Document jm9240qD81y8JLYoZ0vXpBY4p
620
CHAPTER 35
1946 Guide
Typical Specifications for Single Phase Motors .
..........................Hp,.......................... RPM,
Cycles,
Volts, Single Phase Motor of
the...................................................Type for Driving.........................................1....... Motor Shall
(Capacitor, Split Phase, etc.)
(Application)
Be Arranged/or jvertical^} Mounting And Shall Be Provided With
a...................................... ..... ............... Type of Enclosure, NEMA
(Open, Splashproof, etc.)
^
{sleeve} Bear*n&s:
Insulation, And
Typical Specifications for Squirrel-Cage Motor Control
Control for Squirrel-Cage.................... ..................... Motors Shall Consist of An Enclosed (Fan, Pump, etc.)
{Maggie} Type{R^JhVoITta|e} Starter Providin* verload Protection And
Low Voltage
Control Shall Include A Safety Disconnect Switch
(fn^ CommonEndosure} With the Starting Control.e, /
Typical Specifications for Wound Rotor Motor Control Control for Wound Rotor Motor Control for........ Applications Shall Consist of a Safety
(Fan, Pump, etc.) Disconnect Switch, a {olminon^} Mounted Across the Line Starter Providing Over-
load Protection, Low Voltage {r^ST"}' and a SeCOndary {l^S" Regulating}
Controller for (M^ndng^in slmfEnclosure}' Primary and Secondary Contro1 Sha"
Be Interlocked so as to Provide Complete Control from the Rheostat Handle.
the commutator when the. motor comes up to speed. These, motors are
suitable for applications such as industrial compressors where high
break-away torque is required and where commutator and brush noise
are not factors.
-
Split Phase motors have a high resistance auxiliary winding which is in the circuit during starting but is disconnected through the action of a
centrifugal switch as the motor comes up to speed. Under running con ditions it operates as a single phase induction motor with one winding in the circuit. These units are available for the squall"horsepower ratings and when equipped-with-a high slip rotor may be used for adjustable
PER CENT OF FULL LOAD TORQUE
FrG. 9. Performance Characteristics of A Wound Rotor Motor wtth External Resistance
varying speeds through line voltage control. The motors are ideally suited for fan duty.
Speed-torque characteristics of single phase motors are shown in Fig. 10. Typical specifications for single phase motors are shown on page 620.
CONTROL FOR ALTERNATING CURRENT MOTORS Squirrel-Cage motors are usually linestarted where power company limitations permit. In sizes up to 2 hp the motors are started by means of manual switches with an overload current element for motor protection.
Fig. 10. Speed-Torque Characteristics of Single Phase Motors..