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WorksheetsIDA 201 Final
Total questions: 66
Worksheet time: 33mins
When a Capacitor Start Induction Run (CSIR) motor is running and up to speed, what is the total capacitance acting on the motor? (Assume the run capacitor is 5 microfarads and the start capacitor is 20 microfarads, if present.)
4 microfarads
5 microfarads
20 microfarads
25 microfarads
A motor's speed is determined by ____.
size
voltage
amperage
number of motor poles
Where would a water regulating valve that is controlling head pressure be installed?
Water circuit at inlet of condenser.
Discharge line at outlet of compressor.
Suction line.
Liquid line close to the condenser.
Grounding straps are required on resilient mounted motors to ____.
prevent rotation of the motor in the mount
help reduce motor vibration transfer to the object on which the motor is mounted
ground the motor in case of winding failure
act as the position for locating the motor leads
A slotted screw at the bottom of the bearing housing is called a ____.
drain plug
purge screw
relief plug
retaining screw
The heat anticipator in the thermostat control circuit in the heating mode is active when the ____.
heating contact is open
heating contact is closed
fan switch is open
fan switch is closed
The positive temperature coefficient resistor start device is a type of ____.
capacitor
variable resistor
switching device
diode
Which of the following voltages are not safe for a 208-V motor to operate?
170 volts
220 volts
238 volts
Both 170 volts & 238 volts
Capacitors wired in series with the starting winding provide a(n) ____.
longer starting time
greater starting torque
aid in starting three phase motors
more efficient operation at full load speed
If the resistance of the run winding decreases, the ____.
motor probably will not start
motor will draw too much current while it is running
centrifugal starting switch will not start the motor
load on the motor is probably too great
A permanent split capacitor (PSC) motor that is running and up to speed will have the start winding ____.
energized
de-energized
in series with the run winding
removed from the circuit
When a Capacitor Start, Capacitor Run (CSCR) motor initially starts, what is the total capacitance acting on the motor? (Assume the run capacitor is 5 microfarads and the start capacitor is 20 microfarads, if present.)
4 microfarads
5 microfarads
20 microfarads
25 microfarads
The recommended way to discharge a capacitor is to ____.
place a screwdriver across the terminals
assume it will discharge itself over a period of time
use a 20,000 ohm 5 watt resistor that has had insulated leads soldered to it
use an ohmmeter
A solder pot is part of a ____.
one-time fuse
resettable circuit breaker
time-delay fuse
plumber's tool kit
A sleeve bearing would typically be used in a motor that operates with a ____.
light load and where noise is a factor
heavy load and where noise is a factor
heavy load in a dirty atmosphere
heavy load in a moist atmosphere
When a contactor's coil is energized, how much resistance should be measured between terminal "L1" and terminal "T1"?
zero ohms
50-3000 ohms
5000-6000 ohms
infinite
Standards for motor overload protection are set by the ____.
United States Department of Transportation
National Electrical Code
Environmental Protection Agency
American National Standards Institute
A megger ____.
is an ammeter that can measure very small amounts of current
is a digital voltmeter that measures very high resistances
measures high voltage direct current
measures very high resistances
The motor that should be used in a potentially wet area is a(n) ____ motor.
enclosed
drip proof
explosion proof
open
Technician "A" says that a shorted winding will result in an increased current flow through the winding. Technician "B" says that if a motor is to be replaced, a motor with a lower horsepower rating should always be used. Which of the following statements is correct?
Technician "A" is correct. Technician "B" is correct.
Technician "A" is correct. Technician "B" is incorrect.
Technician "A" is incorrect. Technician "B" is correct.
Technician "A" is incorrect. Technician "B" is incorrect.
