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Thread: Blackface Exciter coils

  1. #1
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    Blackface Exciter coils

    I have a 1980 Blackface that according to specs, the exciter coils are made of aluminum, they ohm at 130. My question is, has anyone had the exciter housing get warm and have the voltage drop off from 118 to 110 volts at the outlet plug? Also the lead studs start out at 94 volts and stop dropping at around 86.5 volts after running the engine at high idle for 35-40 mins, BUT even though since I finished seating the new brushes in, it welds nice and smooth with 6010 and 7018. My other Blackface machines by comparison, hasn't done this. Could this be a sign of the exciter coils going out? Can't recall ever having this happen on other later Blackface machines.
    Last edited by BYW200; 07-21-2020 at 07:16 PM.
    SA 200s : 1944 1945 1963 1965 1969 1980
    1981 SA 250 D3.152 DC only
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  2. #2
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    Re: Blackface Exciter coils

    OCV and Other Specs.pdf

    The SA200 Service Manual actually points out an expected and normal drop in voltage as the unit warms. The time frame of 1 hour or more of continuous running is pointed out as required to see a stop of voltage drop.

    Your figures indicate to me that perhaps the engine RPM is a little low as well.
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  3. #3
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    Re: Blackface Exciter coils

    Hi Duane, I forgot to mention the High idle is close to 1600 rpms no load, just the way it is now, using my Stewart Warner gauge at the end of the armature shaft, unless my gauge is wrong. I haven't had the Exciter coils get that warm where the housing got almost hot. I did have the Rheostat all the way up for about 40 minutes.
    SA 200s : 1944 1945 1963 1965 1969 1980
    1981 SA 250 D3.152 DC only
    2004 Ranger 10,000
    Lincoln Pro Mig 135
    Miller Load Bank
    Hobart GPB 258 Pipeliner
    Hobart GPB 261 Mainliner
    Hobart Airforce 250
    Everlast PA 200st

  4. #4
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    Re: Blackface Exciter coils

    Mmmm. Have to say I've never seen one get so warm it's "almost hot". I trust all the cooling fan blades are in place and no restriction to air flow.

    Is the main brush cover band in place? If not, air flow across the exciter coils/armature will be limited or none.
    MM200 w/Spoolmatic 1
    Syncrowave 180SD
    Bobcat 225G Plus - LP/NG
    MUTT Suitcase Wirefeeder
    WC-1S/Spoolmatic 1
    HF-251D-1
    PakMaster 100XL
    '68 Red Face Code #6633 project
    Star Jet 21-110

    Save Second Base!

  5. #5
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    Re: Blackface Exciter coils

    Yes, all cooling fins are in place. I was running it without the band cover on, I didn't think much of it. I'll see how it does after putting the band cover on and report back. Could explain why my voltage is dropping off.
    SA 200s : 1944 1945 1963 1965 1969 1980
    1981 SA 250 D3.152 DC only
    2004 Ranger 10,000
    Lincoln Pro Mig 135
    Miller Load Bank
    Hobart GPB 258 Pipeliner
    Hobart GPB 261 Mainliner
    Hobart Airforce 250
    Everlast PA 200st

  6. #6
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    Re: Blackface Exciter coils

    Here's my update. After installing the cover, the Exciter housing ran alot cooler, and the voltage at outlet plug had a stable voltage of around 116 after running for over an hour, sometimes it's the little things that get you over the bigger things. I went ahead and load banked it, and I did some adjusting of the rack to bring the volts down to within factory specs, here is a pic of the results.
    Attached Images Attached Images  
    Last edited by BYW200; 07-26-2020 at 08:38 PM.
    SA 200s : 1944 1945 1963 1965 1969 1980
    1981 SA 250 D3.152 DC only
    2004 Ranger 10,000
    Lincoln Pro Mig 135
    Miller Load Bank
    Hobart GPB 258 Pipeliner
    Hobart GPB 261 Mainliner
    Hobart Airforce 250
    Everlast PA 200st

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