Hello,
A friend of me is busy reconditioning the charging system of one of his Farmall tractors and needs to polarise his generator, but we are not quite sure how to do it.
Can maybe anybody give a instruction to us?
Thanks in advance.
Polarisation of generator
Polarisation of generator
Best regards
Emiel
N 1937, E27N 1948, 8N 1949, E27N 1950, E1A Diesel 1953, E1ADKN PP 1956, Dexta 1959, NH Clayson M103 1964
Emiel
N 1937, E27N 1948, 8N 1949, E27N 1950, E1A Diesel 1953, E1ADKN PP 1956, Dexta 1959, NH Clayson M103 1964
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henk
- Site Governance Team & Expert Team
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Hello Emiel,
I have copied this text long ago from the old board.
Don't know who wrote this.
Amps generator NFM
The rate of charge from your dynamo should only be about 11 amps.
This was the standard charge rate for a Ford dynamo until the introduction of the 22 amp dynamo on the Ford Force "Y" series tractors. So if you are getting up to 30 amps you are way overcharging.
The maximum permissible output from your dynamo is 13 amps.
To Polarize: briefly touch (less than 1 second) regulator BAT terminal to GEN terminal (with the wiring hooked up but before you start the engine.
A way to test whether the regulator or the generator is ok.
Connect the outgoing lead again, and on the regulator connection I put a lose lead. I installed the ampere and the volt meters on the outgoing connection of the generator, and started the engine. No results on the meters. Than I put the other end of the lead on the regulator connection, on the – pool of the battery. You can do this only for a very short time, because you overrule the regulator and it could get out of hand. The result was 14 volts and 19 amperes. This told me that failure is the regulator.
I have copied this text long ago from the old board.
Don't know who wrote this.
Amps generator NFM
The rate of charge from your dynamo should only be about 11 amps.
This was the standard charge rate for a Ford dynamo until the introduction of the 22 amp dynamo on the Ford Force "Y" series tractors. So if you are getting up to 30 amps you are way overcharging.
The maximum permissible output from your dynamo is 13 amps.
To Polarize: briefly touch (less than 1 second) regulator BAT terminal to GEN terminal (with the wiring hooked up but before you start the engine.
A way to test whether the regulator or the generator is ok.
Connect the outgoing lead again, and on the regulator connection I put a lose lead. I installed the ampere and the volt meters on the outgoing connection of the generator, and started the engine. No results on the meters. Than I put the other end of the lead on the regulator connection, on the – pool of the battery. You can do this only for a very short time, because you overrule the regulator and it could get out of hand. The result was 14 volts and 19 amperes. This told me that failure is the regulator.
Kind regards, Henk
Fordson New Major February 1957 Mark I
Fordson New Major February 1957 Mark I
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Aussie Frank
- True Blue
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Hi Emiel,
The simple way to polarise a generator is to apply battery voltage (positive or negative) to the field terminal for a second or so. The field terminal is normally marked "F" and the output "D". That is if it is labeled like a lucas generator. Normally the field will be a small terminal and the output a large terminal. To be safe disconnect the wire going to the terminal marked "F" or the small terminal and touch the battery wire to it for a second or so. Make sure the correct terminal on your battery is connected to ground and all will be well. The momentary amount of current flowing in the right direction will give a small amount of magnetic field to the field magnets that will ensure that the generator will charge with the right polarity. Generators are not very fussy, they will normally take on the polarity of the battery without too much fuss even if they are wired wrong. Alternators however will not. If you wire them backwards they will tell you by letting the magic electronic smoke out right away. They never work again after that. The Farmall should be fine even if you do nothing. It should polarise itself so long as you have a good battery wired the right way when you start it. If it doesn't charge it is more likely to be wired wrong than not polarised correctly.
Regards, Frank.
The simple way to polarise a generator is to apply battery voltage (positive or negative) to the field terminal for a second or so. The field terminal is normally marked "F" and the output "D". That is if it is labeled like a lucas generator. Normally the field will be a small terminal and the output a large terminal. To be safe disconnect the wire going to the terminal marked "F" or the small terminal and touch the battery wire to it for a second or so. Make sure the correct terminal on your battery is connected to ground and all will be well. The momentary amount of current flowing in the right direction will give a small amount of magnetic field to the field magnets that will ensure that the generator will charge with the right polarity. Generators are not very fussy, they will normally take on the polarity of the battery without too much fuss even if they are wired wrong. Alternators however will not. If you wire them backwards they will tell you by letting the magic electronic smoke out right away. They never work again after that. The Farmall should be fine even if you do nothing. It should polarise itself so long as you have a good battery wired the right way when you start it. If it doesn't charge it is more likely to be wired wrong than not polarised correctly.
