DC
Speed regulation of a DC motor is proportional to the :
Resistance of the armature
3 types of motors
Series
Shunt
Compund
Rarely used compound motor
Differential
Brush-less DC motors that require very smooth operation such as grinders that produce a finished service are powered by
sine waves
Find speed:
80 poles
50 HZ
75
when reduced voltage is applied to the armature and full voltage is maintained to the shunt field, the motor operates at
underspeed
"constant speed motor" is also referred to as
shunt motor
Torque is a force that tends to cause
Rotation
how is a motor operated at under speed?
when reduced voltage is applied to the armature and full voltage is maintained to the shunt field
Percent slip:
S=1800
RPM=1725
4.16
most converters that supply power to brushless DC motors produce a:
Trapezoidal Wave
Cumulative compound motor connection means that the fields of the series and shunt field winding
Add
It is alright to operate a series motor with no load
True/False?
False
What is base speed?
when full voltage is applied to both the armature and the shunt field
480-VDC line has a current draw of 35A
625 in-Ib
2000 RPM
what is the HP
19.875
what motor can develop extremely high starting torque
Series Motor
In a compound DC motor control circuit, the field los relay will disconnect_ if power is lost to the_
Armature, shunt field
Some DC servomotors have square wave input voltage. to vary the motor speed, the on and off time ratio of the square wave is varied. this is called?
Pulse-Width modulation
Permanent magnet motors have _ efficiency then wound field motors
Higher
120 VDC line has current draw of 54A
400 in-IB
1250 RPM
what is the efficiency
91.52%
Small permanent magnet motors that have lightweight rotors are often used as
servomotors
A force that tends to cause rotation
Torque
Another name for a printed Circuit motor
Servodisc
When a DC machine is used as a motor what function does the commutator perform?
performs the function of a rotary switch and maintains the correct direction of current flow through armature windings.
120 VDC line has current draw of 90A
652 in-lb
1300 RPM
what is the efficiency
93.09%