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82 Cards in this Set

  • Front
  • Back
TRUE OR FALSE

Pilot-duty devices are not normally used to switch horsepower loads.
TRUE
TRUE OR FALSE

A motor starter would normally be classified as a primary control device.
TRUE
TRUE OR FALSE

AC and DC contact current ratings are the same for a given switch.
FALSE
TRUE OR FALSE

Mushroom head pushbutton operators are used for emergency stop push-buttons.
TRUE
TRUE OR FALSE

A pushbutton assembly can have multiple contact block.
TRUE
TRUE OR FALSE

Using maintained contacts in emergency stop pushbuttons prevents a motor control process
from restarting until the maintained pushbutton is physically reset.
TRUE
TRUE OR FALSE

Emergency stop pushbuttons must be of the maintained contact type
TRUE
TRUE OR FALSE

The NEMA and IEC symbols for a pilot light are exactly the same.
FALSE
TRUE OR FALSE

Push-to-test pilot lights can be energized from two separate signals of the same voltage.
TRUE
TRUE OR FALSE

Drum switches are used for starting and reversing single phase motors that are designed for
reversing service
TRUE
Limit switches are usually actuated by hand.
FALSE
A micro switch is normally actuated by a permanent magnet.
FALSE
A flow switch is used to sense the height of a liquid.
FALSE
All selector switches operate with spring to provide momentary contact operation.
FALSE
An N.C. (normally closed) pushbutton makes a circuit when it is pressed and returns to its
open position when the button is released.
FALSE
A micro switch is capable of operating with extremely small pressure on its operating lever.
TRUE
Temperature switches open or close when a designated temperature is reached.
TRUE
All pressure switches use only N.O. (normally open) contacts.
FALSE
Sensors are devices that are used to detect and often to measure the presence of something.
TRUE
A proximity sensor can not detect the presence of an object without physical contact.
FALSE
An inductive proximity sensor can be actuated by non-conductive materials.
FALSE
The standard detectable target for an inductive sensor is made of a ferrous material.
TRUE
The proximity switch leakage current is due to the switching characteristics of solid-state
devices.
TRUE
Never directly operate a motor with a proximity sensor.
TRUE
Hysteresis is a desirable feature of a proximity sensor may prevent it from chattering.
TRUE
When the target enters the field of an capacitive proximity sensor the oscillator circuit stops
oscillating.
FALSE
Photovoltaic (solar) cells produce DC voltages.
TRUE
Light shinning on a photo conductive (photo-resistive) cell will cause its resistance to
increase.
FALSE
Color detection and discrimination are not possible with photoelectric sensors.
FALSE
The photoelectric sensor receiver is tuned to the emitter's modulation frequency, and will
only detect light pulses at the specific frequency.
TRUE
The size of a target for a photoelectric sensor may be as small as a needle.
TRUE
In a through-beam scan sensor the emitter and receiver are housed in the same enclosure.
FALSE
An ultrasonic sensor requires a constant current bias current between two of its terminals.
FALSE
As the temperature of a thermistor with a negative temperature coefficient increases, its
resistance increases.
FALSE
The basic operating principle of thermocouples is that the electrical resistance of metals
varies with temperature.
FALSE
The operating temperature range of the IC temperature sensor is much lower than that of a
thermocouple.
TRUE
A magnetic pickup sensor generates a voltage that is proportional to the speed at which it is
driven.
FALSE
An encoder sensor is used to convert linear or rotary motion into an analog signal.
FALSE
Encoder sensors are used in applications such as robotic control where positions have to be
accurately determined.
TRUE
The usual approach taken to measure fluid flow is to convert the kinetic energy that the fluid
has into some other measurable form.
TRUE
The contacts of an electromechanical relay are switched by energizing the contacts.
FALSE
The normally open contact of a relay is closed any time the coil is energized.
TRUE
For DC solenoids, a non-laminated frame and plunger is acceptable.
TRUE
An AC solenoid rated for 120-V direct current if connected to a 120-V alternating current
source would draw lower than normal current.
TRUE
Continuous duty is the same as 100% duty cycle
TRUE
If an AC solenoid sticks in the open position a burnout of the coil is likely.
TRUE
For most effective and efficient operation, the length of a solenoid stroke is kept as long as
possible.
FALSE
A brush-less DC motor, like the brush type, can be driven by connecting it to a source of
direct current.
FALSE
Generally, stepper motors are rated for less than 1 horsepower and are used in low-power
position control applications.
TRUE
All open loop control systems operate without feedback.
TRUE
All servo motors operate using a closed loop control system.
TRUE
Which of the following would be classified as a pilot control device?
PRESSURE SWITCH
The _______ push-button makes a circuit when it is pressed and returns to the open position
when the button is released.
N.O.
NEMA “types” enclosures are selected according to the
operating environment
Which of the following would be classified as a mechanically operated switch?
limit switch
When a metal object enters the high-frequency field of an inductive proximity sensor, it
causes
a decrease of energy in the oscillator circuit
Which of the following scan techniques is best suited for long-range scanning?
Through-Beam
Which of the following scan sensors is best suited to detect shinny targets?
Polarized Retro-reflective
Fiber optic sensor systems
are immune to electrical interference
Which of the following sensors is designed to sense the strength of a magnetic field?
Hall-effect sensor
Which of the following converts rotational speed into an analog voltage signal?
Tachometer
Which of the flow-meters operates by measuring the changes of induced voltage of a
conductive fluid?
Magnetic
The coil current for AC solenoids is primarily limited by the ______ of the coil.
inductive reactance
Which of the following would not be classified as an actuator?
Tachometer
Apprentice A says that the amount of puling or pushing force produced by a solenoid is
determined by the number of turns on the coil. Apprentice B says that is determined by the
amount of current flowing through the coil. Who is correct?
Both Apprentice A and Apprentice B
Solenoid valves are available to control ________ flow
ALL FLUIDS HYDRAULIC, PNEUMATIC AND WATER
A __________ solenoid valve blocks flow when the solenoid is De-energized and allows flow
when the solenoid is energized.
normally closed
For a DC stepper motor the amount of rotation is directly proportional to the:
number of pulses
_______ switches are small assemblies designed for mounting on printed circuit boards.
Micro
The break-make push-button is used for ______________ of control circuits.
jog, start and stop
The _______________ is the part of the push-button assembly that is pressed, pulled, or
rotated by the person operating the circuit.
e-stop
Selector switches require the operator device to be ____________ instead of pushed or
pulled to to actuate the attached contact block.
turned
A float switch is used to sense the_______ of a liquid.
amount
Drum switches are used for starting and _____________ motors.
reversing / direction
The main difference between inductive and capacitive sensors is that capacitive sensors
produce an ______________ field instead of an electromagnetic field.
electrostatic field
The two basic parts of a photoelectric sensor are the ________ and __________.
transmitter and reciever
The _________ technique refers to the method used by photoelectric sensors to detect a
target.
scan
__________ readers are used for sorting of products on a conveyor.
Bar code
Hall-effect sensors are used to detect the _____________ and ______________ of a
magnetic field.
proximity and strength
An ______________ sensor operates by sending high frequency sound waves toward a
target and measuring the time it takes for the pulses to bounce back.
ultrasonic
An actuator is any device that converts an electrical signal into ____________
______________.
mechanical movement
The stepper motor converts electrical pulses into discrete rotor movements called
____________.
steps or resolution