Where to buy correct alternator for a 1969 340 swinger non a/c car
The trouble is on the feed to the rotor. The field current control only has three positions. On, Off and on through the resistors. The electronic version I think is the same.
So here's what happens.
Resistance of the rotor is 1.7 Ohms instead of 3.5 Ohms.
Power is supplied at the same voltage. lets say its 14 Volts.
Every time the regulator connects directly, the rotor draws power based on the 1.7 ohm windings.
Lower resistance results in more current as well as more power. That's how we end up with 6 to 7 amps flowing through the regulator and associated wiring.
It's only supposed to be drawing 2.75 Amps max at 12 volts. So maybe 3 amperes at 14 Volts.
I could be wrong but seems like this is one of the issues with rebuilt alternators.
It fit with what I was observing when swapping alternators and noticed the revised squareback seemed to be the most difficult one for the regulator to control AND the one that was always involved with regulators failing. These were all transistorized versions of the points regulator. Several from Mopar performance, and Standard.
I think its also hard on the wiring. The A-bodies, at least these years, often got 16 and 18 gage ignition and field wiring.
'69 shop manual shows the wiring a little different than the other years and if so, then the wire to the regulator is 16 ga. which is a good thing.
So the key switch connection, blue ignition wire, and connectors are only seeing around 5 to 6 amps at most.
The regulator and green 18 gage connecting wire are only seeing around 3 amps at most.
The fusible links in the regulator did not change in '69. I don't know their limit. My call to Standard Motor about the capability of their solid state version of that regulator failed to generate an answer. Their tech person only had the physical dimensions of the unit. :rolleyes:
Its true the rotor that generates a stronger field should not need to be full fielded as long or as often as a weaker rotor.
But whenever current is flowing its going to be higher than factory planned on. How long/how many times can it do it that? I don't know. I do know I went through a lot of regulators when using alternators that had such rotors.
True Mike. At least on the output side.
The trouble is on the feed to the rotor. The field current control only has three positions. On, Off and on through the resistors. The electronic version I think is the same.
So here's what happens.
Resistance of the rotor is 1.7 Ohms instead of 3.5 Ohms.
Power is supplied at the same voltage. lets say its 14 Volts.
Every time the regulator connects directly, the rotor draws power based on the 1.7 ohm windings.
Lower resistance results in more current as well as more power. That's how we end up with 6 to 7 amps flowing through the regulator and associated wiring.
It's only supposed to be drawing 2.75 Amps max at 12 volts. So maybe 3 amperes at 14 Volts.
I could be wrong but seems like this is one of the issues with rebuilt alternators.
It fit with what I was observing when swapping alternators and noticed the revised squareback seemed to be the most difficult one for the regulator to control AND the one that was always involved with regulators failing. These were all transistorized versions of the points regulator. Several from Mopar performance, and Standard.
I think its also hard on the wiring. The A-bodies, at least these years, often got 16 and 18 gage ignition and field wiring.
'69 shop manual shows the wiring a little different than the other years and if so, then the wire to the regulator is 16 ga. which is a good thing.
So the key switch connection, blue ignition wire, and connectors are only seeing around 5 to 6 amps at most.
The regulator and green 18 gage connecting wire are only seeing around 3 amps at most.
The fusible links in the regulator did not change in '69. I don't know their limit. My call to Standard Motor about the capability of their solid state version of that regulator failed to generate an answer. Their tech person only had the physical dimensions of the unit. :rolleyes:
Its true the rotor that generates a stronger field should not need to be full fielded as long or as often as a weaker rotor.
But whenever current is flowing its going to be higher than factory planned on. How long/how many times can it do it that? I don't know. I do know I went through a lot of regulators when using alternators that had such rotors.