R Duty Rating
Motors are classified according to the length
of time expected to operate under full load.
C The motor may be rated as either:
1. Continuous Duty
2. Intermittent Duty
Continuous Duty Motors
Continuous duty rated motors are rated to be
run continuously without any damage or
reduction in life of the motor.
C General purpose motors will
normally be rated for continuous duty.
Intermittent Duty Motors
Intermittent duty motors are rated to be run continuously only for short time periods and then must
be allowed to stop and cool before restarting.
C It is usually possible to reduce
the size, weight, and cost of a
motor by purchasing an
intermittent duty motor.
C Intermittent duty motors are
available with maximum
operating times of 5, 15, 30, or
60 minute duties or times.
C These motors are sometimes
used on devices like garbage
disposals or air compressors
where the motor operates for a
short period and shuts off after
the job is accomplished and will
not be needed for an extended
time period.