I have a Craftex CX400 2HP dust collector. The DC is basically brand new, although I bought it 2nd hand from someone so I really just can't return it. It's making a whistling sound just as the motor is stopping, after you hear the 'brake' click on - within the last 2-4 seconds just as the motor comes to a complete stop. Like many others I've seen do this, I changed it to a 2 stage with a Super Dust Deputy XL and wall-mounted it (the impeller horizontally and motor vertically). I have been installing my DC (with duct work) over the last couple weeks and got it running a week ago and it did not make this noise until the humid temps started in the last two days or so.
It seems to be coming from the end with the fan, so I took off the end cap and the fan (just a set screw) and also removed the dust cap which is a metal plate that has a rubber seal around the motor shaft. I turned the shaft by hand and didn't feel any play or hear any noise from bearings.
I did not feel comfortable starting the motor with the metal plate and rubber seal off, but if someone thinks that'd be okay for testing I could try it. Again the motor 'brake' would be exposed. At least I think it's the brake mechanism.
I put some graphite spray on the shaft and then slid the rubber seal down and replaced the other parts. The noise seemed to stop at first but then it came back.
Would white lithium grease or another grease be better?
I had started the motor many times before the sound started so I'm hoping its just this seal and lubrication is the answer.
Thanks.