Generator question

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Model T Ford Forum: Forum 2013: Generator question
Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Young in Mays Landing, NJ on Friday, August 09, 2013 - 06:37 pm:

With a fully assembled generator sitting on a bench and no cutout installed, should there be continuity between the output lug and the body of the generator?

I just finished repairing a break in the field coil. As l put it back together, l did multiple continuity tests to make sure that there were no shorts to ground as l went. The third brush clamping bolt is insulated and clear also. Once l got it all put back together, l put the meter to it and got a tone between the Lug and the barrel. Did l miss something?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Friday, August 09, 2013 - 07:04 pm:

If the brushes are down (against the commutator), then yes you will show continuity. You're reading the resistance of the field coils and part of the armature winding. Here's why.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Young in Mays Landing, NJ on Friday, August 09, 2013 - 10:44 pm:

Thanks Ken. The sketch is great and shows the path. At this point, should my next step be to hook jumper cables to it and see that she spins as a motor? l had nothing before.. ie, when l tried to power it, it didn't spin.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Friday, August 09, 2013 - 11:32 pm:

Did you disturb the neutral setting of the brush plate? That's the four small screws on the rear cover. If you didn't touch that, then hopefully it was set correctly to begin with. Yes, apply power to it and see if it motors. (All brushes down.)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Friday, August 09, 2013 - 11:42 pm:

I should mention that many refer to the brush plate setting as "neutral". In actuality, it's the brush lead setting.

You can check this setting while you have it on the bench. Lift the third brush spring and brush. Use the spring to wedge against the brush to hold it off the commutator. If you apply power the generator should NOT motor. If it does, the brush lead setting is incorrect.

Let me know if it does motor with the third brush up and we'll step through the setting.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Young in Mays Landing, NJ on Saturday, August 10, 2013 - 07:16 am:

l did remove the brush plate to check the insulator sheets. The sheet was fractured at the head of the third brush bolt, so l made a thin plastic disc from an oil jug and checked that that head does not protrude too far. So, resetting will be necessary and l have never done it. l will try to motor it this afternoon and let you know. Thank you for your help!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Saturday, August 10, 2013 - 09:00 am:

That's a common temporary fix but probably won't last long. the brush plate assembly gets hot enough to melt plastic. It will soften and the third brush will most likely drift from your setting. The third brush holder needs to be able slide in the slot without grounding. That's the reason the insulators extend past the brush holder slot. If you move your holder back and forth to set the current output, your disk could slide under the broken insulator and the small bolt will contact the holder. And a grounded third brush equals no output.

It's certainly yours to do as you wish but new insulators are available from the vendors. I suggest the fiberglass insulators made by Fun Projects. They will last a lifetime. The other type are fiber insulators like the original but aren't made correctly.

To set the brush lead (neutral setting);
1. Lift the third brush spring and brush off the commutator and wedge the spring against the brush to hold it up.

2. Loosen the four screws on the rear cover just enough to allow the entire brush plate to rotate with some drag. This will usually be one turn or less.

3. Ground the generator case and apply battery power to the generator post. Rotate the entire brush holder plate in both directions and note that the armature motors clockwise then counter clockwise with the movement.

4. Rotate the brush plate to a location where the motoring STOPS and just begins to turn clockwise. (As viewed from the gear end.) It should NOT motor.

5. Tighten the four screws on the back and verify that the generator does NOT motor. If it does, return to step 2 above but snug the screws a little for more drag.

6. Return the third brush and spring to their running position.

The brush lead is now set and should never be moved unless the brush holders are replaced or the armature changed in any way.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Young in Mays Landing, NJ on Saturday, August 10, 2013 - 05:27 pm:

Since the plastic disc may melt, l got a decent brush plate out of another generator and will continue this project tomorrow afternoon.

Generators seem to be a pretty hot topic lately!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Saturday, August 10, 2013 - 06:51 pm:

I highly recommend the fiberglass insulators. I got mine from Langs or Snyder's, but someone said John Regan makes them. If that's so, that explains the good quality.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Young in Mays Landing, NJ on Sunday, August 11, 2013 - 03:10 pm:

Well, l put the other brush plate in and did the "lead setting" as described and then motored it. She spun great! Next, it got installed with Regan's VR and the third brush set per the instruction sheet.

All is now good, charging well and the headlights look good again. However, l am going to order in the fiberglass plate insulators and rehab my spare plate, because the one that's in the generator at this time is marginal at best. Thanks Ken!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Sunday, August 11, 2013 - 03:28 pm:

You're welcome Dave. Glad that worked for you.

T-on!


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