Industrial Motor Application
_________ is/are often listed in order from the most likely to cause the symptom to the least likely to cause the symptom.
Faults
_________ windings in a DC motor include series windings and shunt windings.
Field
Common parameters associated with jogging include: Jog __________, Jog Accel, and Jog Decel.
Frequency
Two common types of variable speed AC drives are ___________ and vector drives.
General-Purpose
When using a megger to test insulation, one probe is connected to the winding and the other probe is connected to __________.
Ground
___________ is deep groves cut into the brush sliding face.
Hair lining
The DC voltage should only be inserted for a short period of time to prevent excessive ________ of the motor windings.
Heating
When all the external resistance is removed, the current in the rotor windings is limited by the amount of _____________ in the windings.
Inductive Reactance
Each winding should have about 2 to 8 ohms of resistance end to end, sometimes slightly higher. Resistance should be _________ to the frame and to the other windings.
Infinite
Field windings should have about 1 to 10 ohms of resistance end to end, sometimes slightly higher. Resistance should be ________ to the frame and to other windings.
Infinite
Stopping a motor by creating a stationary magnetic field in the stator is called DC __________ braking.
Injection
____________ are commonly used to test the winding resistance to indicate if a winding is open, shorted, or good.
Multimeter
Megger test voltage is based on the field voltage rating found on the motor ___________.
Nameplate
The first step to diagnose a DC motor failure is to _____________ using four of the five senses.
Observe
The first step to diagnose an AC motor failure is to ________ using the four of the five senses.
Observe
An electromagnetic fail-safe brake is engaged when the power is ______.
Off
A result of the reduced phase angle is that more useful ________ is supplied to the motor.
Power
Failure to lock out the ________ can result in possible injury, death, or test equipment damage.
Power
Speed control for a wound-rotor motor is only possible within the _________ of the external resistance.
Range
With ___________ braking, electricity is actually put back into the system
Regenerative
The _______ column lists the steps to take to correct the fault.
Remedy
If a capacitor is shorted, the ohmmeter will constantly display ____ ohms.
0
The insulation resistance to ground should be _____ megaohm per kilovolt, with a 1 megaohm minimum for any megger test.
1
The insulation resistance to ground should be _______ megohm(s) per kilovolt, with a 1 megohm minimum for any megger test.
1
A DC voltage that is at least _____% of the motor's peak voltage is required to stop the motor's rotation.
3
Determine the more suitable motor for the following scenario. A fan in a ventilation shaft is difficult to reach. It needs to be quiet and have a long life with minimal maintenance.
AC Motor
Determine the more suitable motor for the following scenario. A rotary saw blade requires a variable torque load from 9800 rpm down to 1750 rpm.
AC Motor
Determine the more suitable motor for the following scenario. An industrial blower requires a motor that uses little power at startup and is highly efficient.
AC Motor
The ___________ of an electromagnetic brake is connected to the motor shaft and can rotate freely when the brake is released.
Armature
Fifty-one percent of AC motor failures are the result of _________ damage.
Bearing
Applications where motors need to be halted require the use if motor _________ techniques.
Braking
The commutator film color should be a uniform light to dark _______.
Brown
The first step to test a(n) _________ is to inspect for a bulged case of leaks.
Capacitor
Troubleshooting ________ aid the troubleshooting process by providing a logical path to follow.
Charts
A phase winding to frame short usually trips __________ or opens fuses.
Circuit Breakers
The ____________ section of a general-purpose drive uses rectifiers to convert AC to DC.
Converter
Two common applications of wound-rotor motors are large hoists and _______ that are in fixed positions.
Cranes
The next step is to measure __________, voltage, and speed with the motor running.
Current
Determine the more suitable motor for the following scenario. A process control system needs a tank agitator that can run using battery power in the event of an emergency.
DC Motor
The pressure plate works with the clapper to prevent motor rotation when the brake is in the ____________ condition.
De-energized
DC motors failures can be mechanical or __________ in nature.
Electrical
Plugging should only be used in __________ and/or non-repetitive situations where rapid stopping is not often required.
Emergency
In many applications, ___________ controls are required to control a variable speed drive.
External
A wound-rotor motor can provide __________ starting torque per amp of current than a standard induction motor
Higher
DC motors are usually heavier and larger than 3-phase motors of equivalent ____________.
Horsepower
As the external resistance is reduced, the current in the motor windings _____________.
Increases
Electromagnetic brakes are load ____________.
Independent
The __________ parameter establishes the deceleration rate for a motor when a jog input is released.
Jog Decel
If the time delay of the off-delay timer is too ________, the motor will stop but then accelerate in the reverse direction.
