WorksheetsIDA-201 Unit 18
Total questions: 30
Worksheet time: 15mins
Name
Class
Date
1.
Which of the following voltages are not safe for a 208-V motor to operate?
a)
170 Volts and 238 Volts
b)
170 Volts
c)
238 Volts
d)
220 Volts
2.
If the voltage supplied to the motor is well below the motor rated voltage, the current draw will be ____ it should be.
a)
higher than
b)
lower than
c)
the same as
d)
in reverse polarity than
3.
The voltage tolerance of a standard electric motor is ____.
a)
+10% -10%
b)
+5% -10%
c)
+10% -5%
d)
+15% -15%
4.
The locked-rotor amperage is normally ____ times as great as the run-load amperage.
a)
5
b)
2
c)
3
d)
10
5.
The motor that should be used in a potentially wet area is a(n) ____ motor.
a)
drip proof
b)
enclosed
c)
explosion proof
d)
open
6.
When referring to motors, to what does the "insulation class" relate?
a)
the normal operating temperature of the motor
b)
the noise level of the motor
c)
the type of base on which the motor is mounted
d)
None of the above
7.
A sleeve bearing would typically be used in a motor that operates with a ____.
a)
light load and where noise is a factor
b)
heavy load and where noise is a factor
c)
heavy load in a dirty atmosphere
d)
heavy load in a moist atmosphere
8.
A slotted screw at the bottom of the bearing housing is called a ____.
a)
relief plug
b)
purge screw
c)
drain plug
d)
retaining screw
9.
A direct-drive motor is usually connected to a load with a ____.
a)
coupling
b)
cradle mount
c)
rigid base mount
d)
pulley
10.
Grounding straps are required on resilient mounted motors to ____.
a)
ground the motor in case of winding failure
b)
prevent rotation of the motor in the mount
c)
help reduce motor vibration transfer to the object on which the motor is mounted
d)
act as the position for locating the motor leads
11.
The width of a drive belt is classified as ____.
a)
large or small
b)
narrow or wide
c)
both
d)
nether
12.
The alignment of a motor and the driven mechanism must be done at room temperature and ____.
a)
at operating temperature
b)
after heating with a torch
c)
after running for one minute
d)
again after several days of operation
13.
A motor can burn out if the supply voltage is either too high or too low.
a)
True
b)
False
14.
One method a technician can employ to check a motor is to take amperage readings of a motor (both on start-up and after start-up) and compare them to the motor's nameplate.
a)
True
b)
False
15.
A drip-proof motor is designed to prevent any lubricating oil from leaving any of the bearings.
a)
False
b)
True
16.
When oiling a permanently lubricated motor, a 20-weight, non-detergent motor oil should be used.
a)
False
b)
True
17.
Regardless of the type of motor or application, the motor bearings require yearly lubrication.
a)
False
b)
True
18.
There is a definite relationship between the speed of the motor and the speed of the blower.
a)
True
b)
False
19.
The alternating current frequency supplied by the power companies in the United States is ____________________ hertz.
a)
60
b)
80
c)
50
d)
120
20.
If the applied voltage is too high, the motor may develop local hot spots within its windings, but it will not always experience ____________________.
a)
High amperage
b)
Low Voltage
c)
No amperage
d)
No Voltage
21.
The vertical condenser fan is trying to fly downward into the unit to push air out the top, which puts a real load on the end of the bearing, called the ____________________ surface.
a)
Thrust
b)
Rust
c)
Ground
d)
Drive
22.
In order to be electrically safe, a motor that is set in a "resilient" mount, must have a(n) ____________________.
a)
Ground strap
b)
Electrical strap
c)
Voltage strap
d)
Drive strap
23.
Whenever possible, when changing a motor, the _________________________ should be obtained.
a)
Exact replacement
b)
Does not matter
c)
Similar replacement
d)
Drive replacement
24.
The device that transfers the motor's energy to the driven component is called the _________________________.
a)
drive mechanism
b)
power supply
c)
ground strap
d)
transformer
25.
Explain the locked-rotor amperage (LRA).
a)
The LRA is the amperage the motor draws at start-up before the rotor has started to turn.
b)
The LRA is the amperage the motor draws at cool-down before the rotor has started to turn.
c)
The LRA is the amperage the motor draws at start-up after the rotor has started to turn.
d)
The LRA is the amperage the motor draws at cool-down after the rotor has started to turn.
26.
T/F: By taking amperage readings at start-up and while the motor is operating under load and comparing these readings with those on the motor nameplate, the technician can determine whether the motor is operating within its design parameters.
a)
True
b)
False
27.
What is the major advantage of a ball bearing motor over the sleeve bearing motor?
a)
It will handle heavier loads on the bearing.
b)
It will handle lighter loads on the bearing.
c)
It will handle heavier loads on the sleeve.
d)
It will not handle heavier loads on the bearing.
28.
T/F: A motor that is "rigid-mounted" is connected directly to the frame of the equipment and will transmit noise and vibration. A "resilient" mount has a rubber ring that prevents the noise and vibration from transmitting.
a)
True
b)
False
29.
Name four basic methods for mounting motors.
a)
Cradle mount, rigid-base mount, end mount, and belly-band strap mount
b)
Cradle mount, rigid-base mount, front-end mount, and belly-band strap mount
c)
Cradle mount, soft-base mount, end mount, and belly-band strap mount
d)
Cradle mount, rigid-base mount, end mount, and belly-band front mount
30.
A belt-driven blower assembly that has a resilient mounting requires a grounding strap. Why?
a)
It provides a path to ground from the frame to prevent shock should the motor become grounded.
b)
It provides a path to ground from the ground to prevent shock should the motor become grounded.
c)
It provides no path to ground from the frame to prevent shock should the motor become grounded.
d)
It provides a path to ground from the frame to prevent amps, should the motor become grounded.
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