"Ken Knecht" wrote in message
...
I put a new two-speed blower motor in my evaporative cooler yesterday.
The motor makes a pretty loud buzzing/humming noise. It does it with belt
off so it's the motor, not the blower. It's not the water pump. Checked
current draw with clamp-on meter and it's slightly (0.1 A or so) below or
equal to rated current marked on motor with the belt on. It's louder on
low speed - maybe because blower is quieter?). Other than the noise it
seems to work ok. I ran it for about 9 hours yesterday at low speed
(which I normally use) with no problems.

Just ignore the noise? I can live with it if it isn't trying to tell me
it's in trouble.

TIA.

Ken

What you are experiencing may be a harmonic effect. With the motor NOT
connected to the belt, all the vibration is transferred to the metal
framework with no dampening effect from the rubber belt.

I'd try it with the belt. If there's still a loud hum, then check out the
electrical end.

Mine works perfectly, and has a lot of hum and noise. I think it's just the
nature of the beast. You may also get some thick grommets with which to
mount the motor that may take out some of the hum if yours is mounted metal
on metal. I'd try the cheap fixes before digging too deep.

Sometimes the problems are the simplest and most obvious little things.

Steve, an old swamp cooler veteran