Motors 1
List the three basic types of DC motors.
Series, shunt, and compound.
_______ are the items that ride against the commutator to make electrical connections.
Brushes.
When the series and shunt windings are connected to aid each other in the production of magnetism, the connection is known as the __________ compound.
Cumulative
What is the formula for calculating efficiency?
ServoDiscs are also known as ________.
printed circuit motors.
The servomotor which has a fiberglass and copper rotor is the _______ motor.
ServoDisc
The motor that does not contain a wound armature, commutator, or brushes is the __________ motor.
brushless DC
When the series and shunt windings are connected to oppose each other in the production of magnetism, the connection is known as the __________ compound.
Differential.
What is the formula for calculating horsepower?
(1.59 x RPM x IN-LB) / 100,000
The position where the windings are parallel to the lines of flux and there is no induced voltage is called the __________.
neutral plane
The magnetic field can be provided by electromagnets that are wound around _______.
pole pieces
Small permanent magnet motors that have lightweight rotors are often used as _________.
servomotors
The setting of the amount of ______ in the series and shunt field windings determine the compounding.
currents
Calculate the horsepower for a motor that requires 143 in-lbs of torque and has a speed of 1250 RPM.
hp = 2.84
_________ motors are a brushless type that is shaped like a hollow cylinder or cup.
Inside-out motors
What are the two factors that determine the amount of torque produced by a DC motor?
The strength of the magnetic field of the pole pieces, and the strength of the magnetic field of the armature.
In a compound DC motor control circuit, the field loss relay will disconnect the _________ if power is lost to the _______.
armature, shunt field
What is another name for the series field shunt rheostat?
series field diverter
Calculate the efficiency for a motor with 120 V and a current draw of 2.6 A, that requires 12 in-lbs of torque and has a speed of 1300 RPM.
EFF = 59.37%
What kind of motors contain a wound armature and brushes like a conventional DC motor?
permanent magnet motors
List two ways to reduce current to the armature of a DC motor.
1) Connect resistance in series with the armature.
2) Use an electronic controller to supply variable voltage to the armature circuit separately from the load.
The amount of CEMF produced in the armature of a DC motor is proportional to...
The number of turns in the armature, the strength of the magnetic field of the pole pieces, and the speed of the armature.
Explain the differences between wave wound, lap wound, and frogleg.
Wave wound provides high voltage and low current, lap wound provides low voltage and high current, and frogleg provides moderate voltage and current.
Calculate the efficiency for a motor with 120 V and a current draw of 90 A, that requires 652 in-lbs of torque and has a speed of 1300 RPM.
EFF = 93.09%
Name two ways to reduce current to the DC motor armature.
1) Connect resistance in series with the armature.
2) Use an electric controller to supply variable voltage to the armature circuit separately from the field.