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Re: Dual Field Alternator: Swapping the Field Wires [Re: NachoRT74] #1150435 01/06/12 12:55 PM 01/06/12 12:55 PM
Joined: Aug 2007 Posts: 6,095 Valencia, España NachoRT74 master
NachoRT74 master Joined: Aug 2007 Posts: 6,095 Valencia, España	talking about what I was told about the brush isolator melted getting stuck the brush... found a malfunction on my alt and look what I found: ( after fix this, mounted back the alt, worked great for 10 minutes and broken again... the rotor went bad. It's open. ) 7004260-lafoto(13).jpg (336 downloads) With a Charger born in Chrysler assembly plant in Valencia, Venezuela

Re: Dual Field Alternator: Swapping the Field Wires [Re: denfireguy] #1150436 01/06/12 05:34 PM 01/06/12 05:34 PM
Joined: Jan 2003 Posts: 5,443 Indiana Y YO7_A66 OP master
YO7_A66 OP master Y Joined: Jan 2003 Posts: 5,443 Indiana	""The machine applies 12 volts to the field on one wire and grounds the other. If there was a short, the logic in the tester would see that short and assume the person hooking it up did it wrong. When he reverses it, the shorted field connection is now hooked to the machines ground. The logic now sees a complete circuit with a good ground and less current draw on the 12V feed. Machine is happy, the alternator tests good. Unfortunately, because of the internal short, it will not work right in the car going to full output at all times. Powermaster is right, the alternator is bad and as I suspected, the parts store testers do not fully test dual field alternators. "" Excellent description. Thank you. I have already made arrangements with Powermaster and the alternator is going back next week for a full test and rebuild. Thank you to all. 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

Re: Dual Field Alternator: Swapping the Field Wires [Re: denfireguy] #1150437 01/07/12 06:03 PM 01/07/12 06:03 PM
Joined: Jan 2003 Posts: 5,443 Indiana Y YO7_A66 OP master
YO7_A66 OP master Y Joined: Jan 2003 Posts: 5,443 Indiana	""Unfortunately, because of the internal short, it will not work right in the car going to full output at all times."" I swapped the field wires to see if the ammeter/voltage guage changed, and as mentioned above, it acted the same with the wires swapped. The alternator is off and in a box waiting to be shipped back for repair. Thanks again to all. 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

Re: Dual Field Alternator: Swapping the Field Wires [Re: YO7_A66] #1150438 01/13/12 06:17 PM 01/13/12 06:17 PM
Joined: Oct 2010 Posts: 606 Montana Y Yancy Derringer mopar
Yancy Derringer mopar Y Joined: Oct 2010 Posts: 606 Montana	Other than a short in the field circuit, there is ONE other remote possibility. Since some of these aftermarket units may well come from (cough, gag) questionable sources, it just might be that the METALLIC ALLOY of the rotor core is not what it should be. It MIGHT just be that some units RETAIN MAGNETISM far better than they should, and that when reversing the field, the residual magnetism in the core (at least for a short time) will be "fighting" the polarity of the field due to the swapped field connections. Back in the days when rebuilders were "cheapy" modifying older frames for isolated field, I used to see a fair number that were mistakenly grounded.

Re: Dual Field Alternator: Swapping the Field Wires [Re: YO7_A66] #1150439 01/19/12 08:34 AM 01/19/12 08:34 AM
Joined: Jan 2003 Posts: 5,443 Indiana Y YO7_A66 OP master
YO7_A66 OP master Y Joined: Jan 2003 Posts: 5,443 Indiana	The alternator is currently at Powermaster and they have been testing it and they can not make it fail. Review: The test machine at NAPA told the technician to reverse the field wires to be able to complete the test. My ammeter fluctuates at idle and up to about 1500rpms, then it smooths out after 1500rpms. It did not do this until my last drive of the season. My system voltage jumps back and fourth from 13-15 volts while the ammeter is fluctuating. A new voltage regulator showed the same results. I am trying to give them all of my info so they can keep checking it but I am not sure what else to tell them before they try and send it back to me. Is there another type of voltage regulator that I can test? My current two are the NAPA brand. I do have a Chrysler BLUE (constant output) regulator that I could test if needed. Any suggestions are appreciated. 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

Re: Dual Field Alternator: Swapping the Field Wires [Re: YO7_A66] #1150440 01/19/12 10:16 AM 01/19/12 10:16 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: My ammeter fluctuates at idle and up to about 1500rpms, then it smooths out after 1500rpms. My system voltage jumps back and fourth from 13-15 volts while the ammeter is fluctuating. A new voltage regulator showed the same results. Any suggestions are appreciated. Not an (electronic) reg problem live every 24 hour block of time like it's your last day on earth

