Motor sounds "gritty"

[KeystoneChuck]

I had a problem with my last carving. It was a 1hr 45 min carve, in the last two minutes of the carve I smelled something funny and the bit was not spinning as fast and clean sounding as before. I checked my flex shaft, seems fine then I went to run another small carve just to see if it was me and the bit was turning slow and was "twitchy" (sorry for this technical words; I feel like I am the transmission mechanic Lol). I stopped the project performed the cut motor test with no bit. Same results. Took the flex shaft out and ran just the motor and same "gritty" noise and I seen a spark shoot out of the dust port (no bag was on). Any ideas before I start the nasty. I would hate to get elbow deep in this and find out it was a common problem and you just have to turn a screw or something. Machine has 50 hrs 47 min on motor time and 76 hrs total machine time. If this makes a difference this is the third "long" over 1hr. carve for me I have done. All my other carves/signs are under 50minutes.

[bergerud]

Assuming no warranty, I would say the motor has to come apart. A new one to me. A bad bearing or armature rubbing? Melted casing? Let us know what you find.

[lynnfrwd]

Check x-termination board to make sure there are no burn marks.

[KeystoneChuck]

I have an electric motor repair company about 10 minutes from my shop. I take all my regular electric motors (band saw/table raw/drill press) when they need service. I know I have to ask them if they could even work on it for me. But is there anything I should be aware of when I take motor out when I show them? Is there ant sensors or switched to be concerned about. To me real quick it looked like an over sized dremel motor.

[KeystoneChuck]

Well I got the motor out and I definitely see the problem. The back of the motor (opposite of the flex shaft) has melted and cracked. I was in a good mood till I seen that. I will post pictures when I put them on my computer. I know stuff wears out but the machine has 50 hrs & 47 minutes of cutting time on it. And the only wood I have cut in it are pine and cedar, no hardwoods or plastics. I am wondering if this was a problem from the start. All but 3 of my carvings have been under 50 minutes the other three which I have done just last week have been 1 hr 45 min. Which going by some of the carve stories on here is not much at all. I'll let you guys know what the electric motor guys say.

[KeystoneChuck]

Here are pics of motor straight out of machine. I went down to my electric motor guy and he said the motor is "toast". He said even if they sold me the motor housing which he said they probably woudn't he would spend more on labor than what its worth. Thats a lot from him because we use to get our motors done up at Crowder Motors in Allentown, PA and then we found this guy by mistake one day and he is 10min, from our shop. And most importantly he is super fast on turn arounds and 1/3 the price we were paying to Crowder which typical turn aroung time was three weeks.

[TerryT]

Wow, that is pretty ugly. I think you need more than just the plastic case replaced.

[bergerud]

If you saw sparks out of the exhaust, the armature was scraping on the field magnets. That is toast! Do not tell me you had a 50 hour warranty!

[KeystoneChuck]

I am a firm non-believer in warranties. Have the same outlook on warrabties as Tommy Boy...Tommy Callahan III: How do you know the guaranteed fairy isn't some crazy glue sniffer. He sneaks into your house once and that's all it takes. Next thing you know, there is money missing off your dresser and your daughter is knocked up! I've seen it a hundred times. LOL Love that movie! My luck I would buy a 50hr warranty and it goes at 50hrs 47 min. And like my brother just told me, that would be my luck. If it weren't for bad luck I'd have no luck at all. He was floored when I told him it came with a 10hr warranty. He acted like Uncle Eddy in Vegas Vacation when Clark told him how much money he lost. Had same thing with my 2006 Toyota truck, had 60,000 mile warranty and it crapped out on the side of the road at 60,167. Like the saying goes "This would be funny if it wasn't happening to me". I am hoping that LHR will at least knock off $40 for the core charge taking the $185 motor to $145. Fingers crossed. Quick question to bergerud, what would make the armature scape the field magnets, besides the obvious answer of repositining of the parts. HaHa I just wanted to know if there is something I could do to prevent this from happening again.

[bergerud]

I would say just the shifting of parts. The scraping would have been caused by the broken casing letting the bearing move. Why the casing broke, who knows.