10ee acting funny

Jaymce · Jul 13, 2019

Fired it up today and spindle drive seems to be engaging and disengaging. Any one seen this before?

Tapatalk Cloud - Downlaoad File 20190713_132108.mp4

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labeeman · Jul 13, 2019

What Kind of drive do you Have?

Jaymce · Jul 13, 2019

labeeman said:
What Kind of drive do you Have?

1942 machine it all seems to be original.

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labeeman · Jul 13, 2019

Check your brushes on the MG, exciter and the motor.

Cal Haines · Jul 13, 2019

I think I know what's going on, but I need to see a photo of the inside of your DC control panel. (It's the big box in the headstock end of the base, next to the spindle motor.)

Do you see sparking coming from the spindle motor's commutator?

Are any of the relays in the DC control panel cycling on and off in time with the pulsing of the spindle?

Cal

donie · Jul 13, 2019

My MG set is the last version, but, if the earlier exciter uses a pair of, or split brushes, after time, they will wear a ridge down the middle of the commutator, that can be seen by the bright line in the photo.
The ridge, when too tall, will tend to push the brushes apart and stick in the holders, and causing low voltage resulting in surging.
In the photo Iam using an Ideal Electric commutator dressing stone that I glued to a stick, to remove the ridge, and smooth the commutator.
May be something to have a look at.

Jaymce · Jul 13, 2019

Cal Haines said:
I think I know what's going on, but I need to see a photo of the inside of your DC control panel. (It's the big box in the headstock end of the base, next to the spindle motor.)

Do you see sparking coming from the spindle motor's commutator?

Are any of the relays in the DC control panel cycling on and off in time with the pulsing of the spindle?

Cal

I have left for the day but will check in the AM.

I believe that I was hearing something electrical cycling but can get better info tomorrow.

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Jaymce · Jul 13, 2019

donie said:
My MG set is the last version, but, if the earlier exciter uses a pair of, or split brushes, after time, they will wear a ridge down the middle of the commutator, that can be seen by the bright line in the photo.
The ridge, when too tall, will tend to push the brushes apart and stick in the holders, and causing low voltage resulting in surging.
In the photo Iam using an Ideal Electric commutator dressing stone that I glued to a stick, to remove the ridge, and smooth the commutator.
May be something to have a look at.

I will check it out. That is on the right side when facing the machine?

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9100 · Jul 13, 2019

I have seen more sticking brushes than any other problem. Much of the time a therapeutic wiggle is all that is needed. Donie, you must put a lot of miles on your lathes. I haven't seen the ridge problem or any appreciable commutator wear on machines in a job shop with constant use. One modular is the lathe of choice for one machinist. The owner gets upset when it has problems because that machinist on that lathe is a money machine. The fellow can run any machine in the shop, but with three Moris, and a Hwacheon, a small Harrison and an MG 10EE besides the modular, that is his choice and the way he turns out work, we try to keep him happy.

Bill

donie · Jul 14, 2019

I estimate I have to dress the commutator about every 3000 hours.

Jaymce · Jul 14, 2019

Sorry guys. Did not get a chance to look today as I am falling behind in work. Hopefully tomorrow will be better.
Thanks for all the suggestions so far.

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TheOldCar · Jul 14, 2019

After my exciter suddenly needing a flash every 2 months, I removed the armature and turned the commutator bars down past some burn/flash gouges. Then carefully cut the mica grooves down with jeweler files, chamfering the corners just a bit. The mica had been sitting higher the bars! I don't remember the abrasive I used for final turned finish of the bars (googled it, but made sure it wasn't crap sandpaper that would embed into the copper. I also made sure to clean away dust afterward. Before this I had dressed the commutator while still inside the exciter, but that finally wasn't enough. Even new brushes had worn at an alarming rate! I also checked, adjusted, and checked again that the brushes had free play.

