Dual Field Alternator - Moparts Forums

Register Log In Moparts Forums Moparts Question and Answer Dual Field Alternator

Print Thread

Dual Field Alternator #1429855 05/03/13 09:34 PM 05/03/13 09:34 PM
Joined: Mar 2011 Posts: 183 Charleston, SC B bronco9588 OP member
bronco9588 OP member B Joined: Mar 2011 Posts: 183 Charleston, SC	How does the Chrysler Dual Field Alternator work? What causes it to "turn off"/ "turn on" and go to full load? The story behind this is that Mancini Racing sold me a "three-wire" alternator that is not a three wire alternator. I am very displeased with them and will not be doing business with them again. I am putting in a new wiring harness and need to make sure that I wire this guy correctly. Thanks. '73 Charger Petty Blue, Black Vinyl, and Gill Slits 727 torque-flight 400 BB Chrysler 8 3/4 rear

Re: Dual Field Alternator [Re: bronco9588] #1429856 05/03/13 09:42 PM 05/03/13 09:42 PM
Joined: Jan 2007 Posts: 7,664 IN A ahy master
ahy master A Joined: Jan 2007 Posts: 7,664 IN	On the alternator, have you requested exchange? I've dealt with Mancini a good bit and they handled a little "oops" promptly and correctly for me. The alternator should have a post for the charge wire and two spade terminals for the wires that energize it and control output. The link from the archives shows the layout. http://www.moparts.org/Tech/Archive/elec/21.html

Re: Dual Field Alternator [Re: bronco9588] #1429857 05/03/13 09:56 PM 05/03/13 09:56 PM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	Quote: I am putting in a new wiring harness and need to make sure that I wire this guy correctly. Thanks. What make/year vehicle & how many terminals are on the the purchased alt? (1 large/2 small or 1 large/1 small)? live every 24 hour block of time like it's your last day on earth

Re: Dual Field Alternator [Re: RapidRobert] #1429858 05/03/13 11:50 PM 05/03/13 11:50 PM
Joined: Mar 2011 Posts: 183 Charleston, SC B bronco9588 OP member
bronco9588 OP member B Joined: Mar 2011 Posts: 183 Charleston, SC	73 charger... one large and two small. Are the two smalls identical? '73 Charger Petty Blue, Black Vinyl, and Gill Slits 727 torque-flight 400 BB Chrysler 8 3/4 rear

Re: Dual Field Alternator [Re: bronco9588] #1429859 05/04/13 12:19 AM 05/04/13 12:19 AM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	Quote: 73 charger... one large and two small. Are the two smalls identical? Yes, the 2 blue and green field wires can go on either alt male field terminal. Could you clarify more on what's the problem live every 24 hour block of time like it's your last day on earth

Re: Dual Field Alternator [Re: bronco9588] #1429860 05/04/13 12:33 AM 05/04/13 12:33 AM
Joined: Dec 2007 Posts: 18,157 Mass DAYCLONA I Live Here
DAYCLONA I Live Here Joined: Dec 2007 Posts: 18,157 Mass	Where Member 68HemiB when you need him,...this post is right up his alley, he's the authority on "dual field" alts

Re: Dual Field Alternator [Re: DAYCLONA] #1429861 05/04/13 08:50 AM 05/04/13 08:50 AM
Joined: Jan 2003 Posts: 17,861 albany ny 0 05dakota I Live Here
05dakota I Live Here 0 Joined: Jan 2003 Posts: 17,861 albany ny	what is a none 3 wire alternator?

Re: Dual Field Alternator [Re: bronco9588] #1429862 05/04/13 09:06 AM 05/04/13 09:06 AM
Joined: Jan 2003 Posts: 21,067 Niles , Ohio T therocks oh wait.but hey.lets see.oh yeah.
therocks oh wait.but hey.lets see.oh yeah. T Joined: Jan 2003 Posts: 21,067 Niles , Ohio	The regulator turns the Alt on and off.Battery charge and temp makes the demand of how much of a charge it puts out.73 would be a dual field alt.If you told them you wanted one for a 73 thats what it would be.The fields are basically the same.Rocky Chrysler Firepower

Re: Dual Field Alternator [Re: therocks] #1429863 05/04/13 10:41 AM 05/04/13 10:41 AM
Joined: Aug 2009 Posts: 1,317 Ohio J jlatessa pro stock
jlatessa pro stock J Joined: Aug 2009 Posts: 1,317 Ohio	On the same thread, does it really make any difference if your alternator puts out 15 volts unregulated? When I had it checked, the store said "that's too high". I thought the regulator determines the voltage going to your system. Thanks, Joe

