EIT 250 Final Study Guide

PLC modules _____. A) converts input signals to logic signals B) receives signals from field devices C) provides isolation between field devices and the PLC D) All of the above

D) All of the above

NEMA requires that the motor be able to carry their rated HP at nameplate voltage + or - _____. A) 2% B) 5% C) 8% D) 10%

D) 10%

Generally any voltage above _____ volts is considered dangerous. A) 15 B) 20 C) 25 D) 30

D) 30

Which of the following develop a standard frame size for motors? A) NEMA B) IEC C) IEEE D) A and B

D) A and B

The three distinct windings of a three phase motor are referred to as _____. A) l1 l2 l3 B) phase a, b, c C) phase 1, 2, 3 D) T1 T2 T3

B) phase a, b, c

PLCs were originally designed as replacements for _____. A) analog controllers B) relay control panels C) digital controllers D) microcomputers

B) relay control panels

The two basic parts of a motor circuit are the _______. A) line circuit and the load circuit B) high voltage circuit and low voltage circuit C) control circuit and power circuit D) open circuit and closed circuit

C) control circuit and power circuit

Which of the following should be taken into consideration when determining the location VFD? A) the surrounding environment B) working space C) distance between the motor and the drive D) All of the above

D) All of the above

Flux vector VFDs are classified as ______ types. A) sensor B) sensor-less C) magnetic D) Either A or B

D) Either A or B

A GFCI protects against the most common form of electric shock hazard, the A) line to line short circuit B) static discharge C) ground fault D) overload

C) ground fault

A motor-attached encoder device may be used to provide feedback on the motor's _____. A) speed B) direction C) rotor position D) all of the above

D) all of the above

Single phase motors are _____. A) not as efficient as three phase motors B) not self-starting C) constructed mainly in small horsepower sizes D) all of the above

D) all of the above

An additional On or Start device are wired in _____. A) series B) parallel C) to relays D) to ground

B) parallel

The NEC _____. A) outlines the minimum requirements that must be met for safe wiring installation B) is a manual designed to teach how to properly wire houses C) outlines the ideal requirements for a wiring installation D) both a and c

A) outlines the minimum requirements that must be met for safe wiring installation

If the current in a neutral wire is _____ the current in the hot conductor a ground fault condition exists. A) same as B) twice C) less than D) greater than

A) same as

Solid state relays use _____ as a switching device. A) semiconductors B) coils C) permanent magnets D) contacts

A) semiconductors

A GFI circuit breaker or receptacle monitors _____. A) the current flow through the live conductor B) the current flow in the neutral conductor C) any difference in current flow between a live and a neutral conductor D) the same of the current flow in the live and neutral conductor

C) the difference in current flow between a live and a neutral conductor

According to Ohm's law assuming a body path resistance of 100 Ohm's, what amount of current would flow if a person came in contact with 120 volts? A) 1.2 amps B) 0.833 amps C) 12 milliamps D) 833 milliamps

A) 1.2 amps

The amount of current flowing through a body is equal to _____. A) E/R B) ER C) P/R D) PR

A) E/R

The use of which of the following will increase the distance the motor can be located from a VFD? A) Load reactor B) Fuse protection C) Line reactor D) Circuit breaker protection

A) Load reactor

With low voltage protection motor control _____. A) a power failure disconnects service and when the power is restored manual restarting is required B) a power failure disconnects service and when the power is restored the controller restarts automatically C) only two wires are required for the control device D) both B and C

A) a power failure disconnects the service and when the power is restored manual restarting is required.

An electromechanical relay is basically _____. A) an electromagnet used to switch contacts B) an electromagnet used to operate motors C) an electronic circuit used to control motors D) a device designed to relay information

A) an electromagnet used to switch contacts

The plugging of a motor refers to _____. A) braking by reverse rotation B) momentary operation or small movement of a machine C) automatic restarting of a motor after a power failure D) applying a reduced supply of voltage to a motor during starting

A) braking by reverse rotation

Inverter duty describes a class of motors that are capable of operation _____. A) from a VFD B) from a dc power supply C) for intermittent duty only D) for continuous duty

A) from a VFD

The power supply required to operate a PLC processor and IO modules is _____. A) low voltage DC B) high voltage DC C) low voltage AC D) high voltage AC

A) low voltage DC

On a block diagram the arrows connecting the blocks indicate _____. A) the general direction of the current path B) the wires run between each box C) the current flow from negative to positive D) the current flow from positive to negative

A) the general direction of the current path

On a ladder diagram all wires that connect to a common point are assigned _____. A) the same number B) different numbers C) letters D) all of these

A) the same number

When a current is still applied to an unconscious victim of electrocution, your first priority is to _____. A) turn off the power or separate the victim from the current B) administer artificial respiration C) locate a telephone to call 911 D) loosen any tight portions of clothing

A) turn off the power or separate the victim from the current

Which of the following diagrams shows all of the physical connections of both internal and external wiring involved in the installation of a piece of electrical equipment? A) Diagrams of connections B) Conduit layout C) Plan of circuit diagrams D) Single line diagrams

B) Conduit layout

All facets of the electrical industry apply to the _____ as a minimum standard for the electrical system. A) ABC B) NEC C) PBC D) ANA

