04-19-2021, 01:54 PM | #26 |
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Re: Alternator
>>"flash the field"<<
An interesting term to use when you are talking about an AC Alternator. If we were talking about a DC Generator that term would make more sense. When discussing a DC Generator, someone will always mention Polarizing the Generator. In the first image below there are Iron Pole Pieces used in DC generators, The Field Windings are wrapped around these Pole Pieces. These Iron Pole Pieces retain a great deal of magnetism. The Polarity of the magnetism retained in these pole pieces is crucial to the correct operation of a DC Generator. When working on a DC Generator, it is common for the polarity of the residual magnetism to be reversed. It is then very important to correctly align the magnetic polarity of the pole pieces, with the Polarization procedure. AC Alternators do retain some residual magnetism, but the polarity is not an issue. In the second image, the ignition switch connects 12V from the battery, through the voltage regulator, directly to the field winding. Full Field magnetism is generated and current begins to flow in the Stator Windings. This ignition circuit is called a Exciter Circuit. Full Field magnetism is generated the moment the key is turned ON and also at idle. Field magnetism is reduced by the voltage regulator, as max voltage is reached.
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'67 GMC 2500, 292, 4spd, AC |
04-19-2021, 02:20 PM | #27 |
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Re: Alternator
>>The theory behind this is a perfect wire with perfect connections will not drop voltage so the meter will read zero volts.<<
All copper wire has resistance to electrical flow. The fatter the wire, the less resistance, the lower the voltage drop from one-end-to-the-other. Chevy relies on that voltage drop on the wire between the Alt and the Battery. That is the basis of the design of the Ammeter circuit. The greater the Alternator output, the greater the Voltage Drop on that wire, the greater the Ammeter indication. The type of Ammeter used in these trucks must have an External SHUNT. In this case the Charging wire serves doubly duty and is also the Shunt Wire for the Ammeter. Other Ammeters contain an Internal Shunt. This '67-72 Chevy Ammeter does not.
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'67 GMC 2500, 292, 4spd, AC |
04-20-2021, 10:57 PM | #28 | |
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Re: Alternator
Quote:
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Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
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04-20-2021, 11:07 PM | #29 | |
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Re: Alternator
Quote:
What would you expect the voltage drop on the Shunt wire to be on a stock system at idle with all the switchable loads turned off (i.e. wipers or headlights)? Hopefully the OP will be able get things back to normal.
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Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 Last edited by HO455; 04-20-2021 at 11:34 PM. Reason: -4 Grammer |
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04-21-2021, 08:08 AM | #30 |
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Re: Alternator
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04-21-2021, 08:58 AM | #31 |
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Re: Alternator
That is good to hear. Congradulations!
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Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
04-21-2021, 12:36 PM | #32 |
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Re: Alternator
>>bumping up the idle by about 150rpm............... idling at around 850-900 rpm.<<
That's not what I would consider a solution. I wouldn't even consider 850-900 as an acceptable idle rpm. That's the rpm I would expect on the 1st or 2nd step of the High Speed idle cam mechanism. Earlier in post #16 you said you had 14.7V at cruise and 13v at idle. What is wrong with that? When you are talking about an automatic with an idle of 850-900 rpm, you probably have 150-200 rpm difference between Drive and Neutral. To me that is completely unacceptable. Having to BANG a transmission into drive, because of an incorrect idle rpm drives me crazy.
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'67 GMC 2500, 292, 4spd, AC |
04-21-2021, 01:34 PM | #33 |
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Re: Alternator
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04-21-2021, 03:15 PM | #34 |
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Re: Alternator
In post #16 you said 13V.
In post #30 you said you bumped the idle 150 up tp 850. Are you now saying your new 12SI is providing 12.3V at 700 rpm? In post #11 you provided a picture of the old 10DN alternator. What was its output voltage , at what idle rpm? Unless you have a high load at idle, it doesn't sound like the new 12SI is working properly.
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'67 GMC 2500, 292, 4spd, AC |
04-22-2021, 06:23 PM | #35 |
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Re: Alternator
Hello I think I will need this later.
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04-22-2021, 08:47 PM | #36 |
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Re: Alternator
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04-22-2021, 10:15 PM | #37 |
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Re: Alternator
That seems to be a common problem with rebuilt stuff these days. I've replaced the rebuilt alternator on my truck twice, now. Both times for bad diodes.
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04-23-2021, 07:34 AM | #38 |
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Re: Alternator
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04-23-2021, 10:51 AM | #39 |
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Re: Alternator
I would not have expected that, for sure. More and more poor quality stuff is produced, anymore.
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
04-29-2021, 07:04 AM | #40 |
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Re: Alternator
Since installing the new alternator, i am experiencing a pretty bad battery drain. is it possible that it is from the way it is wired?
I connected the 2 outside blue and brown wires at the regulator. I connected the 2 wires at the alternator plug what would be the brown and white wires (previous owner made them them the same color wires black) and connected both of them to the White wire on the ne 12si plug. I feel this might have been wrong. I ran a new 10ga wire to the battery from the the big red bolt on the back. I ran a new 10ga ground wire from the alternator housing to the ground on the battery. Last edited by Minkota; 04-29-2021 at 08:58 AM. |
04-29-2021, 09:00 AM | #41 | |
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Re: Alternator
Quote:
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04-29-2021, 11:38 AM | #42 |
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Re: Alternator
I installed a 12SI alternator a few months ago. Initially, I had the wires swapped at the alternator, and this created a battery drain. Here's how I have the wires connected now. The original voltage regulator had the following four wires connected to it:
brown red white blue I purchased a jumper that plugs into the harness in place of the voltage regulator, and it connects the following wires together: brown to blue red to white The blue and white wires then run to the alternator and connect, as follows: blue - 1 white - 2 Another way to say this is: regulator brown connects to alternator pin 1 (uses blue wire) regulator red connects to alternator pin 2 (uses white wire) Last edited by pjmoreland; 04-29-2021 at 12:15 PM. |
04-29-2021, 11:57 AM | #43 |
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Re: Alternator
I went with a 100amp one wire alt. This made things simple.
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04-29-2021, 12:14 PM | #44 |
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Re: Alternator
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04-29-2021, 04:43 PM | #45 | |
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Re: Alternator
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04-30-2021, 02:10 PM | #46 |
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Re: Alternator
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