Re: Dual Field Alternator [Re: bronco9588] #1429864 05/04/13 02:34 PM 05/04/13 02:34 PM
Joined: Jan 2003 Posts: 25,777 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,777 Rio Linda, CA	Quote: How does the Chrysler Dual Field Alternator work? What causes it to "turn off"/ "turn on" and go to full load? Battery voltage is applied to one field terminal on the alternator (usually a blue wire), the regulator supplies a variable ground to the second field terminal via a wire (usually green). The regulator senses the system voltage through the blue wire and adjusts the voltage by varying the ground in the green wire. The only time the alternator will put out maximum voltage is if the battery is dead or there is a fault in the system, normally the output is in the 14V range. The INTERNET, the MISinformation superhighway

Re: Dual Field Alternator [Re: John_Kunkel] #1429865 05/04/13 04:56 PM 05/04/13 04:56 PM
Joined: Mar 2011 Posts: 183 Charleston, SC B bronco9588 OP member
bronco9588 OP member B Joined: Mar 2011 Posts: 183 Charleston, SC	So "on" would be 12volts, "off" would be nothing, and full load would be 0 volts on the sensing wire? Thanks. '73 Charger Petty Blue, Black Vinyl, and Gill Slits 727 torque-flight 400 BB Chrysler 8 3/4 rear

Re: Dual Field Alternator [Re: bronco9588] #1429866 05/04/13 06:46 PM 05/04/13 06:46 PM
Joined: Jan 2003 Posts: 25,777 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,777 Rio Linda, CA	There is no "on" or "off", the alternator always tries to put out more than battery voltage. The blue wire will always have battery voltage when the key is in the RUN position. What we refer to as a 12V system is actually a 14V system (I'll probably get some disagreement here) but all of the components in a 12V system are built to handle 14V+. The INTERNET, the MISinformation superhighway

Re: Dual Field Alternator [Re: John_Kunkel] #1429867 05/04/13 07:59 PM 05/04/13 07:59 PM
Joined: Mar 2011 Posts: 183 Charleston, SC B bronco9588 OP member
bronco9588 OP member B Joined: Mar 2011 Posts: 183 Charleston, SC	So i purchased a wiring harness from rebel wiring. Anyways, the harness has a "alternator excitor" wire. I am assuming this supplies 12 volts (or 14) when the accessory bus is energied I.e. when the ignition is in run. I didn't want to damage anything as the voltage regulator would only sense 12 volts once the key is off start. It would "see" no volts until I let go of the key. Is this an issue? '73 Charger Petty Blue, Black Vinyl, and Gill Slits 727 torque-flight 400 BB Chrysler 8 3/4 rear

Re: Dual Field Alternator [Re: John_Kunkel] #1429868 05/05/13 09:21 AM 05/05/13 09:21 AM
Joined: Mar 2011 Posts: 183 Charleston, SC B bronco9588 OP member
bronco9588 OP member B Joined: Mar 2011 Posts: 183 Charleston, SC	Quote: There is no "on" or "off", the alternator always tries to put out more than battery voltage. The blue wire will always have battery voltage when the key is in the RUN position. What we refer to as a 12V system is actually a 14V system (I'll probably get some disagreement here) but all of the components in a 12V system are built to handle 14V+. I'm pretty sure the regulator uses pulse width modulation to work... under your logic, if the alternator ever saw ground it would go to max current to try to get back to 14 volts. If it sees 14 volts it would reduce ampacity. What happens if it sees nothing... I.e. the wire is disconnected? '73 Charger Petty Blue, Black Vinyl, and Gill Slits 727 torque-flight 400 BB Chrysler 8 3/4 rear

Re: Dual Field Alternator [Re: bronco9588] #1429869 05/05/13 03:16 PM 05/05/13 03:16 PM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	Quote: So i purchased a wiring harness from rebel wiring. If your harness has a blue and a green field wire(s) with the female connectors plug them into both of the alt field terminals in either order & you're set. If that harness only has a green field wire (pre '70 harness) then plug it into either alt field terminal & ground the other alt field terminal to the alt case & with the large black charge wire with the ring terminal connected to the alt "batt" stud you are all set live every 24 hour block of time like it's your last day on earth

Re: Dual Field Alternator [Re: bronco9588] #1429870 05/05/13 05:11 PM 05/05/13 05:11 PM
Joined: Jan 2003 Posts: 25,777 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,777 Rio Linda, CA	The Rebel Wiring harness is pretty much the same as the factory except for ther wire colors. The "alternator exciter" wire is probably the same as the factory blue wire...it is powered only when the switch is in the RUN position; the "accessory bus" (?) plays no part in the charging system. The INTERNET, the MISinformation superhighway

