AboutWill Expertise Three phase electic motors, controls and related problems or failures, three phase motor installation issues, performance issues, connections, data and duty cycle information. All other electic motors. Specialty motors, repair concerns, performance concerns, obsolete motors and solutions. Other specialty equipment issues. Lost nameplate data and identification, lost connection data.
Also DC motors of all types.
See my profile under Home/electrical at this site
Experience 30 plus years in the electrical motor and apparatus repair industry. VP level management of repair facilities, current owner of my own specialty repair and consulting firm.
Organizations EASA, IBEW [retired], other specialty organizatons, Lubrication, Vibration EDI, Triboelectric Councils
Publications Currently fielding concerns at this site under "Home Electrical"
Education/Credentials 4 year technical, College level specific courses, EASA repair courses, vibration analysis electronic and electrical trade school.
Expert: Will Date: 6/1/2008 Subject: Dayton single phase 120/240 VAC motor
Question It has a rated 30 minute duty cycle. Does that mean 30 minutes run, 30 minutes off? Or 15 min. run / 15 min. off? Could you please elabourate?
Also, we suspect the cap is bad - motor won't self-start but will run once "hand turned". The single capacitor is rated at 230 MFD/125 VAC...thus I'm assuming we have a simple "capacitor-start induction motor"? There's no centrifugal switch that I know of. Very little info remains on nameplate.
Thanks
Answer 30 minute duty is per type of motor:
Motors are rated by the output power they can produce over a given time period without overheating. These ratings are on the motor nameplate. Manufacturers build motors with different duty cycles to match the three load categories. Duty cycle is the ratio of time the motor produces rated power divided by the total elapsed time. Motors with less than 100% duty cycle must turn off for an amount of time specified by the duty cycle to cool-down after operating. A motor with a 50% duty cycle must stay off for the same amount of time it has been on. Motors with less than 100% duty cycle also have a maximum run-time limit such as 30 min. A 50% duty cycle motor with a 30 min run time means the motor can operate at its rated output for 30 min. Then it must stay off at least 30 min — for 60 min total time — before running again.
With a cap and no switch you have either a psc motor [permanent split cap] or you could have a split phase cap motor, either way you are probably correct, bad cap, maybe bad start winding but if it runs with a push and at the correct current, bad cap, get an exact replacement and you should be fine.
