JohnT, help, polarizing generators debate

[Janicholson]

You are correct and I was wrong in my NO research opinion. The consensus is disconnect the F terminal and touch it to the Bat terminal or disconnect the bat terminal and flash the F terminal. Jim

 

[JMOR]

(quoted from post at 13:12:42 09/08/23) You are correct and I was wrong in my NO research opinion. The consensus is disconnect the F terminal and touch it to the Bat terminal or disconnect the bat terminal and flash the F terminal. Jim

es, I do see the "consensus" procedure in many places and agree that, "disconnect the F terminal and touch it to the Bat terminal" will get the job done, BUT that "disconnect the bat terminal and flash the F terminal" will damage the Field contacts by feeding 60+amperes through contact designed for 1.5 to 4 amperes max. Not good to feed armature current through those field contacts. Do it same as a-circuit (I.e., BATT to ARM) and that is not a problem.

 

[John T]

BOTTOM LINE SUMMARY

You POLARIZE A or B by passing current through the field windings which imparts a degree of the correct North South Magnetic Field Polarity in the soft iron poles around which the field windings are located...

Since in a Class A the fields begin at the ARM post (2 brush gennys) you jump hot battery voltage there which causes field current flow TO MAGNETICALLY POLARIZE THE GENNYS SOFT IRON FIELD POLES.......

Since in a Class B the Fields are internally grounded, if you apply hot battery voltage to the gennys FLD post you get field current flow TO MAGNETICALLY POLARIZE THE GENNYS SOFT IRON FIELD POLES.......

I prefer and advise polarization as Delco and Deere manuals state BUT REALIZE OTHER METHODS (as based on VR's internal wiring and system) can accomplish polarization. On A's I jump from BAT to ARM, while on B's I jump hot battery voltage (such as present on BAT terminal) to FLD.

DO AS YALL LIKE AND WHAT WORKS FOR YOU, I prefer what Delco and Deere manuals state but thats just me. AGAIN other methods can (based on VR internals and wiring) still polarize. Your tractor YOUR choice

John T

 

[WeirdDeere]

As always John I appreciate your easy to understand thoughts, but with enough details to digest and grasp.

Does it matter if it's a 2 brush or 3 brush? I've always treated them the same.

Brandon

 

[JMOR]

(quoted from post at 18:25:22 09/08/23) BOTTOM LINE SUMMARY

You POLARIZE A or B by passing current through the field windings which imparts a degree of the correct North South Magnetic Field Polarity in the soft iron poles around which the field windings are located...

Since in a Class A the fields begin at the ARM post (2 brush gennys) you jump hot battery voltage there which causes field current flow TO MAGNETICALLY POLARIZE THE GENNYS SOFT IRON FIELD POLES.......

Since in a Class B the Fields are internally grounded, if you apply hot battery voltage to the gennys FLD post you get field current flow TO MAGNETICALLY POLARIZE THE GENNYS SOFT IRON FIELD POLES.......

I prefer and advise polarization as Delco and Deere manuals state BUT REALIZE OTHER METHODS (as based on VR's internal wiring and system) can accomplish polarization. On A's I jump from BAT to ARM, while on B's I jump hot battery voltage (such as present on BAT terminal) to FLD.

DO AS YALL LIKE AND WHAT WORKS FOR YOU, I prefer what Delco and Deere manuals state but thats just me. AGAIN other methods can (based on VR internals and wiring) still polarize. Your tractor YOUR choice

John T

ohn, with all due respect & I say that sincerely, that B-circut procedure to apply polarization to the Field terminal is lacking the very important reminder to folks that may not be as informed as you are, to DISCONNECT THE fIELD TERMINAL FROM THE REGULATOR FIRST or risk damaging VR field contacts in the VR. You can't assume the folks know anything, as most don't even whether their system is A or B , and sure don't know how to identify one or the other.

 

[Janicholson]

I believe the pulse of current {4 amps or so) must go through the field windings, not the armature. The polarizing of the B circuit must come through the field terminal to ground. There is no connection from the armature terminal to the field windings. The spark when flashing a B type is very weak compared to the substantial spark when flashing an A type because the A type is also passing bat volts directly through the armature windings. Jim

 

[JMOR]

(quoted from post at 13:23:11 09/09/23) I believe the pulse of current {4 amps or so) must go through the field windings, not the armature. The polarizing of the B circuit must come through the field terminal to ground. There is no connection from the armature terminal to the field windings. The spark when flashing a B type is very weak compared to the substantial spark when flashing an A type because the A type is also passing bat volts directly through the armature windings. Jim

im, just look at the VR diagram and see the Field connection to Armature via the normally closed Field control contacts. That is why you remove the gen Field to VR Field connecting wire when polarizing by this method. You do NOT want the high armature current going thru those field contacts.

 

[JMOR]

As long as I'm on the subject, might as well also show what/how wrong polarization technique damages an A-ckt system.

 

[WeirdDeere]

Do you happen to have a similar
illustration for Bs? I'm just trying to
understand the difference between the two.
I know that everything I've messed with are
A gens

 

[JMOR]

(quoted from post at 15:48:23 09/09/23) Do you happen to have a similar
illustration for Bs? I'm just trying to
understand the difference between the two.
I know that everything I've messed with are
A gens

lready posted but here it is again. It is the 60A dashed path that is the problem if done wrong.
If do an A-ckt polarization technique on a B-ckt generator/VR system, all is well, fine and good, as shown here with BATT to ARM jumper and furthermore a current also flows BATT at VR terminal,TO generator ARM terminal, just as it does in the A-ckt system.

