83%
Standard motors have an average efficiency of _____%
torque
_____ is the force that produces rotation in a motor
3300
Usual service conditions for a motor include exposure to an altitude of not more than _____
NEME
Motor frames are classified by ____
premium
The difference in the purchase price of an energy-efficient motor and a standard motor is the price ____.
x 16
To find a large motor frame number, multiply the base -to-shaft center distance by ____.
0.75" O-Rod or 3/4
The openings of a guarded, open motor enclosure do not permit passage of an ___" diameter rod.
torque and good speed
DC motors provide high ___ in smaller sizes than AC motors.
15% to 30%
An energy-efficient motor typically costs ___% more than an equivalent standard motor.
shunt
A DC ___ motor is used where a constant or variable speed is required.
start windings
The direction of a rotation for 1 phase motors is reversed by reversing the current flow in the _____/
two capacitors
A capacitor start -and-run motor uses ____ capacitors.
three
____-phase motors are the most common motors used in industry.
1 %-4%
An induction motor runs from within 1% to ____ % of synchronous speed.
1HP
A universal motor is usually available in sizes of less than ____ HP.
10%
The voltage of a motor should be _+ ____% of rated voltage.
break down torque
____torque is the maximum torque a motor can provide without an abrupt reduction in motor speed.
100 degrees
A splashproof, open motor enclosure provides protection against liquid drops and solid particles within 0 degrees to ____ of vertical.
true
If a motor is operated often, an energy-efficient motor is more cost efficient.
true
AC voltages usually vary more than DC voltages
true
Open motor enclosures allow air to cool the motor windings
false
A synchronous motor has generally good starting torque
true
A universal motor can operate on AC or DC
true
electric motors change electrical energy into mechanical energy
false
Full-load torque is the torque required to bring a load up to the correct speed
true
The horsepower of a motor is a factor in determining how fast a load turns
true
An explosionproof, enclosed motor enclosure is not self-equipped for cooling enclosed parts
true
a series motor is used when high starting torque is required.
true
a shunt motor runs at almost the same speed at any load within its rating
true
the most cost-efficient motor type is a 3 phase motor
true
very damp or very dry locations are classified as unusual service conditions.
false
the starting torque of a shunt motor is about 250% to 350% of its full-load torque
true
motor frequency should be within +_ 5% of rated frequency at the rated voltage7
false
a permanent-magnet motor has a synchronous speed
83 or 89
Energy-efficient motors have an average efficiency of ___%
number of kWh used
The cost of electrical power is based on the ____
move in one direction
A rectifier is a component that converts AC to DC by allowing the current to be ___
746 W
A horsepower is a unit of power equal to
locked rotor
___torque is the torque a motor produces when the rotor is stationary and full power is applied
150
A class B motor increases the starting torque of the motor by ___%
40
Usual service conditions to satisfy a motor's environmental requirements include an ambient temperature of not more than ___ degrees C.
G
A motor frame with the letter ___ can be used with a gasoline pump motor
15
a dripproof, open motor enclosure protects motor windings against liquid drops and solid particles with 0 degrees to ___ of vertical
400
The starting torque of a DC series motor is ___% to 450% its full-load torque.
shaded-pool
A ____ motor is the most simple and least expensive 1 phase, AC motor
mechanical
___input are activated by a moving part, like limit switches
more to purchase and less to operate
An energy-efficient motor costs ___ than a standard motor.