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Discussion Starter · #1 ·
I viewed a wiring diagram of a charging system for Ford internal-regulator charging system and the term "Hot in Run" was used.

What does the term mean mean? I asked this before and got no response.

Perhaps someone could refer me to another general wiring diagram that would show the wiring diagram for the charging system for a 1989 Ford f-150 six cylinder with an internal regulator.
 

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"Hot in run" means that the circuit is fed voltage only when the ign key is in the run position. Your ign switch is in the "run" position when its turned on. Your switch positions are ACC=all the way back--OFF--ON--START. Hope this helps.
 

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Discussion Starter · #3 ·
"Hot in Run", what does that mean, cont'd

Thank You!

That makes sense. If I may, I would like to ask a second related question.

This particular wire to which I am speaking goes to the "F" (field) terminal. To make this alternator to create output, I am assuming there has to have a magnetic field created and the power from the battery is what creates the magnetic field.

Does the alternator's internal regulator break this circuit in order to prevent overcharging?

If this is so, is the aforementioned circuit break a complete break or a break of controlled resistance? In other words, is the output always at the alternator's full rated output or does it vary with the voltage of the battery at any given time?
 

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dieterschmied said:
Thank You!



To make this alternator to create output, I am assuming there has to have a magnetic field created and the power from the battery is what creates the magnetic field.

Does the alternator's internal regulator break this circuit in order to prevent overcharging?

If this is so, is the aforementioned circuit break a complete break or a break of controlled resistance? In other words, is the output always at the alternator's full rated output or does it vary with the voltage of the battery at any given time?
The regulator varys the voltage that is used to excite the alternator ,it uses the battery voltage as a reference to charge the battery to to the correct state of charge.........no under charge or over charge.........within it's electrical limits. In other words if the battery's reference voltage is too low, the regulator will increase the excitation voltage to raise the battery's voltage back to the correct level. And if the voltage is too high, the reverse happens and the regulator lowers the excitation voltage to prevent over charging.
Hope this helps
Kenny
Lost your job yet? Keep buying foreign
 

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Discussion Starter · #6 ·
Thanks!

The problem that I have is that the alternator doesn't put out the required voltage. The alternator has been tested at AutoZone and it is good. Actually, I replaced the first alternator and the one being tested is the one I took off, but both have performed the same way.

If I disconnect the green field lead and reconnect, it puts out until the truck has been parked and shut down. The battery checked ok as well. Any suggestions?
 

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I don't know if the Ford alternator works the same as a GM 10si internally regulated alternator, but I think its probably similar.
- large connector post - 12 volt charge wire that runs to the battery; always connected to battery power
- wire to the dash light or a resistor; switched 12 volts from the ignition; applying power to this wire turns the alternator on and off
- 12 volt sense wire; sometimes it is just jumpered to the charge wire post, but this can make the alternator undercharge at low speed. The stock installation connects the sense wire to a point near the main junction on the firewall, where it can "sense" the voltage drop. If the sense voltage is too low (due to accessory load), it will be lower than the reference voltage, signaling the regulator to increase output.

Bruce
 
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