Unite 17 Types Of Electrical Motor Flashcards
Motors have two different current ratings, the full-load or rated amps (FLA or RLA) and the ____________.
locked-rotor amps
The difference between the motor’s calculated and actual speed is called _______.
motor slip
The _________ is used with some motors to open the start windings after the motor has started.
Start capacitor
The amount by which the current leads or lags the voltage is called phase angle.
True or false
True
A start capacitor is wired into the circuit to provide the most efficient phase angle between the current and voltage when the motor is running.
true or false
False
When enough back EMF has built up, called _______ voltage, the contacts between terminals 1 and 2 of a potential relay will open.
Pick up
A positive temperature coefficient resistor (PTCR) increases ______
its resistance as its temperature increase
The resistance between the terminals of a three-phase compressor motor __________.
Is the same
The two basic types of converters are the phase-controlled rectifier and the diode bridge rectifier.
True or false
True
A _________ receives a fixed DC voltage from the converter and then pulses the voltage to the motor.
Pulse with modulators
When an alternating current is applied to
the running windings of a split-phase electric motor, an
alternating current. __________________________
with reverse polarity is induced in the rotor
A two-pole split-phase motor operates at a speed
just under
3600 rpm
The start windings has
more turns than the run winding
A four-pole split-phase motor runs __________
Slower than
When a typical split-phase motor reaches approximately 75% of its operating speed, the start winding circuit is removed from the circuit by a
Centrifugal switch
A three phase power supply can be found in most
Factories
The electronic relay is used with some electric
motors to open
the circuit to the start windings after
motor has started
The amount by which the current leads or lags
the voltage in alternating current circuit is known as the
Phase angle
In an alternating current circuit in which there is
the voltage capacitor, the current __________ the voltage
Leads
Capacitors wired in series with the start windings
provide
A greater starting torque
The shaded-pole motor has
little starting torque
Three-phase motors have
no start windings or start capacitors.
The tem “slip” is used to indicate
the difference between the full operational
rpm rating of the motor and the actual speed
under a load
The hermetic motor must run in a
refrigerant vapor atmospheres
The start winding circuit in a hermetic motor is
interrupted by a potential relay or a current relay
because______________ mechanical switch
of the electric are produced by a mechanical switch
The positive-temperature-coefficient start device is
a type of
Thermistor
A two-speed compressor motor may operate as a
two- or four-pole motor
Most small hermetic motors are cooled by
refrigerant gas
(PTCR) means
Positive temperature coefficient resistor
What device may be wired into the running circuit of a motor to improve the running efficiency?
Run capacitors
The two types or relays used to start hermetic compressors are
Potential relays, and current relays.
Question
An
