alternator as discussed above. It's done mostly what I needed except for the fact that the L28 pulley system doesn't turn a Chevy alternator fast at idle enough to provide enough voltage. At 750RPM I get about 12.5V. At 1000RPM (much to high for idle) I get about 15V. Unfortunately this causes a severe battery drain if I'm driving in city traffic. Although my Powermaster was suppose to be a 1-wire unit capable of 3-wire, it really is only a 1-wire. If a 1-wire "self exciting" regulator is wired up in a 3-wire configuration it does permit a warning light but it does NOT allow connection of the "remote sensing" wire that an OEM 3-wire regulator allows. In case you don't know, the "remote sensing" ability of a true 3-wire GM alternator allows the regulator to sense loads on the electrical system if connected to a junction not on the actual battery. For this reason I stand by my statement that a 3-wire alternator will regulate voltage better than a 1-wire of similar amperage. My plan is to remove my 1-wire regulator and install a 3-wire regulator into my Powermaster 10SI. The part cost me $3.00. Another cool feature of a 3-wire is the ability to add a potentiometer to the remote sense wire so you can raise the output voltage to desired levels by adding resistance to the wire. One more thing. This is potentially dangerous and could damage your wiring or battery if voltage is increased to over 15.5v. Below is a website that goes into this with more detail.

 

http://www.madelectrical.com/electricaltech/remotevoltagesensing.shtml

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Why isn't it true?

 

That's my point. I think it is true. The 3-wire alternators have a remote voltage sensing wire that allow them better match the electrical loads being put on the system. In other words, the purpose of the sense wire is to monitor the system voltage, and increase or decrease the charging rate, depending on the system load and/or battery condition. A 1-wire alternator cannot do this.

 

Read here:

 

http://www.madelectrical.com/electri...esensing.shtml

 

http://www.madelectrical.com/electricaltech/onewire-threewire.shtml

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