Re: Dual Field Alternator: Swapping the Field Wires [Re: RapidRobert] #1150441 01/19/12 10:37 AM 01/19/12 10:37 AM
Joined: Jan 2003 Posts: 5,443 Indiana Y YO7_A66 OP master
YO7_A66 OP master Y Joined: Jan 2003 Posts: 5,443 Indiana	They just told me that they are getting constant voltage output with the field wires wired per stock. They are swapping the field wiring to see if they can get the voltage to start fluctuating. Thanks 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

Re: Dual Field Alternator: Swapping the Field Wires [Re: YO7_A66] #1150442 01/19/12 12:31 PM 01/19/12 12:31 PM
Joined: Oct 2003 Posts: 3,688 Alexandria,La. B BigTerry master
BigTerry master B Joined: Oct 2003 Posts: 3,688 Alexandria,La.	wouldn't changing the field wires change the polarity of the voltage? + to -?

Re: Dual Field Alternator: Swapping the Field Wires [Re: BigTerry] #1150443 01/19/12 12:38 PM 01/19/12 12:38 PM
Joined: Jan 2003 Posts: 25,200 Upper Midwest M MoparforLife Too Many Posts
MoparforLife Too Many Posts M Joined: Jan 2003 Posts: 25,200 Upper Midwest	Quote: wouldn't changing the field wires change the polarity of the voltage? + to -? no

Re: Dual Field Alternator: Swapping the Field Wires [Re: BigTerry] #1150444 01/19/12 12:50 PM 01/19/12 12:50 PM
Joined: Aug 2007 Posts: 6,095 Valencia, España NachoRT74 master
NachoRT74 master Joined: Aug 2007 Posts: 6,095 Valencia, España	wires to brushes gives fields to create ALTERNATED CURRENT ( hence the alternator name ) by sine waves produced by the + and - fluctuations when rotor spins, creating magnetic fields what stator captures. Then Diodes hooked up to stator take care of take the correct polarity of the waves to stud and chassis, becoming on DC ( direct current ) since we are talking about - and + fluctuations on sine wave, doens't really matter what happens first on the sine wave, if - or + section of the wave. With a Charger born in Chrysler assembly plant in Valencia, Venezuela

Re: Dual Field Alternator: Swapping the Field Wires [Re: a12rag] #1150445 01/19/12 01:38 PM 01/19/12 01:38 PM
Joined: Apr 2011 Posts: 14 michigan S Sparky77 member
Sparky77 member S Joined: Apr 2011 Posts: 14 michigan	I ussally test mine by grounding out one of the wires going to the regulator LETS TAKE THIS #$^&&*#@ OUT AND SEE IF WE CAN GET IT TO DRIP PARTS Sparky 72 CUDA 440 10.10 1/4 72 Challenger 340 Rallye..sunroof car

Re: Dual Field Alternator: Swapping the Field Wires [Re: Sparky77] #1150446 01/19/12 02:22 PM 01/19/12 02:22 PM
Joined: Jan 2003 Posts: 5,443 Indiana Y YO7_A66 OP master
YO7_A66 OP master Y Joined: Jan 2003 Posts: 5,443 Indiana	I am afraid that they are not going to find anything wrong and then I am back to step one on trying to figure out what is causing the ammeter/voltage fluctuations. If it does come back with no issues, then I am planning on pulling one fuse at a time while watching the ammeter/voltage gauge to see if I can locate a circuit that clears it up. I was also thinking of buying a cheap stock alternator to test on the car too to see if there is any change. Thanks for the replies. 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

Re: Dual Field Alternator: Swapping the Field Wires [Re: YO7_A66] #1150447 01/19/12 03:57 PM 01/19/12 03:57 PM
Joined: Apr 2011 Posts: 14 michigan S Sparky77 member
Sparky77 member S Joined: Apr 2011 Posts: 14 michigan	i have found in the past that a bad regulator or a poor ground on the regulator to body can cause that....check all grounds that seems to be something thats always under rated .... body to motor a quick jumper to the motor to body will tell you Sparky LETS TAKE THIS #$^&&*#@ OUT AND SEE IF WE CAN GET IT TO DRIP PARTS Sparky 72 CUDA 440 10.10 1/4 72 Challenger 340 Rallye..sunroof car

Re: Dual Field Alternator: Swapping the Field Wires [Re: Sparky77] #1150448 01/19/12 04:12 PM 01/19/12 04:12 PM
Joined: Jan 2003 Posts: 5,443 Indiana Y YO7_A66 OP master
YO7_A66 OP master Y Joined: Jan 2003 Posts: 5,443 Indiana	Sparky, The VR is bolted into the firewall in the stock location. Both of the mounting bolts have ground wires going to different grounds in the engine compartment. I can take a voltmeter and put the "+" lead on the "+" battery post and the "-" lead on either one of the VR mounting screws or the VR ground strap (just below the connector), and I get a battery reading. Thank you for the reply. 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

