I have a situation where a motor is rated at 167 amps and we are pulling 205 amps and yet not tripping the overloads or the 200 amp fuses in the disconnect. We have had trouble with one leg heating and have retightened the lugs and still having trouble with it heating. How do I size my new circuit breaker which we are putting in in place of the fuses and the wiring since I am over full load amps of the motor?
sizing for a motor that is running over FLA.
- Thread starter ken Horn
- Start date
- Status
- Location
- Massachusetts
ken Horn said:
How confident are you in the meter readings?
Is it a true RMS meter?
Have you checked it against other meters?
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
ken Horn said:
Instead of replacing the fuses and conductors, have you considered replacing the motor?
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Most motors will have a service factor of 15 %, thats about 16 amps in your case, but going into the SF cuts down motor life due to heat.
The load is what controls the amperage on the motor. Whats going on with the load? Bad bearing?
What type and class of overloads do you have?
And how are you measuring the current? has your meter been calibrated?
The load is what controls the amperage on the motor. Whats going on with the load? Bad bearing?
What type and class of overloads do you have?
And how are you measuring the current? has your meter been calibrated?
- Status