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.

[Capt Bruce]

Well Gang this must be the weekend for cut motor problems. Brushes I can deal with but not this.

I detached all the wire joints and removed the flexshaft locking screw. Then went to remove the motor end coupling of the flexshaft and the shaft came out in my hand while the coupling end stayed in place. At least it made the motor easy to slip out of the machine.

NOTE: This my second flexshaft assembly to lose the end fittings in less than six months. Is anyone else seeing this failure?

I began seperating the two halves of the motor shell and pieces parts of the shell rained down on my white workbench cover. The shaft end would not come apart on the horizontal split line but was cracked as shown below.

62564 62565 62566 62567

As evidenced by the dust and gunk between the already cracked shell in the bearing area this apparently happened some time ago and I've been running on plain old dumb luck leading up to this 200 hr stopped motor. I suspect pieces of the shell (see below) that came out of the opened shell halves may have jammed the cooling fan in its raceway and the motor just was not going to run again.

62568 62569 Just a bit of junk in there . . . .

The bearing end of the rotor is still trapped in the remains of the shell end and cannot be removed so I've left it in place for Tech Service to examine as I ask for a new motor. The portions of the bottom shell end surrounding the bearing look as though they were ultrasonically or chemically welded to the top half around the shaft connection end. I suspect all the parts only stayed in place because the motor was firmly mounted holding them aligned.

The comments in other posts lead me to suspect a bad motor can cause an X Termination board to go bad and vise versa so time to get a new pair all together and see if this puts it right. A bit more maintenance than I'd planned this weekend but you do what you've got to do.
Anyone else experience this failure? Thanks for listening to my sad bellyaching but my B and C machines have run remarkably until now and it just set me back.

[Digitalwoodshop]

I had 2 Cut Motors that experienced the End Bell crack and shatter.... It happened very early as seen by the dates.. BUT I had put on some serious carving time on the 2 machines..... I contacted LHR and at the Engineer (Raul? ) Requested I send them both to LHR for Evaluation... Due to a paperwork error on my part not keeping the Tracking Number they were never replaced... My Bad... Follow up with Customer Service... Provide a number get 2 motors.... My bad... no number...

But it is MY opinion that this is a result of shipping a unit WITH the Flex installed in the Cut Motor... It is just my opinion.... My early fear and as was Raul?, that I was seeing the beginning of a bunch of Motor Failures... He actually called ME.... "AL Who".... After I reported it to Customer Service... That is why He requested the Motors... It turns out that "I" was WRONG and it was just "Environmental" as in POOR Packing on MY PART... Sent one unit back to LHR for a Warranty Repair in 2007 and did not remove the Flex from the Cut Motor... And the 2nd I purchased USED and it came with the Flex Installed...

So rememeber... REMOVE the Flex for Shipping.. Based on the date on the pictures you can find the old post...

AL