9100 · Jul 14, 2019

TheOldCar said:
After my exciter suddenly needing a flash every 2 months, I removed the armature and turned the commutator bars down past some burn/flash gouges. Then carefully cut the mica grooves down with jeweler files, chamfering the corners just a bit. The mica had been sitting higher the bars! I don't remember the abrasive I used for final turned finish of the bars (googled it, but made sure it wasn't crap sandpaper that would embed into the copper. I also made sure to clean away dust afterward. Before this I had dressed the commutator while still inside the exciter, but that finally wasn't enough. Even new brushes had worn at an alarming rate! I also checked, adjusted, and checked again that the brushes had free play.

The professionals use what looks like a miniature slitting saw, perhaps 3/8" diameter so they can cut a groove close to the larger part of the commutator where the wires attach. Then sand the burrs with 600 grit wet or dry. I don't do enough commutators to invest in professional equipment so I grind the set off a hacksaw blade on the end where the teeth are pointing toward the center of the blade so it cuts on pull. I cut the slots and deburr with 600 grit, blow the dust out and tape a strip of 400 grit around the commutator with the grit out. I install the armature in the motor with the brushes and form them by rocking the armature back and forth. Remove the strip, blow the dust out, and you are ready to go. Forget about embedment. Its an old wives tale that won't go away. Hans Fischer, the honing guru at Sunnen did tests. He knew a lot more about the subject than either of us and had all the equipment. When I asked him about it, his response was "Oh, that again." He found that you had to press the grit into the metal almost deliberately. Grit rolling across a surface in hand sanding simply will not have enough pressure to make it stick. Forget it. You probably would be best to mount the armature in a lathe and wrap the sandpaper with a thumb and forefinger applying pressure, the purpose being to round the corners of the slots slightly (like a couple of thousandths) to keep them from cutting on the brushes.

Bill

TheOldCar · Jul 14, 2019

Thanks for that post, I totally feel for the embedment scare, which led me to never divulging what abrasive I used. :dunce:

After it was all back together, I made sure to seat the brushes with sandpaper as you said.

Jaymce · Jul 17, 2019

So I finally got around to digging a little further on this today.

Motor on the right u see the tail stock fires and runs consistently.
Pulled the covers and noticed the magnetic switches? Kicking in and out. Both directions. They were very dirty so I pulled them apart and cleaned them. Put it back together and the lathe is still behaving the same. Spindle kicks in and out.Tapatalk Cloud - Downlaoad File 20190717_164140.mp4

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Jaymce · Jul 17, 2019

labeeman said:
Check your brushes on the MG, exciter and the motor.

Seem a little worn but visible and seem to move freely.

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Jaymce · Jul 17, 2019

Cal Haines said:
I think I know what's going on, but I need to see a photo of the inside of your DC control panel. (It's the big box in the headstock end of the base, next to the spindle motor.)

Do you see sparking coming from the spindle motor's commutator?

Are any of the relays in the DC control panel cycling on and off in time with the pulsing of the spindle?

Cal

Pic attached

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Jaymce · Jul 17, 2019

donie said:
My MG set is the last version, but, if the earlier exciter uses a pair of, or split brushes, after time, they will wear a ridge down the middle of the commutator, that can be seen by the bright line in the photo.
The ridge, when too tall, will tend to push the brushes apart and stick in the holders, and causing low voltage resulting in surging.
In the photo Iam using an Ideal Electric commutator dressing stone that I glued to a stick, to remove the ridge, and smooth the commutator.
May be something to have a look at.

It does not have split brushes.

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Jaymce · Jul 17, 2019

thermite said:
Still a good idea to see that they are in good order.

An erratic FA relay seems a better fit to the symptom, even so.

The brushes seem to be ok.

Forgive my ignorance "FA relay"

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Cal Haines · Jul 17, 2019

Jaymce said:
Pic attached

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It looks like the DC control panel has been replaced at some point. That's the type of panel that was used on square-dial and WiaD 10EEs. What you have is a known problem with "Resistor B-E" in the upper-right corner of the panel. $30 worth of parts and you'll be back in business.

See this post: Start up problem with m/G machine?

If you need to use the machine while you're waiting for parts to arrive, you can jumper around resistor B-E, just be careful not to plug reverse the machine, as the jumper will disable the anti-plugging circuit.

Cal

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