Re: Dual Field Alternator: Swapping the Field Wires [Re: NachoRT74] #1150449 01/19/12 04:23 PM 01/19/12 04:23 PM
Joined: Jun 2008 Posts: 1,822 Colorado D denfireguy top fuel
denfireguy top fuel D Joined: Jun 2008 Posts: 1,822 Colorado	Quote: wires to brushes gives fields to create ALTERNATED CURRENT ( hence the alternator name ) by sine waves produced by the + and - fluctuations when rotor spins, creating magnetic fields what stator captures. Then Diodes hooked up to stator take care of take the correct polarity of the waves to stud and chassis, becoming on DC ( direct current ) since we are talking about - and + fluctuations on sine wave, doens't really matter what happens first on the sine wave, if - or + section of the wave. Exactly right. Except in Australia where the car keeps trying to drive on the wrong side of the road and the fields should be changed. Seriously, even if you turned the alternator backwards, the full wave rectifier bank will produce the proper voltage polarity. 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: Swapping the Field Wires [Re: denfireguy] #1150450 01/19/12 09:26 PM 01/19/12 09:26 PM
Joined: Jan 2003 Posts: 5,443 Indiana Y YO7_A66 OP master
YO7_A66 OP master Y Joined: Jan 2003 Posts: 5,443 Indiana	My dash lights and my dome lights are fluctuating with the ammeter/voltage gage. Would the dash voltage regulator affect the ammeter/battery voltage reading if it was bad? What about a bad battery? Thanks again. Just thinking out loud. 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

Re: Dual Field Alternator: Swapping the Field Wires [Re: John_Kunkel] #1150451 01/20/12 10:41 AM 01/20/12 10:41 AM
Joined: Sep 2003 Posts: 1,688 Marlboro, NY, USA R Rick_Ehrenberg top fuel
Rick_Ehrenberg top fuel R Joined: Sep 2003 Posts: 1,688 Marlboro, NY, USA	Quote: Powermaster's observation is correct; if swapping the field wires changes the output, the alternator is faulty...even if it works that way. Exactly. That would be conclusive proof of field-coils(rotating)-to-ground current leakage. This kind of stuff shows up more and more as the "cores" get older. Good rebuilders use an instrument called a Hi-pot to check for leakage, but don't count on that. This is why the all-new alternators, even though Chinese, are probably a better bet (Autozone Duralast Gold, etc.) Rick

Re: Dual Field Alternator: Swapping the Field Wires [Re: DAYCLONA] #1150452 01/20/12 01:35 PM 01/20/12 01:35 PM
Joined: Nov 2004 Posts: 9,312 SoCal 68HemiB master
68HemiB master Joined: Nov 2004 Posts: 9,312 SoCal	Quote: Maybe Moparts member 68HemiB will chime in, he's an xpert on "dual field" alternators and their inner workings I know it's been almost two weeks, but I cannot let Mike down on this point. Most knowledgeable folks on moparts will cringe when they see someone use the term posi when applied to a limited-slip differential installed in a Mopar. Well, it's like fingers on a chalkboard to me when I read "dual field". An ISOLATED FIELD alternator as is being discussed here might have two field connections, but there is but a single field circuit inside the alternator. Please stop it, everyone. Down to just a blue car now.

Re: Dual Field Alternator: Swapping the Field Wires [Re: 68HemiB] #1150453 01/20/12 01:37 PM 01/20/12 01:37 PM
Joined: May 2003 Posts: 6,561 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,561 Downtown Roebuck Ont	Quote: Quote: Maybe Moparts member 68HemiB will chime in, he's an xpert on "dual field" alternators and their inner workings I know it's been almost two weeks, but I cannot let Mike down on this point. Most knowledgeable folks on moparts will cringe when they see someone use the term posi when applied to a limited-slip differential installed in a Mopar. Well, it's like fingers on a chalkboard to me when I read "dual field". An ISOLATED FIELD alternator as is being discussed here might have two field connections, but there is but a single field circuit inside the alternator. Please stop it, everyone. Kevin

Re: Dual Field Alternator: Swapping the Field Wires [Re: Twostick] #1150454 01/20/12 02:40 PM 01/20/12 02:40 PM
Joined: Jan 2003 Posts: 5,443 Indiana Y YO7_A66 OP master
YO7_A66 OP master Y Joined: Jan 2003 Posts: 5,443 Indiana	If Powermaster tells me that their final tests show that it is a good alternator, should I look for another alternator? This one is out of warranty by about 6 months. Thanks a bunch!! 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

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