dodge68charger
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M&H Harness Offers a Harness For Different Style Alternators. Thank You
Alternator Identification?
- Thread starter dodge68charger
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M&H Harness Offers a Harness For Different Style Alternators. Thank You
That is a Square back and they started around 1972 they were all dual field. 1970 Started using dual field but it was still round back.
you can ground one field terminal and use it on you single field 1960-1969 mopar.
Square back they changed to the diode bridge and was a better design.
you can ground one field terminal and use it on you single field 1960-1969 mopar.
Square back they changed to the diode bridge and was a better design.
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hunt2elk
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Are the sq. back ones 60 amp ?
66Satellite47
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The '70 dual field still used the earlier style diode arrangement -round back. '71's were much simpler to replace diodes.
66Satellite47
Well-Known Member
A few amp versions were available.
Dual field began in 70 but still being round back
squarebacks began on 72
BUT the one on pic seems to be a laters squareback alt with alt housings meeting in the middle. Earliers still got the stator visible between botn housing halfs
not all dual field or squarebacks are 60 amps. But laters use to be minimun 60 because they got a wider stator than earliers squarebacks
later and earliers squarebacks got one of the brush isolator diff design and don’t interchange.
squarebacks began on 72
BUT the one on pic seems to be a laters squareback alt with alt housings meeting in the middle. Earliers still got the stator visible between botn housing halfs
not all dual field or squarebacks are 60 amps. But laters use to be minimun 60 because they got a wider stator than earliers squarebacks
later and earliers squarebacks got one of the brush isolator diff design and don’t interchange.
Earliers got the one on the left, laters the one on the right
The other one is the same on both
The other one is the same on both
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The diodes on a square back unit are easier to change but don't cool as well as the round back units, and in my opinion, are more fragile and subject to failure if overloaded or subjected to transient voltage spikes. The first design (1960) round back alternators used germanium diodes, later were switched to silicon diodes for better reliability and capacity. The diodes AND the stator windings determine the amp capacity of the alternator...the rotors were almost the same in all years.
BOB RENTON
BOB RENTON
1 Wild R/T
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Those are in fact all single field alternators....
The one with two field connections just gives you access to both ends of the same field winding....
The one with a single field connection has the one end of the field winding grounded...
The one with two field connections just gives you access to both ends of the same field winding....
The one with a single field connection has the one end of the field winding grounded...
RM23M9A
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2 Field, problem I have, is when using this 2 field, word is, "ONE TERMINAL MUST BE GROUNDED", ok, which one?!
Assuming they BOTH exert voltage, but they appear different from looking at the way theyre attatched or circuited into the casing..
I recently installed a NEW M&H harness for 6 Pack with Electronic Ignition, has a GREEN and a BLUE field wire, plus BATT lead. Before my little fire, I know GREEN wire AND Blue were BOTH connected. Im lost here. When I started up car with new harness, the blue wire began to smoke! Luckily I shut it down saving the harness, but FUSIBLE LINK was beginning to melt!
Uuugh, then there is a long blue lead that seems to go nowhere! I can wrap it around other wiring near bulkhead.
This blue wire still has the HU199BM tag on it. No one at Year One knows anything about the actual harnesses they sell. Other than suggesting a harness for applications..
Dual field alts are matched with electronic regulators. They get green and blue wires. Blue is Ign circuit (+) while green is closing circuit to ground via the elect regulator being this the side which gets the regulation pulsating signal inside the reg ( transistorized, not anymore mechanical like on earliers which made the same but with the ign circuit signal instead ) so that's the reason why both brushes become isolated. If you got grounded one of the alt brushes and conected the blue wire used on dual field wiring there, you got shorted the wiring as soon got ign key in RUN. If you were conected the green wire from the dual field wiring on a grounded brush, wouldn't get a short but somehow bypassed the reg, so were full fielding the alt but wouldn't burn anything. But it seems unfortunately got the blue wire straight to the grounded brush.
Electronic regulator matched with dual field alts need both brushes isolated as mentioned. These get the constant source being the positive coming from ign circuit. On single field, the constant signal is ground, hence the reason why these need the brush grounded and is how the single field alts are build, getting one brush straight attached to the alt housing without any plastic insert, so ground the brush on a dual field alt is emulating the older setup.
When needing to ground a dual field alt to use a mech regulator system which only gets a green wire to the alt, this time positive but pulsating to be the regulated source, any of the brushes can be grounded and the other one would get the green wire. If you conect the green wire coming with the mech reg setup to the now grounded brush, will short out the system like the previous example, burning wires. This happens if the method you use to ground the brush is replace the isolation washer with a metallic one. That's my fav one ( and mostly sure what you got without really need for that ) since makes a clean installation, but if you keep the brush prong exposed, is easy to make the mistake to conect the wire there and get a short. I recommend to clip off the prong or somehow bend it to make it imposible to get it connected.
The other method could be use a jumper wire to ground the brush, which would keep the prong in use and imposible to mix them up, but it makes somehow an uglier installation (just about view preferences).
Electronic regulator matched with dual field alts need both brushes isolated as mentioned. These get the constant source being the positive coming from ign circuit. On single field, the constant signal is ground, hence the reason why these need the brush grounded and is how the single field alts are build, getting one brush straight attached to the alt housing without any plastic insert, so ground the brush on a dual field alt is emulating the older setup.
When needing to ground a dual field alt to use a mech regulator system which only gets a green wire to the alt, this time positive but pulsating to be the regulated source, any of the brushes can be grounded and the other one would get the green wire. If you conect the green wire coming with the mech reg setup to the now grounded brush, will short out the system like the previous example, burning wires. This happens if the method you use to ground the brush is replace the isolation washer with a metallic one. That's my fav one ( and mostly sure what you got without really need for that ) since makes a clean installation, but if you keep the brush prong exposed, is easy to make the mistake to conect the wire there and get a short. I recommend to clip off the prong or somehow bend it to make it imposible to get it connected.
The other method could be use a jumper wire to ground the brush, which would keep the prong in use and imposible to mix them up, but it makes somehow an uglier installation (just about view preferences).
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As I understand, you have installed a later engine harness supporting the ’70 and later electronic regular (two field wires) on a ’69? As mentioned, you need a ’70 or later “isolated field” alternator where neither field terminal has been grounded to its case. Connecting the blue field wire to grounded field brush/terminal will burn wires as described. If your current alternator has two terminals and worked with the mechanical regulator previously to installing the later harness, it is a later isolated field alternator with one brush/terminal grounded. Rebuilders will substitute an insulating washer under a brush mounting screw with a metal washer to easily configure a later alt for use on a pre ’70 application.
Pull off both field terminal connections, check for continuity from the terminals to the case, should not be any, correct as needed.
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Yes...you are correct on all points except one....the diode bridge arrangement, especially the negative group was prone to diode failures because of inadequate cooling. IMO, the individual pressed in, in their respective heat sink assemblies were superior. I've experienced several negative diode failures over the past several years. Aftermarket replacement parts as well as NOS Mopar are available. The origional round back alternators used germanium diodes, very suseptable to failures, were later switched to silicon diodes, which were more forgiving, with regard to overloads and transients.
BOB RENTON
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