Motor controls 2
If a programmable timer is programmed for a time setting of 1020 and the time base is programmed for 1 second, how long is the timer programmed for?
1020 seconds
An increase in the ambient temperature will increase the amount of current required to trip overloads.
False
Copper contacts are better than silver alloy contacts because they are more arc resistant, provide good conductivity, and last longer.
False
Drum switches are considered motor starters because they have no overload protection.
False
Mechanical interlocks are auxiliary contacts that prevent a motor from being reversed by opening the control circuit to the other starting coil that is not already energized.
False
The dot in a joystick represents the position of the switch in which the contacts used in that part of the circuit are closed.
False
The moving part of the limit switch is drawn below the contacts in the symbol, if the switch is NC/NC held open.
False
overload relays are extremely quick to resetbecause they do not require a cooling-off period before being reset.
Magnetic
If a flow switch is used to sound an alarm when there is no flow, are NO or NC contacts used to control the alarm?
NC contacts
If a pressure switch is used to maintain a set pressure, are NO or NC contacts used to control the compressor motor starter?
NC contacts
If a voltage is measured going into a control switch and no voltage is measured going out of the switch, what operating conditions might the switch be in?
NC or NO held closed
If a fuse or circuit breaker directly opens a circuit when the circuit limit is reached, do overload heaters open and break the circuit when their current limit is reached?
No
In a 1f motor starter, does the starter have to open both the ungrounded (hot) conductor and the neutral conductor?
No
A selector switch is a switch with an operator that is _____ to activate the electrical contacts.
rotated
Reversing the rotation of 1 phase motors is accomplished by interchanging the leads of the starting or _______windings.
running
An advantage of _____ contacts is that the oxide (rust) that forms on the metal is an excellent conductor of electricity.
silver alloy
To reverse a running motor using a drum switch, the handle must first be movedto the center position until the motor ____ and then moved to the reverse position.
stops
A fork lever actuator is an actuator operated by one of _____ roller arms.
two
A selector switch with a legend plate labeled SLOW/FAST is an example of what type of selector switch?
two position selector switch
Always consult the manufacturer_____ to ensure prper wiring.
wiring diagram
Manual contactors are normally used ____
with lighting circuits
If a programmable timer is programmed for a time setting of 1020 and the time base is programmed for 0.1 seconds, how long is the timer programmed for?
102.0 seconds
Dashpot, synchronus clock, and solid-state timers are _____ timers.
. stand-alone
When troubleshooting a contactor or motor starter, the voltage is acceptable if the voltage reading is within _____% of the motor voltage rating.
10
If a motor has an 8 A FLC rating and a service factor of 1.25, how much current is the motor designed to handle for short periods of time?
10 A
When programming a real-time clock to operate its contacts from 4:30 PM to 6:00 PM, what is the time setting in military time?
1630-1800
A _____V, 1 f powers source has two hot wires, L1 and L2 (ungrounded conductors) and no neutral.
230
Is a diode used to help protect contacts in an AC load switching circuit or a DC load switching circuit?
DC load switching
loads are the least destructive loads to switch.
Resistive
____ timers are normally discarded when they fail since they cost less than other timers.
Solid-state
____ timers are the most common stand-alone timers used in control applications today.
Solid-state
Line diagrams may use a(n) _____ to indicate which joystick position will operate the contacts.
dot
switches are control devices that react to heat intensity.
Temperature
A motor controlled by a motor starter draws the highest amount of current when starting.
True
A retentive timer is a type of timer that retains its accumulated time value after a power loss.
True
A starting winding of a 1 phase motor has higher resistance.
True
Arc chutes are used to help confine and extinguish arcs faster.
True
DC circuits causes the most problems in arc suppression as opposed to an AC circuit.
True
Despite being eliminated for direct control of motors, knife switch operation is still used today but in the form of electrical disconnects.
True
In reversing motor starters, mechanical interlocks prevent both sets of control contacts from closing at the same time.
True
Manual contactors not used to control motors because they don't have overloads.
True
Mechanical interlocks are shown by a brocken (dashed) line between the forward coil and reverse coil symmbols in the line diagram.
True
Pushbutton interlocking prevents a motor from being reversed when the motor is already running in one direction and the pushbutton for the other direction is pressed by opening the control circuit to the energized starting coil before energizing the other starting coil.
