exhaust fans

[crotech]

recently found 3/4 hp motor with bad cap. got going. than found another with bad cap. same motor same age of motor, they were both replaced w/i 4 month. im wondering if the wrong size motors were used. fan is a vent pak style serving a chemical hood, belt driven.

[gbfromsd]

were the motors amped out ok? do they operate in extreme conditions?
Are the belts usually too tight, properly aligned? These are the chief reasons a motor dies
prematurely.

[madhat]

Probably the wrong motors. Motors for PRVs have an 1.15 to 1.25 service factor, some have fans inside the motor housing, very few have run capacitors. If you can tell me the Brand and M/n, I maybe able to come up with the correct motor ID and frame number.

[John Culpepper]

Had similar problem on 2 of my downblast units, burned out the cap but not the motor. Turned out to be unit shaft bearings (units were of similar age) repaced blower shaft bearings and all good.