Regards, Frank.
Just a small comment on polarising the dynamo. It is recommended that all the wires are removed and a wire taken from the output terminal of the battery to the Field terminal. This is applied for a short period.
If the dynamo is run with the wrong polarity for long, very expensive "magic electron smoke" can be generated. I have seen some costing around £300,000.00.
The tractor was run with the dynamo wrongly polarised, it was parked in the shed overnight, the points of the regulator were welded shut, the battery tried to motor the dynamo, the fan belt was too tight and the dynamo could not turn the engine, the wiring loom started to burn, the tractor went up in smoke along with the other tractors in the shed and the new combine plus the shed and many tons of hay!
I used the actual regulator for many years when training operators and teaching electrics and electronics, as a reason why you always check polarity even when fitting a new dynamo. That story details came from the fire investigation report.
If the dynamo is run with the wrong polarity for long, very expensive "magic electron smoke" can be generated. I have seen some costing around £300,000.00.
The tractor was run with the dynamo wrongly polarised, it was parked in the shed overnight, the points of the regulator were welded shut, the battery tried to motor the dynamo, the fan belt was too tight and the dynamo could not turn the engine, the wiring loom started to burn, the tractor went up in smoke along with the other tractors in the shed and the new combine plus the shed and many tons of hay!
I used the actual regulator for many years when training operators and teaching electrics and electronics, as a reason why you always check polarity even when fitting a new dynamo. That story details came from the fire investigation report.
Fordson Tractor Pages, now officially linked to: Fordson Tractor Club of Australia, Ford and Fordson Association and Blue Force.
Brian
Brian
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Aussie Frank
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Hello Brian,
I stand corrected. I am only working on anecdotal evidence from car radio fitters from the late 60s that have changed cars from positive to negative earth with no more than swapping the battery terminals. Certainly if the cut out terminals were to be welded together lots of problems would occur. Normally if an engine was started with an incorrectly polarized generator the output would be swamped by the battery when the cutout connected. Polarity would only remain reversed for a moment and the field would be supplied with the correct polarity, most regulators survived this without any trouble and without welded contacts. The important thing is to polarize the field coil, hence I said connect the battery to the field to magnetize it and to make sure no other wires were connected to the field. Connections to the armature are irrelevant.
Regards, Frank.
I stand corrected. I am only working on anecdotal evidence from car radio fitters from the late 60s that have changed cars from positive to negative earth with no more than swapping the battery terminals. Certainly if the cut out terminals were to be welded together lots of problems would occur. Normally if an engine was started with an incorrectly polarized generator the output would be swamped by the battery when the cutout connected. Polarity would only remain reversed for a moment and the field would be supplied with the correct polarity, most regulators survived this without any trouble and without welded contacts. The important thing is to polarize the field coil, hence I said connect the battery to the field to magnetize it and to make sure no other wires were connected to the field. Connections to the armature are irrelevant.
Regards, Frank.
Frank,
Was not saying you were wrong, just emphasising the need to disconnect the output lead from the dynam before "flashing" the Field terminal.
The dynamo will quite easily overcome the battery and charge it in reverse making the positive terminal negative and the negative terminal positive.
When this happens you realise that the headlights would suck light in instead of putting light out which could be a bit dodgy if you were relying on them, not to mention the windscreen wipers pouring rain onto the screen! 
Was not saying you were wrong, just emphasising the need to disconnect the output lead from the dynam before "flashing" the Field terminal.
The dynamo will quite easily overcome the battery and charge it in reverse making the positive terminal negative and the negative terminal positive.
When this happens you realise that the headlights would suck light in instead of putting light out which could be a bit dodgy if you were relying on them, not to mention the windscreen wipers pouring rain onto the screen!
Fordson Tractor Pages, now officially linked to: Fordson Tractor Club of Australia, Ford and Fordson Association and Blue Force.
