Custom Motors Technical Information

Typical Maximum Horsepower by Enclosure Type (Single phase ratings are slightly lower)

FramePolesOpen
Dripproof
TEFCTENVExplosion ProofIn Oil
(or intermittent duty)
36 Frame
(3.75" diameter)
3450 1/3 1/4 1/6 1
1725 1/4 1/6 1/8 1/2
48 Frame
(5.50" diameter)
3450 2.5 1 1/2 1 4
1725 1 3/4 1/3 3/4 2
1140 3/4 1/2 1/3 1/3 1
56 Frame
(6.12" diameter)
3450 5 3 1.5 3 10
1725 3 2 1 2 10
1140 2 1 3/4 1 3
825 1.5 3/4 1/2 3/4

Motor Characteristics

Electrical Types Starting Torque Starting Current Efficiency Advantages Disadvantages Typical Applications
Three Phase High Medium Highest Highest Efficiency Fewest mechanical components Availability of three phase electrical power General or definite purpose use
Capacitor Start High Medium Medium Highly versatile for single phase use Slightly more expensive that split phase General or definite purpose use
Capacitor Start
Capacitor Run
High Medium High High efficiency Most costly combination General or definite purpose use (typically above 1.5 HP )
Split Phase Medium High Medium Slightly less expensive that capacitor start Higher starting current with less starting torque Belted fans and blowers Loads like tools where the load is applied after the motor is up to speed (typically under 3/4 HP)
Split Phase Start
Capacitor Run
Medium High High High efficiency Additional cost of the run capacitor Higher efficiency belt drive fans and blowers
Permanent Split Capacitor (PSC) Low Low High High efficiency No starting switch Starting torque too low for many applications Direct drive fans and blowers
Medium Medium Medium Easier instant reversibility No starting switch Not as much starting torque as capacitor start Large run capacitor required Door and gate openers Small gearmotors
Shaded Pole Lowest Low Lowest Least expensive No run capacitor required Lowest Efficiency Direct drive vans or blowers only Small direct drive fans and blowers (typically under 1/4 HP)