I've seen a number of older exhaust fans that start very slowly. Turn them on,
they barely turn for up to several minutes, then finally speed up fairly quickly
to normal operating speed. Can anyone suggest why this happens, and a way to fix
them to operate properly?
Sure, that will fix it but having spent a large part of my work life
sorting that sorta stuff I can tell you a lot of the time the motor runs
away with no attention until it stops or exhibits the symptoms described.
The manufacturers provide ports to apply periodic lubrication which are
by and large ignored by the average punter. A slow start is almost
certain to be an underlubricated bearing or one that has been worn out
by long usage or underlubrication, usually both.
Nowadays the cost of professional maintenance can exceed the cost of a
replacement (assuming you DIY) so there ya go. For me there is nothing
to lose with trying a squirt of light oil on the bearings before
spending ya moola :-)
Cheers ............ Rheilly P
I've seen this a number of times with bathroom exhaust fans. After removing
the internal parts and cleaning them thoroughly, performance on many of them
improves. Gunk tends to build up on the fan blade which I surmise causes it
to be heavier than the little motor was designed for. If not then I replace
the motor and blade or install a new and improved (Panasonic) bath fan.
I assume you are talking about the motors without a capacitor and a start
terminal. These motors develop weak torque until reaching full speed. The
lubrication gums and the motor spins slow for awhile. It is best to
dissasemble the motor, degrease the bearings and apply a light oil (like 3
and 1 motor oil).
The folks I have worked with tell me that three in one is a poor choice for
motors. It (three in one) dries out rapidly. Same with WD-40. The good
choice is ND-30 motor oil, or zoom spout turbine oil. The gas mix oil for
two strokes is supposed to be good, also.
Cleaning the blade sounds like a wise action, also.
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