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Anorak Bob
30th Oct 2017, 08:48 PM
Hello All,

The motor driving my lathe has developed a cyclic clicking noise, The motor is a 750 watt Brooks Crompton single phase, capacitor start, capacitor run model and has run flawlessly for the past 15 years or so

I will pop the end plates off for a squizz probably tomorrow. Any suggestions as to what might be amiss?

Bob.

Michael G
30th Oct 2017, 09:29 PM
Depending on whether the clicking is happening quickly or slowly, check the belt as there may be a hard spot or embedded swarf causing the noise.

Michael

BobL
30th Oct 2017, 10:17 PM
Change the gears and see whether the click frequency changes, If it does it won't be the motor or the primary belt/pulley but something else in the drive train

Retromilling
31st Oct 2017, 03:27 PM
I would take the drive belt /s off first and then run the motor . See if it stops . If it don't put a screwdriver handle to your ear and the blade end on the motor in different places as it's running . If it stops clicking place a load on the motor pully with a piece of wood as a brake lever . If it starts again it could be a bearing . If it seems all normal it must be further along the drive chain . If it's inside the motor it could be a switch system some have at the fan end of the motor or a bearing problem .

Anorak Bob
31st Oct 2017, 09:12 PM
I realise now that the thread title should have been "Beltless Motor Noise".

The noise seemed to be emanating from the motor's centrifugal switch mechanism but on disassembly I could find no apparent problem. The bearings were not as smooth running as they should be so I replaced them with a fresh pair of shielded Nacchis. Some of the bindings on the exposed windings had broken so I re-tethered them with bootmaker's linen thread and 5 minute Araldite. On reassembly I noticed that the rotor could move a few millimeters axially in the end caps. I have another Brooks Crompton motor, a 1/3hp version that has unventilated end caps but other than the lack of holes, look the same as those on the 1 horse motor. Removing the rear end cap revealed a wave and a spacer washer behind the bearing. For some unknown reason those parts were absent in the lathe's motor. The 1/3 hp motor became a donor.

Assembled yet again and remounted on the lathe with the pulley and belt in place, the motor runs smoothly and quietly.

Thank you all for your suggestions.

Bob.

Retromilling
31st Oct 2017, 09:58 PM
That's good , those centrifugal switches are a source of problems .