Another C Unit Cut Motor slowed and then quit running

[Capt Bruce]

Team,

I swear these machines have a calendar function built in to quit working on Friday night of three day weekends. 200 Hrs 8 min on the cut motor.

Several other C Unit machine owners have noted recently their new machines' cut motor slowed down and then just quit. Like them I have run all the appropriate tests (Cut motor test shows it is running when it is not) and no cover switch faults show up. No spin up during bit loading. Cover switch tests correctly.

Removed the motor and inspected the brushes which are still 1/2 original length or more. Checked down below and the suspect board in all the other threads I've reviewed, is clean and bright at every connection and solder joint. Checked every other wire connection down there and the balance of the boards with no suspicious burn marks or loose connections or broken joints.

I had the motor out to check its brushes but did not crack open the motor shell. It will come completely out next time for a 120 V direct test. I guess that's next to see if I need to purchase another while down in Houston in two weeks. I'd appreciate any other advice while I have the CW down and out and cannot carve for now before Tuesday. Thanks in advance.

[chief2007]

Could be that the switch is not making contact with the tab of the cover and not therefore not closing the circuit.

Could also be a wire is loose or burnt inside the cut motor itself.

Still could be a faulty X termination board as well.

[henry1]

Open the motor could be the wire to the brush have disconnected I had one like that

[Digitalwoodshop]

Do you have another set of brushes..... Could be.... The guy in China making the brushes is getting a little cheap on the Copper Wire that runs inside the SPRING of the brush and it is acting as a DOG CHAIN and not letting the brush reach the commutator....

Another in a long series of WAG's from AL... Wild AL Guesses....

AL

[Capt Bruce]

Good suggestions all Gentlemen. I guess I'll go cut motor diving in the morning when I can find my continuity tester and then rig the cleaned motor for a direct 120 Volt run.
Unfortunately I sold my spare set of brushes to a customer in a bind and was going to pick up more down in Houston next month. Wish me luck and have a good Memorial Day.

[jbrunot01]

Hi Bruce -

Jeff here - over in Marietta.

I've had my machine for 6 mo now. I've been pumping out lots of work. Had a gteat weekend up at the Marietta Square Artists Market. Sold lots of work and took lots of orders. My machine did the same thing last night. Motor startrd slowing down then quit all together.

[Capt Bruce]

Hi again Jeff,
As noted in the parallel post on this problem showing up in newer C Machines let's share what we discover. Opening my motor today to take a look at internal connections.

[liquidguitars]

I like to blame sun spots but i would go with inspection...

[jbrunot01]

I foung one brush was bad / melted... It was the one on the bottom of motor. The side w/ the rectangular air port. Not the side with the RPM Sensor board.

[SharonB]

Good morning everyone. My motor didn't act up or quit but was getting close to 250 hours so inspected the cut motor brushes and the top one came apart in my hand as I removed it for inspection. The brushes were only about 1/3 (if that) gone on both brushes. Replaced them both. The wire that connected the parts together had come loose from the top "plate." Just a accident waiting to happen.