Long
AC motor windings typically only have a few ohms of resistance, so set the meter to the _________ resistance range.
Lowest
DC motor windings typically only have a few ohms of resistance, so set the meter to the _________ resistance range.
Lowest
A(n) ________ or plugging switch can be used to plug a motor.
Magnetic-Not right
AC motors failures can be _________ or electrical in nature.
Mechanical
A(n) _________ is an instrument that uses high voltage to test wire insulation.
Megohmmeter
A(n) _____________ is an instrument that uses high voltage to test wire insulation.
Megohmmeter
The most common electrical instrument used to test a DC motor is a(n) _____________.
Multimeter
Some drives include ____________ that can be used to turn on external devices such as indicator light.
Output Relays
Variable frequency drives provide inputs for line power and ___________ for the motor.
Outputs
Dynamic braking is used on cranes, elevators, and locomotives when a condition called _________ can occur.
Overhauling
A(n) ___________ motor has to work harder than it was designed to work, which can lead to premature failure.
Overloaded
Connecting the full resistance of the rotor windings decrease the ____________ between the induced voltage and the rotor current.
Phase Angle
A three-phase AC induction motor can be reversed by swapping two of its ___________.
Phases
Common inputs to a variable frequency drive include manual inputs, __________ devices, potentiometers, and PLCs.
Pilot
A method of stopping a motor by momentarily reversing its direction is __________.
Plugging
Using a drum switch, speed switch, and off-delay timers are all different methods of ________ a motor.
Plugging
The ________ leads on a wound-rotor motor are labeled M1, M3, and M3.
Rotor
A speed controller connects to the _________ of a wound-rotor motor and controls the speed of the motor by adjusting the resistance of the rotor circuit.
Rotor Windings
DC motor field windings are subject to ________ in a winding, an open winding, and individual windings shorted to the motor frame or to other windings.
Shorts
A typical three-phase wound-rotor motor has ______ leads.
Six
A wound-rotor induction motor, also called a(n) __________motor, is an AC motor that provides AC variable speed control by varying the resistance of its rotors.
Slip-Ring
The user of a variable frequency drive can select what signal will provide the _________ command.
Speed
When jogging with a variable frequency drive, the direction and __________ of jogging can be controlled.
Speed
A speed switch is connected to the motor either directly to the ________ or via mechanical linkage.
Speed Switch
Reversing any two ________ leads will reverse the rotation of a wound-rotor motor.
Stator
A typical troubleshooting aid is organized by the _________ they are meant to test.
Symptoms
A typical troubleshooting aid is organized by the __________ they are meant to test.
Symptoms
Industry standard is to reverse the T1 and _____ leads.
T3
The _______ Method column tells the technician what tests to perform.
Test
The _________ column tells the technician what tests to perform.
Test Method
An automatic speed controller uses __________ and control relays to change the resistance.
Timers
Most motors are megger tested at _________ the nameplate rating.
Twice
A(n) ________ drive includes a feedback device to provide speed and direction feedback.
Vector
Reversing the rotor winding leads _______ reverse the rotation of a wound-rotor motor.
Will Not
Motor overloading causes high _______ current and high temperature which causes the winding insulation to fail.
Winding
The method for reversing the rotation of a(n) _____________ is the same as for reversing the rotation of a standard three-phase induction motor.
Wound-Rotor Motor
Determine the more suitable motor for the following scenario. A transformer coil winder needs a motor that provides constant torque between 500 and 1300 rpm and is capable of running 125% overload throughout the speed range.
DC Motor
The rotor windings of a wound-rotor motor are connected in either wye or ______ configuration on one end.
Delta
Plugging a motor using a timer is ____________ on the load.
Dependent
Depending on the drive, the inputs used to jog the motor may be _________ than the inputs used for standard control.
Different
One method of plugging a motor is to use a(n) _________ switch.
Drum
The rotation speed of a wound-rotor motor depends on the amount of ___________ connected to the rotor windings.
External Resistance
An example of a manual controller is a drum-type controller or a(n) ___________ controller.
Faceplate
________ is/are often listed in order from the most likely to cause the symptom to the least likely to cause the symptom.
Faults
The winding of a three-phase AC motor is tested by measuring the ________ with a multimeter.
Resistance
The external rotor circuit of a wound-rotor motor often consists of three high-wattage variable ________.
Resistors
To stop a motor, a(n) _________ on the brake pulls the clapper against the armature.
Spring
________ windings draw heavy current at startup. They are switched out of the power circuit by the centrifugal switch.
Start
One of the disadvantages of using an AC drive and motor instead of a DC drive and motor is that the AC motor cannot match the DC motor's __________ torque.
Starting