Rotating device for cooling motors.
Directs air flow over motor and also protects fan.
Base which supports motor for mounting.
A term commonly used to describe the stationary (stator) member
of a DC motor. The field provides the
magnetic field with which the mechanically rotating (armature or rotor) member
interacts. The introduction of resistance in series with the shunt wound
field of DC motor to reduce the voltage and current which weakens the strength
of the magnetic field and thereby increases the motor speed. Mounting endshield with special rabbets and bolt holes for
mounting such equipment a pumps and gearboxes to the motor or for overhanging
the motor on the driven machine. The magnetic field which is established around an energized
conductor or permanent magnet. The field is represented by flux lines creating
a flux pattern between opposite poles. The
density of the flux lines is a measure of the strength of the magnetic field. A figure of merit which indicates how much rectified current
departs from pure (non-pulsating) DC. A
large departure from unity form factor (pure DC) increases the heating effect
of the motor and reduces brush life. Mathematically,
form factor is the ration of the root-mean square (rms) value of the current
to the average (av) current or Irms/lav. A type of coil in which each winding is individually formed
and placed into the stator slot. A cross
sectional view of the winding would be rectangular. Usually form winding is used on high voltage
(2300 volts and above) and large motors (449T and above). Form winding allows for better insulation on
high voltage than does random (mush) winding. FRACTIONAL-HORSEPOWER MOTOR (FHP) A motor usually built in a frame smaller than that having a
continuous rating of one horsepower, open construction, at 1700 – 1800 rpm.
Within NEMA frame sizes, FHP encompasses the 42, 48 and 56 frames.
(In some cases the motor rating does exceed one horsepower, but the frame
size categorizes the motor as a fractional.) The height in inches from the center of the shaft tot he bottom
of the base can be calculated by dividing the frame size by 16. The supporting structure for the stator parts of an AC motor.
In a DC motor, the frame usually forms a part of the magnetic coil.
The frame also determines mounting dimensions. Refers to a set of physical dimensions of motors as established
by NEMA. These dimensions include critical
mounting dimensions. NEMA 48 and 56
frame motors are considered fractional horsepower sizes even though they can
exceed one horsepower. NEMA 143T to
149T is considered integral horsepower AC motors and 5000 series and above are
called large motors. The rate at which alternating current makes a complete cycle
of reversals. It is expressed in cycles
per second. In the U.S., 60 cycles (Hz)
is the standard while in other countries 50 Hz (cycles) is common. The frequency of the AC current will affect
the speed of a motor. The front end of a normal motor is the end opposite the coupling
or driving pulley (NEMA). This is sometimes
called the opposite pulley end (O.P.E.) or commutator end (C.E.) The current flowing through the line when the motor is operating
at full-load torque and full-load speed with rated frequency and voltage applied
to the motor terminals. The torque of a motor necessary to produce its rated horsepower
at full-load speed, sometimes referred to as running torque.FAN SHROUD
FEET
FIELD WEAKENING
FLUX
FORM WOUND
FRAME
FREQUENCY
FULL-LOAD CURRENT