B) NEC

Which of the following PLC timers would be used to delay the start of a machine process? A) Retentive timer B) On delay timer C) Off delay timer D) On/Off timer

B) On delay timer

Standard NEMA insulation classes are given by _____. A) number classification B) alphabetic classification C) color classification D) temperature classification

B) alphabetic classification

After vigorous testing to UL standards the product, if it passes, is then referred to as being _____. A) safe B) listed C) certified D) good

B) listed

For an electro-mechanical relay the amount of voltage and current required to energize the relay coil is _____. A) the same as connected to an AC or DC source B) more than that required to de-energize the coil C) the same current and coltage ratings as the contacts D) lass than that required to de-energize the coil

B) more than that required to de-energize the coil

The load carrying capacity of relay contacts is normally given as a current value for a _____. A) inductive load B) resistive load C) capacitive load D) all of the above

B) resistive load

When a split phase motor is operated with a capacitor in series with one of the stator windings the ______. A) starting torque is lower B) starting torque is higher C) starting voltage is lower D) starting voltage is higher

B) starting torque is higher

Contacts of a synchronous clock timer are tripped by _____. A) hand B) tabs set along a timing wheel C) a control signal D) an electromagnet

B) tabs set along a timing wheel

Ladder diagrams show _____. A) the physical location of components B) the electrical connections C) pictorial representations of components D) all of these

B) the electrical connetions

With a current imbalance as low as _____ milliamps a GFCI activates and opens the circuit. A) 1 B) 3 C) 5 D) 7

C) 5

Use a class _____ rated fire extinguisher on energized electrical wiring or equipment. A) A B) B C) C D) D

C) C

Which of the following types program parameters can be changed or adjusted while the drive is running or stopped? A) Configurable B) Read Only C) Turnable on the fly D) Processor firmware

C) Turnable on the fly

Which of the following types of motor starters connects the motor directly to the supply line on starting? A) start stop starter B) jogging starter C) full voltage starter D) reduced voltage starter

C) full voltage starter

The CPU for a PLC _____. A) understands only ladder logic B) serves only to store programs in memory C) looks at the inputs, makes a decision provided by the program, and sets the status of the outputs D) looks at the outputs, makes a decision provided by the program, and setsthe status of the inputs

C) looks at the inputs, makes a decision provided by the program, and sets the status of the outputs

Compared with dashpot timers solid state timers _____. A) are initiated by an electromagnetic coil B) have a narrower timing range C) provide much more accurate timing D) all of the above

C) provide much more accurate timing

To change the direction of a DC motor you _____. A) reverse the armature polarities B) reverse the field polarities C) reverse either of the above D) reverse both of the above

C) reverse either

Which of the following diagrams show an electrical installation reduced to its simplest form? A) wiring diagram B) ladder diagram C) single line diagram D) pictorial diagram

C) single line diagram

A motor nameplate indicates that a motor has a service factor of 1.25, this means that the _____. A) the normal run time service time intervals can be increased by 125% B) the cost of operating a motor is 125% higher than an equivalent motor rated for a service factor of 1 C) the motor can on occasion safely develop 125% of its rated HP D) a motor can safely be operated 125% of its rated voltage continuously

C) the motor can on occasion safely develop 125% of its rated HP

The speed of an AC induction motor depends on _____. A) the frequency of the electrical power supply B) the voltage of the electrical power supply C) the number of poles in a motor D) A and C

D) A and C

Which of the following motor nameplate data may be programmed into a VFD? A) speed B) full load current C) voltage D) All of the above

D) All of the above

The electric shock intensity ____. A) increases with an increase of current flow B) increases with the length of time to exposure C) is determined in part by the path the current takes through your body D) All of the above

D) All of the above.

PLC timers: A) Input instructions B) Output instructions C) Provide the same functions electro-mechanical relays D) Both B and C

D) Both B and C

A motor starter is an electric controller used to _____ a connected motor. A) start B) stop C) protect D) all of the above

D) all of the above

The purpose of bonding non-current carrying metal parts of an electrical system is to _____. A) establish a low resistance path for fault current B) facilitate the operation of over-current protection devices C) limit the touch of voltage when the metal parts are energized by a ground fault D) all of the above

D) all of the above

When operating a disconnect switch _____. A) be sure it is not under a load B) stand clear of the box C) face away while operating the switch D) all of the above

D) all of the above

An overhauling load A) results in generator action within a motor B) occurs whenever the inertia or the load is less than that of the motor rotor C) occurs whenever the inertia of the load is more than that of the motor rotor D) both a and C

D) both a and C

The speed of an induction motor depends on the _____. A) number of poles built into the motor B) frequency of the power supplied to it C) type of braking system employed D) both a and b

D) both a and b

From a safety standpoint, only ______ push-buttons should be utilized for motor stop buttons. A) illuminated B) non-illuminated C) normally opened D) normally closed

D) normally closed

With a selector switch a _____ actuates the contacts. A) plunger B) button C) relay D) rotating handle

D) rotating handle

In dual voltage, split phase motors the two windings are connected in _____for the high voltage operation. A) Wye B) Delta C) parallel D) series

D) series