3B Midterm Prep Flashcards
Overload relay devices are normally rated to trip at specific current when surrounded by an ambient temperature of ___ AC.
40
A ___ is a device used only periodically to remove electrical circuits from their supply source.
Disconnect
___ overload relays are extremely quick to reset because they do not require a cooling-off period before being reset.
Magnetic
Originally, most knife switches were made of ___, which required replacement after repeated arcing, heat generation, and mechanical fatigue.
copper
Two-wire control is normally used for ___ installations where an immediate return to service after a power failure is required.
Remote or inaccessible
One method that can be used to determine whether a transformer has failed is to measure the input and output ___.
voltages
To obtain a control voltage of 120 VAC from a line voltage of 480 VAC, the two primary coils must be connected in ___.
series
Transformers are used to increase generated ___ to a high level for transmission across the country and then decrease it to a low level for use by electrical loads.
voltage
Low voltage transformer windings are marked with an ___.
X
A ___ is a connection brought out of a winding at a point between its endpoints to allow the voltage or current ratio to be changed.
Tap
In a delta-connected system, ___ of the three wires are normally connected to ground.
none
Voltage between any two lines in a wye-connected AC generator is ___ multiplied by any of the individual phase voltages.
1.73
A(n) ___ connection is a connection that has each coil end connected end-to-end to form a closed loop.
delta
Each complete rotation of the ___ in a single phase (one wire) AC generator produces one complete alternating current cycle.
armature
The three ends of a wye-connected AC generator can be safely connected at the ___ point because no voltage difference exists between them.
neutral
A brush is the sliding contact the rides against the commutator segments or slip rings and is used to connect the ___ to the external circuit.
armature
A(n) ___ is the movable coil of wire in a generator that rotates through the magnetic field.
armature
Field windings are electromagnets used to produce the ___ field in a generator.
magnetic
Commutator segments reverse the connections to the brushes every ___ cycle.
half
A shunt-wound generator is a generator that has its field windings connected in ___(shunt) with the armature and the external circuit (load).
parallel
All contacts can have a maximum of ___ break(s).
two
Relays are available with 1 to ___ poles.
12
Typical ___ life ratings are 100,000 to 500,000 operations.
contact
Sulfidation increases the ___ of the contacts.
Resistance
A ___ relay is a fast-operating single-pole, single-throw switch with normally open contacts hermetically sealed in a glass envelope.
Reed
A ___ is a flow path through a valve.
way
Solenoids usually fail due to electrical problems or ___
mechanical damage
Magnetic coils are normally constructed of many turns of insulated ___ wire wound on a spool.
copper
The left-hand rule states that if the fingers of the left hand are wrapped in the direction of the current flow of the coil, the thumb points to the magnetic ___ pole of the coil.
north
For most solenoids, the minimum pick-up voltage is about ___ of the solenoid rated voltage
80%-85%
A(n) ___ system is not a common application of temperature switches.
Air compression
A ___ is not a basic actuator used on limit-switches.
contact pole
A ___ level switch detects the dielectric variation when a product is in contact with the probe and when the product is not in contact with the probe.
capacitive
A(n) ___ is the part of a switch that includes the written description of the switch’s operation
legend plate
A ___ is not a common foot switch application
two hand safety circuit
The dashed line method works well when the control contacts are close together and the circuit is relatively ___.
simple
The ___ gate is a universal building block of digital logic
NAND
No more than ___ load(s) should be placed in any circuit line between the power lines L1 and L2
one
Additional start pushbuttons are connected in parallel using ___ logic with the existing start pushbuttons
NOR
Two loads must not be connected in ___ in one line of a line diagram
series
Electrical power must be ___ when electrical equipment is inspected, serviced, or repaired.
removed
A(n) ___ signal word is used to indicate an imminently hazardous situation which, if not avoided, will result in death or serious injury
danger
___ is the process of removing the source of electrical power and installing a lock which prevents the power from being turned on.
lock out tag out
A(n)___ is a temporary or movable platform or structure for works to stand on
scaffold
___ injuries suck dick and are the result of improper lifting procedures
back
A(n) ___ is a device that detects insulation deterioration by measuring high resistance values under high test voltage conditions
megohmmeter
Always check for the presence of ___ before taking any measurements.
voltage
in most cases, diodes are tested with a ___
digital multi meter
A(n)___ is a test instrument that provides a visual display of voltages
oscilloscope
A ___ tester is a device that indicates approximate voltage level and type (AC or DC) by the movement and vibration of a pointer on a scale.
voltage
A ___ is a diagram that shows a logical sequence of steps for a given set of conditions
flow chart
A(n)___ indicates the beginning and end of a flow chart or section of a flow chart
ellipse
A(n) ___ is a material that has very little resistance to current flow and permits electrons to move through it easily
conductor
A(n) ___ is a letter or combination of letters that represents a word
abbreviation
The primary function or a ___ diagram is to show how the distinct parts of a system relate
block
The unit of capacitance
farads
The electrical term used to describe the opposition to electron flow is ___
resistance
Ohm’s law is used in circuits that contain ___
impedance
A(n) ___ is an electronic component that allows current to pass through it in only one direction.
diode
___ power is power absorbed and returned to a load due to its inductive and/or capacity properties.
Reactive