If the voltage supplied to the motor is well below the motor rated voltage, the current draw will be ____ it should
be.
lower than
the same as
higher than
in reverse polarity than
Beside maintaining pressure on the contacts for current carrying capacity, the pressure springs have a second important function. This is to ____.
keep the contacts in line
help obtain equal contacts against the stationary contacts
slow down the pull of the armature into place to reduce the noise
increase the power required to close the contacts
The shaded pole motor ____.
has little starting torque
has excessive starting torque
has greater efficiency than most split-phase motors
will start against a heavy starting load
What is meant by the term "detent"?
Slow motion of a contact to ensure good electrical contact.
Rapid making and breaking of a contact.
The compensation furnished by heaters in the thermostat.
The control of the blower in the air handler.
Which of the following overload devices is not affected by ambient temperature?
solder pot
magnetic
bimetal
time-delay fuse
A low pressure control has a "high event" and a "differential" setting. The technician wants the system to turn on at 28 psig and shut down at 2 psig. What would be the proper settings?
High event: 28 psig, differential: 2 psig.
High event: 2 psig, differential: 2 psig.
High event: 28 psig, differential: 26 psig.
High event: 2 psig, differential: 28 psig.
Why are explosion-proof motors not normally used on standard equipment?
They are too large.
They are too noisy.
They are too expensive.
They cannot be replaced.
Technician “A” says that if you take a voltage reading from terminal "L1" to terminal "T1" on a contactor whose coil is energized, you should read zero volts. Technician “B” says that contactors can only have normally open contacts. Which of the following statements is correct?
Technician "A" is correct. Technician "B" is correct.
Technician "A" is correct. Technician "B" is incorrect.
Technician "A" is incorrect. Technician "B" is correct.
Technician "A" is incorrect. Technician "B" is incorrect.
To prove that the combustion blower motor is operating before ignition, a ____ would be used.
toggle switch
pressure differential switch
push button switch
sail switch
A direct-drive motor is usually connected to a load with a ____.
cradle mount
rigid base mount
pulley
coupling
A split-phase has a ____ winding and a ____ winding.
start, run
start, common
common, run
run, common
Three phase motors have ____.
three start and three run windings for each phase
one start and one run winding for each phase
run windings only
a start switch in each phase circuit
If an air conditioning system is calling for cooling and the compressor is running but the indoor (evaporator) fan is not running, which terminal on the thermostat will the technician most likely check first?
G
R
Y
W
A split-phase motor that has a current relay and a start capacitor is called a(n) ____ motor.
Capacitor Start, Capacitor Run (CSCR)
Capacitor Start, Induction Run (CSIR)
Induction Start, Induction Run (ISIR)
Permanent Split Capacitor (PSC)
The purpose of a heat anticipator is to ____.
anticipate a sudden rise in temperature
keep the thermostat warm
reduce the temperature swing of a conditioned space
ensure that the system transformer does not overheat
When a water regulating valve is used to control the head pressure of a water-cooled system, the valve's spring is acting against which pressure to modulate the water flow?
Head pressure of the system.
Water pressure.
Atmospheric pressure.
Suction pressure.
To control ice build-up on a heat pump outdoor coil in the heating cycle, a ____ is attached to a large diaphragm.
toggle switch
micro-switch
push button switch
sail switch
The alignment of a motor and the driven mechanism must be done at room temperature and ____.
after heating with a torch
at operating temperature
after running for one minute
again after several days of operation
A permanent split-capacitor motor has a ____.
start and run capacitor
start capacitor only
run capacitor only
split phase capacitor
The width of a drive belt is classified as ____.
large or small
narrow or wide
large or small
narrow or wide
1 OR 2
The starting device usually used on single phase, fractional horsepower motors requiring low starting torque is the____.
potential relay
current relay
centrifugal switch
differential relay
An inherent motor protector is a ____.
circuit breaker
motor starter overload
thermally activated device in the motor winding
line fuse
A common practice in condensing units is to use a contactor with only one set of contacts opening only one side of the power to the unit. This is to ____.
reduce the cost of the contactor
make it easier to wire the unit
teach the service technician not to put hands in the unit with the power on
provide off-cycle heat to the compressor
A technician needs to check a single-phase compressor. He labels the three terminals "A," "B," and "C" and takes resistance readings of the windings. He reads 10 ohms from "A" to "B," infinity from "B" to "C," and infinity from "C" to "A." Identify the terminals.
