Book #2 Flashcards
The proper treatment for a person who has received a severe electrical shock but still breathing is to:
keep the victim lying down until competent help is available
Two wire control using, for example, a thermostat is known as:
Low-voltage release
Bringing a motor to a quick stop by phase reversal is called?
Plugging
The principle difference between a contactor and a starter is:
The starter has overload relays
What type of diagram includes all of the devices in the system and show their physical relationship to eachother
Wiring diagram
What piece of equipment shall be used to prevent the inadvertent interconnection of normal and standby sources of supply?
Transfer switch
A PN junction is a device known as?
Diode
A rectifier is a device that changes?
AC to DC
A half-wave rectifier produces a:
pulsating DC
A thermistor is a type of resistor whose resistance is dependent on:
Temperature
How does an open-on-rise thermostat work?
temp. rises, contacts open, turns off heating system
What is generated when a thermocouple is generated?
Voltage
The type of motor used by the small motor - driven tool industries is the:
Series Motor
In universal motors, the armature and field coils are connected in?
Series
For what purpose is a heat anticipator on a thermostat
anticipate temperature rises
How does a triac dim an incandescent lamp?
Changing voltage across the lamp
An auto-transformer may be used as:
A motor starter compensator
The correct action to take if a motor trips out the thermal overloads is to:
Allow a cooling period then reset overloads
An AC motor is required to have good variable speed qualities.
Wound rotor
A megger is used for measuring what?
insulation resistance
The centrifugal switch of a single phase capacitor-start induction-run motor is connected:
In series with the start winding
What type of DC motor is used where extremally high torque is required and speed is not important
Series Motor
The proper extinguisher to use on a class āCā fire is:
CO2
Three wire motor control provides?
Low-voltage protection
The range of a voltmeter may be extended by the use of a?
Multiplier in series
An synchronous motor must be started
as an induction motor
The power factor of a synchronous motor can be varied by changing the:
Field excitation
Short-circuited coils in a stator are located efficiently by the use of a:
Growler
The operating relationship of the blower fan in a gas furnace during normal heating operation is:
The fan comes on last and shuts off last
