alternator votage generator wiring

spade31

New User
I"m trying to rewire an oliver 77 that had a motorcraft alternator that was bad. There was no voltage regulator on the system and I think the wire going to the coil is at the wrong post. The tractor ran fine other than battery would not charge and drained when tractor was off(within 4 hours battery dead.) Here"s how I have it wired now.

Alternator
FLD - Volt reg F
BAT - Ammeter to + Battery
STA - not connected
GRD - Grounded

Voltage Regulator
I - not connected
A - to Positive Battery (connected at starter switch)
S - goes to ignition switch to Neg side of coil, Pos side of coil goes to distributor (I think this should be reversed but it was running this way)
F - FLD

Questions: Do I need to change the wire to the coil?
Does the coil get power from the S terminal from the voltage regulator?

Thanks
Ryan
 
Looking at diagram I have for Motorcraft alternator with external regulator it wires:

Alternator -- Regulator
GRD Ground G

FLD . . . . . . F
STA . . . . . . S
BAT . . . . . . A
The BAT-A connection would also go to Ammeter (if used) and then to hot battery connection which is often made at the starter solenoid

There should then be a wire from the alternator side of the ammeter to the input to ignition and light switches. The ignition output of the switch would go to the coil.

With alternator it should be negative ground. Connect the ammeter so that it shows negative with light and/or ignition switch on and engine not running.

With negative ground the negative post on coil goes to distributor.

I on regulator is for Indicator or Idiot light. It would not be necessary with an ammeter
 
<img src = "http://www.gondtc.com/~blweltin/Bob/SimpleFordAlternatorCircuit2.jpg">

Arrow/wire "To ign." would go direct to (+) terminal on coil if using a 12 Volt coil that does NOT need a ballast resistor, or to the ballast resistor and on to the coil's (+) terminal if the coil being used REQUIRES a ballast resitor.
 
Thanks for the help. Is it normal for the coil to work if it was wired backwards (+ to distributor); would the spark jump the gap in a reverse direction?

I have already corrected it the way Bob showed.

Thanks for all the help.
 
"Is it normal for the coil to work if it was wired backwards (+ to distributor); would the spark jump the gap in a reverse direction?"

YES!

Spark is just a little less efficient under load if polarity is reversed.
 
EXACTLY,,,,,,,,Same as its easier in a vacuum tube to emit electrons off a heated cathode up to a cooler anode (PLATE). Its easier to emit electrons off the hot spark plug electrode tip to a relatively cooler ground strap.....If reversed the coil has to rise to a higher voltage before current arc jumps the plugs gap and its less efficient because more energy is wasted as heat in the coil.

GOTTA LOVE SPARKY CHAT

John T
 

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