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Subject: Polarizing Generator

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Gary    Posted 01-09-2021 at 10:52:44 [URL] [DELETE]        [Reply] [Email]  
  • Polarizing Generator
  • Polarizing Generator
    I replaced the generator on my Ford 641, 6 volt tractor. The generator has one heavy wire attached to the end and 2 smaller wires attached on the side. The alternator appears to be a Ford type. Do I need to polarize the generator ? Is this accomplished by disconnecting the field wire and quickly touching it to the battery terminal ? I replaced the generator because I was starting to hear a grinding noise inside. It was still charging OK. Thanks for your replies. Gary

    Gary    Posted 01-10-2021 at 21:14:45 [URL] [DELETE]        [Reply] [Email]  
  • Re: Polarizing Generator
  • Delete the word alternator and insert generator.

    Tim Daley(MI)    Posted 01-10-2021 at 09:33:32 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Polarizing Generator
  • Gary-
    First, are you talking about a generator or an alternator –you mention both and there is a difference so which is it? To answer your 2nd question first, NO! Polarization is done with NO POWER applied. Polarizing can be done internally on the generator as well it is just easier to do with the VR when all are mounted. The rattling noise you heard was probably a worn out bearing in the GEN or badly worn brushes rubbing on the commutator. Your shop rebuild guy should have fixed this then tested using the 6V/POS GRN setup and it would have set polarity on its own. Next, JMOR is the resident electrical guru around here and has diagrams and text to show correct wiring. You need your ESSENTIAL MANUALS, OEM Owner Manual and I&T FO-19 or FO-20 Manual to use as references. It's important you should know what your electrical system consists of and operates on. There are two circuit designs on generators, the 'A' Circuit, and the 'B' Circuit -see diagrams below. The first early 9N, the NAA, and all generators after used the 'B' Circuit design. Polarizing each circuit is different and if using the wrong one on a 'B' Circuit, can fry the VR altogether. The NAA, 600, 800, and 900 Models all used the 20-AMP; 'B' Circuit Design; 3-Wire/2-Brush Unit with a Voltage Regulator -see drawing. Either way, GEN or ALT, you need a fan belt tensioning device attached in order to charge the battery. Do you and how well do you know how to use a VOM? Just curious, how do you determine it is FORD unit?

    FORD OEM 600/800 OWNER-OPERATOR’S MANUAL:

    FORD NAA/600/800/900 TRACTOR ELECTRICAL WIRING:


    POLARIZING AN “A” CIRCUIT DESIGN or “B” CIRCUIT DESIGN:

    -Diagrams courtesy of JMOR

    Tim Daley(MI)

    Gary    Posted 01-10-2021 at 21:19:43 [URL] [DELETE]        [Reply] [Email]  
  • Re: Polarizing Generator
  • Generator housing has FORD stamped on it.

    JMOR    Posted 01-10-2021 at 00:17:56 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Polarizing Generator
  • you got it.

    Gary    Posted 01-10-2021 at 01:16:48 [URL] [DELETE]        [Reply] [Email]  
  • Re: Polarizing Generator
  • JMOR: Thanks for the reply. One more question, Do I carry out this procedure while the key is in the "on" position or with the tractor running? Thanks again for your quick reply. Gary.

    JMOR    Posted 01-10-2021 at 11:35:48 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Polarizing Generator
  • All off, not running AND wire from gen Field to regulator disconnected, apply voltage to gen Field terminal , NOT to regulator terminal.

    Gary    Posted 01-11-2021 at 13:57:04 [URL] [DELETE]        [Reply] [Email]  
  • Re: Polarizing Generator
  • JMOR: Got it done. I was kind of expecting a spark or something when touched, but no fireworks. Tractor starts and runs well. Will battery discharge over time if it's not polarized correctly ? Thanks for everyone's help. Gary

    Tim Daley(MI)    Posted 01-11-2021 at 18:25:03 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Polarizing Generator
  • No. Polarity is how the generator functions, not anything to do with the battery. You can take measures to preserve your battery when not in use though. A battery can drain and it has no effect on the generator polarity. The battery is the 'heart' of the electrical system. A weak or dead battery is often the culprit in non-starting tractors/vehicles. The constant discharging and recharging of a battery will deplete its life span quickly. Bargain house units have a reputation of only giving 2 years or less of life so invest in a good brand (INTERSTATE, DEKA, DURACELL/East Penn) GP1 6V AG or GP25 or GP 35 12V battery. The best investment you can make to ensure a long battery lifespan is to buy and use a float charger. NOTE: A basic battery charger is not a 'float charger' it is a trickle charger and most have no automatic shut of which will overcharge the battery and kill it if left on unattended. Simply charging a battery does NOT mean it is good. It must maintain a full charge under load, meet the specific gravity specs by testing with an hydrometer or bench tester at a shop. When the vehicle is idle, i.e not running, you keep the float charger connected so it will maintain a full charge so it is 100% ready to go when you need it. Keep it connected if tractor is idle for 10 days or more. I just keep mine on every time when idle and use the DELATRN BATTERY TENDER units –reliable and guaranteed. Your local trusty starter/alternator/generator shop guy can bench test the battery, generator or alternator, ammeter, voltage regulator or cutout, ignition switch, Period preventative maintenance is the key. Check wiring and fan belt tension often. If your generator does not have a belt tensioning bracket, it will not keep the belt tight and thus will not keep the battery charged.

    FORD TRACTOR BATTERY INFO:


    BATTERY TENDER JR (6V) BY DELTRAN:


    Tim Daley(MI)

    JMOR    Posted 01-11-2021 at 16:21:25 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Polarizing Generator
  • When polarized wrong (reverse polarity) the usual arcing & sparking at VR contacts will generally weld or burn contacts. If correct, and polarization matches battery, then all should be good for charging. 641 has charge warning (idiot light) lamp & when VR cut out contacts close, it should extinguish. You can measure battery voltage before starting and again while running at speed & should see an increase of about a volt if charging.

    Gary    Posted 01-11-2021 at 17:20:54 [URL] [DELETE]        [Reply] [Email]  
  • Re: Polarizing Generator
  • Will do. Thanks again for your help. Gary

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