T7 noise

[joel]

I just assembled my new T7 and have a question about a disconcerting sound.

As the wheels revolve, the normal "running hum" is not a steady sound. With each revolution, it makes a deep "wha... wha... wha" sound as if something is bent or out of balance. It's not a scraping sound. I have other grinders in my shop that have a normal smooth running, electric motor hum which is the sound I would expect from a premium priced product as the Tormek. The grinding wheel appears to be turning within specs.

Is this normal? What is causing this? Does yours make this same sound? I'm hesitant to use it until I'm certain that all T7s produce this sound. 

Thanks for your kind assistance.

[Herman Trivilino]

Sounds like the water trough vibrating.  Hold it or remove it and see if the noise goes away.

[joel]

Herman, Thanks for the suggestion but the sound does not disappear with the water trough removed. However, in the process of feeling around to find the culprit, I discovered that if I pivot the motor up and away from the front of the housing, the sound goes away. So, I stuffed a rolled-up Scotch Brite pad in there to hold the motor up about 1/2" further, and it's now quiet. But, I can feel the motor move very slightly up and down as it runs – like something is out-of-round.

Is there a way to adjust the motor into this elevated position that isn't such a Mickey Mouse solution? Is it OK to run it with the motor in a different position? I certainly don't want to cause any future problems. And anyway, I don't think the customer should have to resort to a "work-around" on a new piece of premium equipment.

Jeff, if you see this post, I'd really appreciate your input and an "official" Tormek opinion on this?  Thanks!!

[Jeff Farris]

The rhythm comes from the point on the drive wheel where the motor was resting previously. Where ever the motor shaft is on the drive tire when the machine comes to a full stop will develop a slight dimple in the tire. That dimple will cause a change in the motor sound, but not in the speed or power delivery of the system. As the machine runs, the dimple will lose its "memory" and the noise will dissipate and then disappear.

Do not place anything in the machine that levers against the motor. The motor must be allowed to swing freely on its pivot for the system to have full power.

[joel]

Jeff, Thanks for responding. I tested your "dimple" theory by letting the machine run for 13 minutes and the noise never dissipated. In fact, when I applied very slight pressure with the palm of my hand on the top of the leather wheel to simulate the honing process, and the noise got much louder.

[Jeff Farris]

That's because the motor draws into the tire as load is applied. Like any other electrical machine, it makes more noise under load than it does running unloaded.