About 6 weeks ago, I purchased a Hallmark Industries MA0515E AC Motor, 1.5 hp, 1725 RPM, 3PH/60 hz from Amazon. Took me about a month to build the grinder, but now that I'm dialing it in......I'm noticing a noise from the motor that seems to indicate some internal interference at certain motor speeds.
The motor is being driven by a VFD. At speeds below ~500 RPM (18 hz), there is no noise. When I get to ~575 RPM (20hz), there is a clicking/scraping noise that increases in amplitude until about 1725 RPM (60 hz - the nominal motor speed). Above 60hz, it's very smooth and quiet. I have the upper frequency limit on the VFD currently set to 80 hz, (~2150 RPM), but plan to enable it up to 120 hz at some point).
The video I attached isn't playing too well on my computer (perhaps too large?). You can also view it at:
https://1drv.ms/v/s!AmQC9yd8k4EK9N5Uv1oeuMdMW2d25w?e=mjcAnN
I've temporarily removed the fan housing and the fan (it's a TEFC motor) and did not note any change in the noise.
Would I be crazy to undo the 4 very long bolts and attempt to remove the rotating portions of the motor. It seems to me that there must be something that's scraping just a tiny bit that I could file or bend back into a non-interference condition. I can attempt to get the motor addressed under warranty, but that will certainly be a hassle (I think I tossed all the packaging).
RR
The motor is being driven by a VFD. At speeds below ~500 RPM (18 hz), there is no noise. When I get to ~575 RPM (20hz), there is a clicking/scraping noise that increases in amplitude until about 1725 RPM (60 hz - the nominal motor speed). Above 60hz, it's very smooth and quiet. I have the upper frequency limit on the VFD currently set to 80 hz, (~2150 RPM), but plan to enable it up to 120 hz at some point).
The video I attached isn't playing too well on my computer (perhaps too large?). You can also view it at:
https://1drv.ms/v/s!AmQC9yd8k4EK9N5Uv1oeuMdMW2d25w?e=mjcAnN
I've temporarily removed the fan housing and the fan (it's a TEFC motor) and did not note any change in the noise.
Would I be crazy to undo the 4 very long bolts and attempt to remove the rotating portions of the motor. It seems to me that there must be something that's scraping just a tiny bit that I could file or bend back into a non-interference condition. I can attempt to get the motor addressed under warranty, but that will certainly be a hassle (I think I tossed all the packaging).
RR