Re: Dual Field Alternator [Re: bronco9588] #1429871 05/05/13 05:12 PM 05/05/13 05:12 PM
Joined: Jan 2003 Posts: 25,777 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,777 Rio Linda, CA	Quote: I'm pretty sure the regulator uses pulse width modulation to work... under your logic, if the alternator ever saw ground it would go to max current to try to get back to 14 volts. If the green wire is grounded, the regulator becomes ineffective and the alternator goes to maximum output which usually exceeds 15V. This is an all too common fault because the green wire usually runs along the valve cover where heat sometimes deteriorates the insulation and the wire goes to ground. Quote: If it sees 14 volts it would reduce ampacity. What happens if it sees nothing... I.e. the wire is disconnected? If either field wire is disconnected there is no output from the alternator...the system reverts to battery voltage. The INTERNET, the MISinformation superhighway

Re: Dual Field Alternator [Re: John_Kunkel] #1429872 05/05/13 09:27 PM 05/05/13 09:27 PM
Joined: Mar 2011 Posts: 183 Charleston, SC B bronco9588 OP member
bronco9588 OP member B Joined: Mar 2011 Posts: 183 Charleston, SC	Quote: The Rebel Wiring harness is pretty much the same as the factory except for ther wire colors. The "alternator exciter" wire is probably the same as the factory blue wire...it is powered only when the switch is in the RUN position; the "accessory bus" (?) plays no part in the charging system. The harness is made up of 4 fuse boxes with 4 fuses each. Each "high" side of the fuse boxes are tied together and share the same voltage source. Two of the 4 fuse boxes are always on, one is on the start bus, and the last is triggered on "accessory" (which is on when the engine is running). The alternator exciter wire is located on accessory. Why, I don't know, but I don't think it matters much in this case. Might mean that I drain the battery if I am just listening to the radio or something? '73 Charger Petty Blue, Black Vinyl, and Gill Slits 727 torque-flight 400 BB Chrysler 8 3/4 rear

Re: Dual Field Alternator [Re: bronco9588] #1429873 05/05/13 10:21 PM 05/05/13 10:21 PM
Joined: Jun 2008 Posts: 1,822 Colorado D denfireguy top fuel
denfireguy top fuel D Joined: Jun 2008 Posts: 1,822 Colorado	Quote: Quote: There is no "on" or "off", the alternator always tries to put out more than battery voltage. The blue wire will always have battery voltage when the key is in the RUN position. What we refer to as a 12V system is actually a 14V system (I'll probably get some disagreement here) but all of the components in a 12V system are built to handle 14V+. I'm pretty sure the regulator uses pulse width modulation to work... under your logic, if the alternator ever saw ground it would go to max current to try to get back to 14 volts. If it sees 14 volts it would reduce ampacity. What happens if it sees nothing... I.e. the wire is disconnected? Mopar alternators with electronic regulators did not employ pulse width modulation. Rather, the battery voltage through the ignition switch was fed to one terminal. The other terminal is connected to the diamond shape pass transistor on the regulator. It operates in linear mode. The output to the field wire can vary from about ten volts down to .7 volts. At .7 volts, the transistor is in full conduction. The .7 of a volt is the result of the junction voltage typical of a silicon transistor and that is as close to zero as it till get and the full battery voltage less distributed wire resistive loss and junction loss will appear across the field and maximum output is achieved. Pulse width modulation works with square waves and generates massive amounts of electrical noise that would render that era's AM radios pretty unusable. I doubt Chrysler engineers even considered it. Craig 2014 Ram 1500 Laramie, 73 Cuda Previous mopars: 62 Valiant, 65 Fury III, 68 Fury III, 72 Satellite, 74 Satellite, 89 Acclaim, 98 Caravan, 2003 Durango Only previous Non-Mopar: Schwinn Tornado

Re: Dual Field Alternator [Re: DAYCLONA] #1429874 05/06/13 12:54 PM 05/06/13 12:54 PM
Joined: Nov 2004 Posts: 9,312 SoCal 68HemiB master
68HemiB master Joined: Nov 2004 Posts: 9,312 SoCal	Quote: Where Member 68HemiB when you need him,...this post is right up his alley, he's the authority on "dual field" alts Down to just a blue car now.

Moderated by Al_Alguire, Hotwheelsjr, moparts, not_a_charger, RangerDan440, tboomer

Hop To

Powered by UBB.threads™ PHP Forum Software 7.7.1