A: common B: start C: run
Cannot identify terminals: winding grounded
A: start B: run C: common
Cannot identify terminals: open winding
The locked-rotor amperage is normally ____ times as great as the run-load amperage.
2
3
5
10
If a motor hums but does not start, there is a potential problem ____.
with the starting components
with an open winding
with insufficient supply voltage
all of the above
Most electrical problems with an electric motor are ____.
short circuited windings, closed windings, and grounded windings
short circuited windings. open windings, and grounded windings
all of the above
none of the above
Start windings are placed ____ with the run windings.
180 degrees out of phase
in phase
slightly out of phase
in series
The voltage tolerance of a standard electric motor is ____.
+5% -10%
+10% -5%
+10% -10%
+15% -15%
The cold anticipator is wired in ____ with the mercury bulb cooling contacts and is energized during the off cycle.
parallel
series
sequence
opposition
Technician "A" says that while checking the windings of a compressor, a reading of 10 ohms or less from the common terminal to ground indicates that the motor is okay. Technician "B" says that the resistance of the start winding should always be less than the resistance of the run winding. Which of the following statements is correct?
Technician "A" is correct. Technician "B" is correct.
Technician "A" is correct. Technician "B" is incorrect.
Technician "A" is incorrect. Technician "B" is correct.
Technician "A" is incorrect. Technician "B" is incorrect.
The service factor of an electric motor is determined by ____.
National Electrical Code
National Electrical Manufacturers Association code
motor's reserve capacity
the required wire size supplying power to the motor
When referring to motors, to what does the "insulation class" relate?
the noise level of the motor
the type of base on which the motor is mounted
the normal operating temperature of the motor
the noise level of the motor & the type of base on which the motor is mounted
A current magnetic relay opens and closes its contacts based on the ____.
current in the start winding
voltage across the start winding
voltage across the run winding
current in the run winding
If a condenser fan motor grounds out, it will usually ____.
trip a circuit breaker to shut off the unit
keep running as the current is only going to ground
run a little faster because the amperage draw will increase
cause the evaporator to ice up
If the suction pressure of a system is 60 psig and the oil pump outlet is 85 psig, what is the net oil pressure?
60 psig
25 psig
85 psig
145 psig
An example of a power consuming device would be a(n) ____ while an example of a non-power consuming device would be a(n) ____.
single-pole single-throw switch, light bulb
light bulb, electric motor
electric motor, light bulb
light bulb, single-pole single-throw switch
All control systems can subdivided into ___, no matter how many controls there are.
throttle loops
control loops
control segments
sensor segments
in most system compressors, the compressors are controlled with a ____.
pressure switch
heat switch
limiter
governor
____ control systems were used before electronics.
Pneumatic
Manual
Digital
Mechanical
A ____ is either in the pressure reducer or in the downstream side of the system to ensure that the control air pressure does not exceed about 30 psig
Blowback Valve
Relief Valve
Pulldown Valve
Pressure Valve
Most system compressors provide ___psig of air to the storage tank
90 to 100
90 to 125
100 to 125
100 to 150
Controlling the water flow to the room's needs is called ____.
Modulating flow
Regulating flow
Operating flow
Systemic flow
A device called a ____ is used to control the large volume of air in a air conditioning system.
Pilot lockout
Pilot positioner
Pilot fixator
Pilot engagement
As loads are added in a parallel circuit, the total resistance of the circuit ____.
will increase
will remain the same
will decrease
cannot be determined
A ___ reacts to stop, start, or modulate the flow of water, air, or refrigerant to the system or conditioned space
sensor
controller
controlled device
none of the above
