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How to polarize 6v + earth Lucas generator...?

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I'm not certain what the polarizing procedure is, so i will appreciate if you can instruct me how to polarize the generator.

I seem to recall "D" terminal is the main brush and "F" terminal are the field coils; motoring the generator requires "F" and "D" terminals connected to the negative battery terminal and positive battery terminal connected to generator body, correct?

Thanks in advance and kind regards.

ps.  The regulator is a new solid state unit, i can only assume it is a properly working unit...  Using a multimeter to confirm the generator is charging, i will appreciate if you will tell me how to carry out the test.

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I seem to recall "D" terminal is the main brush and "F" terminal are the field coils; motoring the generator requires "F" and "D" terminals connected to the negative battery terminal and positive battery terminal connected to generator body, correct?

To some extent yes. You won't get the Dynamo to motor when fitted to the engine? So Polarising is-Connecting 'live' battery to the F-Field with the battery Earthed as you intend to use it. (no other wires to the dynamo while doing this exercise)

Then check dynamo for an output-F connected to D, headlamp bulb to earth-start engine, lamp should light.-This confirms dynamo function. These details are on my web site-aoservices.co.uk under Fitting the V Reg (our electronic dynamo regulator).

The only use for a Multimeter is to look if battery voltage is rising. Ammeters not reliable, often not connected correctly. Cheap digital meters pick up engine interference and read 'rubbish'.

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...for your reply.  I do understand the generator cannot be motored in situ.

Thank you for your comments how to polarize the generator which is a different procedure than polarizing the generator on my '27 Harley.

Thank you for the reference on your website for polarizing the generator.  I have printed your instructions, will review them in preparation for polarizing the generator. 

Should i expect to hear a click or see a spark when i flash the wire leading from the +battery terminal to the generator "F" terminal?  (such is the case when polarizing the Harley terminal...)

Once i know i have polarized the generator, then i will check for generator output.

If i need any clarification I will ask.

Kind regards,

Steve 

 

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Alan, following your instructions, here is the test light i made up; hopefully it is as you instructed.

i did polarize the generator, i heard a little click at the same time i saw the tiny spark, so i assume the job is done.  i think before i check the generator output with the test light, I will go out for another ride and report back.

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... will be the dynamo trying to motor against the resistance of the engine so you sound as if you're on the tright track.

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The click is a small amount of power going through the Field coil and the spark is correct. It is not any attempt to turn the dynamo as the test above puts power into the Field only not the D armature. 

Otherwise the testing looks good. Apart from the fact that it looks like you are using an indicator lamp, it will work but the lamp will blow if you give the engine a bit of a spin, Headlamp is best. Can't see why you don't check for Dynamo output before the ride though?

Just to finalise this testing, if after Polarising checking for output with a head lamp does not give an output, pull off the Earth wire (with the engine running) then reconnect it.

 

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...your comments.  Especially the advice to pull the Earth wire off if headlamp doesn't give an output while engine is running?  For my sake of learning, what does pulling the Earth wire off accomplish?  (electricals are my weak area...)

My prior comment of riding it and not testing for output was to have the hopefully pleasant surprise of watching the headlamp glow brighter and the ammeter registering on the + side of "0"...  other than that, no rational reason to not test output...  just old and a bit tired and grateful i can kick start everything i ride...

hmm...  i didn't stop to think that current straight out of the generator would blow that bulb, but it all makes sense after you mention the fact...  i do have some 35 cp headlight bulbs,so i suppose one of those might stand the test...?

Thanks again for your generous help and kind regards.  Will update after i have tested output and need be pulled the Earth wire.

 

 

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... of course right again Al. Sometimes I think my only function is to post slightly inaccurate comments so that folk wiser than I can correct them!

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Pulling the earth wire off with the engine running does this-If you use a headlamp bulb in this test, the resistance of the bulb when 'cold' is sufficient sometimes to stop the small amount of electricity generated by the residual magnetism in the Field coil iron piece from starting the Dynamo to make electricity. Pulling the Earth off, allows the F-D short then to excite the dynamo to produce electricity (with no load) then replace the Earth and bingo we have an 'excited' dynamo.

You did ask. Cheers Ian!

 


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