Alternator Field Two Wires - I Only Want One

demonboy

demonboy

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I spoke with my alternator man who put an external regulator on my alternator. He explained which wires were the field wires: there are two, +ve and -ve. However my Balmar only has one field wire input. Which of the two wires do I use? If I only use +ve, what happens to the -ve?
 
demonboy said:
I spoke with my alternator man who put an external regulator on my alternator. He explained which wires were the field wires: there are two, +ve and -ve. However my Balmar only has one field wire input. Which of the two wires do I use? If I only use +ve, what happens to the -ve?
Click to expand...

Does this alternator have an internal regulator?
 
In some alternators, one end of the field winding goes to the regulator and one to negative, called positive regulation. Balmar normally work this way.
However in some, one end of the field winding goes to the regulator and one to positive, called negative regulation. On older alternators Lucas normally did this. In fact the cct dia you posted for the Lucas confirms this I've just realised.
This could explain why your man had to disconnect both ends of the field, your alternator being a Lucas TVS.


I would say it's heavy odds that with the Balmar regulator that you have the other end of your field winding should go to negative BUT I CANNOT ABSOLUTELY GUARANTEE IT. Sorry.

Edit -
Balmar's instructions for the ARS5 regulator say that the field voltage it outputs increases up to +11V for discharged batteries i.e. full output. http://www.balmar.net/PDF/ars-5instructionsheet.pdf

Quote
Check voltage on BLUE (field) wire in wiring harness. Voltage should measure
approximately three to eleven volts, depending on the charge level of the
batteries. Field voltage increases as batteries are more deeply discharged.
Unquote

Logically this confirms what I said and the other end of field should go to -ve i.e. alternator frame.
 
Last edited:
Nigel point accepted in principle though I think highly unlikely in this instance.

It should go to the same connection point as the negative of the Balmsr regulator whether that is on the frame or isolated.
 
I'd wire the Balmar regulator to the positive field connection, and ground the negative field connection. But if the alternator's internal regulator hasn't been disabled, the Balmar won't give a proper 4-step charge cycle, it can only increase the voltage set by the internal regulator.
 
pvb said:
I'd wire the Balmar regulator to the positive field connection, and ground the negative field connection. But if the alternator's internal regulator hasn't been disabled, the Balmar won't give a proper 4-step charge cycle, it can only increase the voltage set by the internal regulator.
Click to expand...

Isn't the Balmar regulator a stand-alone multistage regulator for use with externally regulated P type alternators
 
pvb said:
It is, but the OP has bought one to use with an ordinary alternator, the regulator of which he says is "by-passed".
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He says the internal regulator has been "bypassed" and an external regulator fitted which he now wants to replace with the Balmar regulator. I assume that means that the original regulator is disconnected or disabled in some way, its function having been taken over by an external regulator. The intention now is to use the Balmar regulator in place of the external one. No ??
 
VicS said:
He says the internal regulator has been "bypassed" and an external regulator fitted which he now wants to replace with the Balmar regulator. I assume that means that the original regulator is disconnected or disabled in some way, its function having been taken over by an external regulator. The intention now is to use the Balmar regulator in place of the external one. No ??
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Yes, something like that.
 
demonboy said:
I spoke with my alternator man who put an external regulator on my alternator. He explained which wires were the field wires: there are two, +ve and -ve. However my Balmar only has one field wire input. Which of the two wires do I use? If I only use +ve, what happens to the -ve?
Click to expand...

I think I understand the problem.

The old external regulator would have required three connections to the alternator. A ground or negative, an output from the field diodes to the regulator and an input to the rotor coil . The Balmar regulator does not require a connection to the field dodes because it takes all its power from the altrnator main output or direct from the battery if there is a diode splitter involved.

You therefore need to determine which is which of the two wires added for the old external regulator . Insulate the one coming from the field diodes and connect the Balmar blue wire to the one which is connected to one of the slip ring brushes.

I am assuming that the alternator is positive regulated because the Balmar is only suitable for positive regulated alternators.
 
Troubadour, the alternator I am looking to rig the Balmar to is an old Lucas A127 (55amp), not the one I provided a circuit diagram for.

Just to recap, what you are saying: the +ve field wire from the alternator would go to the Balmar field cable (blue) and the negative field wire from the alternator would go to the alternator body itself.

Nigel - what do you mean by 'isolated' and why would this be a mistake?
 
demonboy said:
... and the negative field wire from the alternator would go to the alternator body itself. Nigel - what do you mean by 'isolated' and why would this be a mistake?
Click to expand...
Isolated means that neither terminal is connected to the body of the unit, this is quite common on marine alternators to prevent corrosion. Connecting to the body would bypass this isolation. You should connect the negative wire to the main negative terminal.
 
demonboy said:
Troubadour, the alternator I am looking to rig the Balmar to is an old Lucas A127 (55amp), not the one I provided a circuit diagram for.

Just to recap, what you are saying: the +ve field wire from the alternator would go to the Balmar field cable (blue) and the negative field wire from the alternator would go to the alternator body itself.

Nigel - what do you mean by 'isolated' and why would this be a mistake?
Click to expand...

That alternator will be the same.
Nigel's remark is correct in principle but unlikely to apply to this alternator.
So blue to field +ve, and field -ve and the Balmar regulator negative to the -ve terminal, whether that terminal is insulated or directly onto the frame.
 
Troubadour said:
That alternator will be the same.
Nigel's remark is correct in principle but unlikely to apply to this alternator.
So blue to field +ve, and field -ve and the Balmar regulator negative to the -ve terminal, whether that terminal is insulated or directly onto the frame.
Click to expand...


Great, thanks for confirming that for me.
 
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