Product Manual

Hertz / Frequency
In North America 60 hz (cycles) is the common power source. However,
most of the rest of the world is supplied with 50 hz power.
Horsepower
Exactly 746 watts of electrical power will produce 1 HP if a motor could
operate at 100% efficiency, but of course no motor is 100% efficient. A 1
HP motor operating at 84% efficiency will have a total watt consumption
of 888 watts. This amounts to 746 watts of usable power and 142 watts
loss due to heat, friction, etc. (888 x .84 = 746 = 1 HP).
Horsepower can also be calculated if torque is known, using one of
these formulas:
Torque (lb-ft) x RPM
HP =
5,250
Torque (oz-ft) x RPM
HP =
84,000
Torque (lb-in) x RPM
HP =
63,000
Speeds
The approximate RPM at rated load for small and medium motors
operating at 60 hz and 50 hz at rated volts are as follows:
60 hz 50 hz Synch. Speed
2 Pole 3450 2850 3600
4 Pole 1725 1425 1800
6 Pole 1140 950 1200
8 Pole 850 700 900
Synchronous speed (no-load) can be determined by this formula:
Frequency (Hertz) x 120
Number of Poles
-36-