Just note the different terminal arrangements on A vs B.

 

[620 John]

Best way I've always been able to remember which ones to jump: Touch BAT to ARM "A" terminal to polarize, touch BAT to Field "F" and you're "F**ed".


BTW being a JD guy I've never heard about Class A and Class B type systems until now. Good discussion.

 

[JMOR]

(quoted from post at 18:35:44 09/09/23) Best way I've always been able to remember which ones to jump: Touch BAT to ARM "A" terminal to polarize, touch BAT to Field "F" and you're "F**ed".


BTW being a JD guy I've never heard about Class A and Class B type systems until now. Good discussion.

ow that is about as concise and succinct as one can put it. Very good!

 

[Tim PloughNman Daley]

I've always followed the JohnT instructions for polarizing generators. Flashing BAT power to ARM post.

I posted this somewhere and started a mini argument, from a guy who always flashed BAT to FIELD. He stated source as the JD electrical manual.

Others have been on one side or the other.

I did more digging, and apparently it depends if you have an A circuit or B circuit generator on how it's flashed.

But I'm wondering if it's even a hard and fast rule....because we both made either choice work on JD generators? I can't remember if JD used A or B type circuits.

Some more info stolen from the internet.....

---------------

Depends on the circuit in your generator. According to the Delco-Remy service bulletin dated 7-3-61, there are two different circuit types of generators:

Type A circuit - The field winding is connected to the insulated brush inside the generator and is connected to ground through the contact points in the regulator.

Type B circuit - The field winding is grounded inside the generator and is conncted to the armature circut inside the regulator.

To polarize the generator with:
Type A circuit - Momentarily connect a jumper lead between the regulator BATTERY and ARMATURE terminals after all leads have been connected, but before the engine is started.

Type B circuit - Disconnect the lead from the regulator FIELD terminal, and momentarily touch the lead to the regulator BATTERY terminal. This should be done after all other leads have been connected and before the engine is started.

Thanks to anybody!
Brandon

POLARIZING a GENERATOR depends on the CIRCUIT TYPE used and the only way to confirm the circuit is by internal inspection. You don't polarize any ALTERNATOR. You can arc-spark the CUTOUT or VOLTAGE REGULATOR depending on what system you have with a screwdriver or jumper wire. A GENERATOR will automatically be polarized correct for your system when the shop rebuilds it and motor tests it. I&T F-XX Manual has motoring test method. Polarizing is always the last step before power up when verifying wiring. Once is sufficient. Multiple attempts do nothing but won't damage unless you short out wrong terminals.

Tim Daley (MI)

 

[used red MN]

Tim, just a reminder, watch the dates of posts in this new forum layout, the “Similar threads” area below each discussion topic can mislead you. This is a steeper learning curve if you were a “Classic view” user. The last post added was 9/10/23, you added good information I am not discouraging you from that.

 

[Janicholson]

person who really understands the A/B circuits, me, can tell you that flashing either by momentarily connecting BATT to Arm polarizes either just the same, buy momentarily running current through the field coils. I have no earthly idea why a different method has long been recommended for the B-circuit, other than possibly the B_A_F terminal arrangement on the A-circuit and the A_F_B arrangement on the B_circuit might lead to someone jumpering the two left most terminals on both. That is fine for A_circuit, but on B_circuit, disastrous, because such would not only run the typical ~4 amperes thru the field coils (just as in the A_circuit), but an additional ~60 amperes through the armature via the Field contacts in the regulator. Those contacts are designed to switch ~4 amperes!

Because I have been corrected, I would also indicate the need to correct the right hand illustration to show the disconnected field wire from the VR in the illustration you provide. There are those that look at drawings as a plan of attack. You have clearly described ti issue in the text. The green and purple dots above the diagramatic field should show no connection, and there might be a note there. Jim

 

[buickanddeere]

Just loosen the fan belt so the generator pulley can spin freely . Use a wooden popsicle stick to push the cut out contacts together inside the regulator . The generator pulley should turn and the generator will be polarized .

 

[TomWK]

POLARIZING a GENERATOR depends on the CIRCUIT TYPE used and the only way to confirm the circuit is by internal inspection. You don't polarize any ALTERNATOR. You can arc-spark the CUTOUT or VOLTAGE REGULATOR depending on what system you have with a screwdriver or jumper wire. A GENERATOR will automatically be polarized correct for your system when the shop rebuilds it and motor tests it. I&T F-XX Manual has motoring test method. Polarizing is always the last step before power up when verifying wiring. Once is sufficient. Multiple attempts do nothing but won't damage unless you short out wrong terminals.

Tim Daley (MI)

The diagrams of generator type A vs B in 2 or 3 brush configurations was very helpful. Thank you. I have a '48 model C Allis, with a 2-brush 6v generator of un-identifiable manufacture, obviously rebuilt, with visible damage to the rotor, like someone stuck a screwdriver in there while it was turning. I'm about to replace it with a used Allis Chalmers Delco 3-brush 6v generator I got from 'Northstar Store' on eBay. I know I have to polarize the setup, and I didn't know what type I have.

I have a 4 lug voltage regulator and John T's clear instruction from this forum how to wire it up.

A picture really is worth a thousand words. Thanks again.