True
The advantage of using a drum switch over a pushbutton and a magnetic motor starter is the drum switch only has one handle; therefore, the operator does not have to move a hand off the controller when controlling loads that require the operator to keep both eyes on moving load.
True
The moving part of the limit switch is drawn above the contacts in the symbol, if the switch is NC/NC held open.
True
Can one pushbutton operate both NO and NC contacts?
Yes
Can the power line fuses be checked in the power circuit, even if the control circuit is not working?
Yes
Do all ungrounded (hot) conductors have to be opened when controlling loads?
Yes
___ timers are the oldest type of industrial timers.
__Dashpot
A _____ is not a common sensing device used by most pressure switches.
barometer
A(n) _____ overload relay is an overload relay that resets automatically.
bimetallic
A _____ is an overcurrent protection device with a mechanism that automatically opens the circuit when an overload condition or short circuit occurs.
circuit breaker
The most common problem of contact-based timing circuits is _____ failure.
contact
A _____ is not a basic actuator used on limit switches.
contact pole
The ___ circuit includes the required circuit inputs(pushbottons, limit switches, etc), motor starter coils, motor starter coils, motor starter auxiliary contacts, overload contacts, timers, and counters.
control
A _____ is used to change the amount of current flowing to a motor but reduces the current to a lower value for the overload relay.
current transformer
A _____ timer is a timer that provides time delay by controlling how rapidly air or liquid is allowed to pass into or out of a container through an orifice (opening) that is either fixed or variable in diameter.
dashpot
Which type of timer can provide a time delay between activation and contact actuation, but its time time setting cannot be precisely set and it cannot be set for long periods of time?
dashpot
Although most magnetic reversing starters provide mechanical interlock protection, some circuits are provided with a secondary backup or safety backup system that uses auxiliary contacts to provide____ interlocking.
electrical
The direction of rotation may be reversed in a DC motor by reversing the direction of the current through the armature without changing the direction of the current through the_____.
fields
Most _____ switches use a paddle to detect the movement of a product.
flow
For fully reliable motor protection, heat coils should be selected based on the motor _____ rating shown on the motor nameplate.
full-load current
What position are most flow switches designed to operate in?
horizontal
A motor that is starting draws a tremendous _____ current (normally six to eight times the normal current) when the circuit is closed.
inrush
Drum switches are totally enclosed and a(n) ____ provides the means for moving the contacts from point to point.
insulated handle
A___ circuit allows the operator to start a motor for short times without memory.
jogging
A _____ is an operator that selects one to eight different circuit conditions when it is shifted from its center position.
joystick
A(n) _____ button operator can be operated from any angle and is used in applications that require fast operation such as emergency stops, motor stops, and valve shutoffs.
jumbo mushroom
What is the best type of pushbutton operator to use in an emergency stop application?
jumbo mushroom button operator
If several connections of a given number are required, ___ can be added to the terminal strip to provide multiple connection points to one given terminal number.
jumpers
A _____ switch is a mechanical input that requires physical contact of the object with the switch actuator.
limit
switches may be used to provide automatic control of reversing circuits.
limit
A _____ rotor is a condition when a motor is loaded so heavily that the motor shaft cannot turn.
locked
A_____ starter is a contactor with an added overload protective device.
manual
A(n) _____ is the arrangement of contacts in such a way that both sets of contacts cannot be closed at the same time.
mechanical interlock
AC manual starters are selected based on phasing, voltage, starter size, enclosure type, and _____.
number of poles
What type of timer is used to control the fan motor in a furnace so that the fan continues to operate for a time after the heating source is turned off in order to distribute the remaining heat from the furnace?
off-delay
A(n) _____ timer can be designed to open or close a circuit after a preset time delay.
on-delay
What type of timer is used to control the light in a garage door opener so that the light turns on when the opener is activated and remains on for a set period of time after the opener button is released?
on-delay
In a truth table, an O represents what condition of the contacts?
open
A pressure switch is rated according to its _____ pressure range.
operating
In a(n) _____ diagram, the top line shows the position of the control switch and the bottom line shows the condition of the load.
operational
Drum switches are not motor starters because they do not contain_____.
protective overloads
A _____ actuator is an actuator operated by direct forward movement into the limit switch.
push-roller
he T-frame used with a 3 f manual contactor is activated by a _____ mechanism.
pushbutton