Brian
Brian
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Jerry Coles
- True Blue
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- Location: Camerton, Bath, UK
Generator Polarisation
Hi Folk
A word of caution!
You are all assuming that the polarisation is achieved by flashing the Field terminal from the +ve battery post.
This is OK for 99.99% of generators BUT!
I was asked many years ago whilst in the Army to take a look at a young soldiers car as he had blown up 3 generators and 2 regulators and it was very close to Christmas and he wanted to get home.
It took me a minute before the penny dropped and taking a look at maybe 5 other vehicles in the Army workshop did I realise that the car in question was a German Ford Taunus V4 engine and that it ran anti-clockwise. It was the angle of the fan blades that had got me thinking! Anyway I pulled of both battery connectors and cross wired it and flashed it and it then charged fine. Running the opposite direction it was "sucking" from the battery and not "blowing" hence the burnt out regulators and generators.
My tuppence worth!
Regards to all on this fine site.
A word of caution!
You are all assuming that the polarisation is achieved by flashing the Field terminal from the +ve battery post.
This is OK for 99.99% of generators BUT!
I was asked many years ago whilst in the Army to take a look at a young soldiers car as he had blown up 3 generators and 2 regulators and it was very close to Christmas and he wanted to get home.
It took me a minute before the penny dropped and taking a look at maybe 5 other vehicles in the Army workshop did I realise that the car in question was a German Ford Taunus V4 engine and that it ran anti-clockwise. It was the angle of the fan blades that had got me thinking! Anyway I pulled of both battery connectors and cross wired it and flashed it and it then charged fine. Running the opposite direction it was "sucking" from the battery and not "blowing" hence the burnt out regulators and generators.
My tuppence worth!
Regards to all on this fine site.
Jerry Coles
Camerton, Bath, UK
West Highland White Terriers, Dexta's, E27N's and DUKW's
Camerton, Bath, UK
West Highland White Terriers, Dexta's, E27N's and DUKW's
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Aussie Frank
- True Blue
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- Joined: Wed Apr 16, 2008 10:49 am
- Location: Melbourne Australia
Oops After having had some sleep and having re read my post I now realise what came out of my keyboard. What I was trying to say first and formost is that flashing the field on a generator to polarise it only works on a generator. You can not change the polarity of an alternator in this way. If you put the battery into a vehicle with an alternator the wrong way around instant electrical destruction and possible personal injury will ocur. As many tractors out there have alternators fitted I thought it necessary to mention that in case somebody who may read this post later tries to change a tractor with negative earth and an alternator fitted back to positive earth as original.
The second point was just a reassurance that you have time to check your work. A generator will put up with a lot before it gives up. Check your work though is a must. All the horror stories above would have been averted if someone had simply checked to see if the generator was charging correctly when the vehicle left the shop. If the regulator is making funny buzzing sounds, the battery voltage is falling or things are getting hot then you have a problem and you need to fix it now. Flashing the field at this point or fixing the wiring stuff up will fix the problem and things will work fine, these things are tough, they take a lot of abuse. The other check worth doing after some time with the vehicle running is that the regulator is set correctly and that you are not over charging. A simple voltage measurement will show if things are set right.
Regards, Frank.
P.S. I promise to be awake the next time I post something again.
After having had some sleep and having re read my post I now realise what came out of my keyboard. What I was trying to say first and formost is that flashing the field on a generator to polarise it only works on a generator. You can not change the polarity of an alternator in this way. If you put the battery into a vehicle with an alternator the wrong way around instant electrical destruction and possible personal injury will ocur. As many tractors out there have alternators fitted I thought it necessary to mention that in case somebody who may read this post later tries to change a tractor with negative earth and an alternator fitted back to positive earth as original.The second point was just a reassurance that you have time to check your work. A generator will put up with a lot before it gives up. Check your work though is a must. All the horror stories above would have been averted if someone had simply checked to see if the generator was charging correctly when the vehicle left the shop. If the regulator is making funny buzzing sounds, the battery voltage is falling or things are getting hot then you have a problem and you need to fix it now. Flashing the field at this point or fixing the wiring stuff up will fix the problem and things will work fine, these things are tough, they take a lot of abuse. The other check worth doing after some time with the vehicle running is that the regulator is set correctly and that you are not over charging. A simple voltage measurement will show if things are set right.
Regards, Frank.
P.S. I promise to be awake the next time I post something again.