EMC Chapter 7

Question 1

A(n)___ is a magnet whose magnetic energy is produced by the flow of electric current.

Answer 1

electromagnet

Question 2

An electromagnet consists of an ___ core inserted into a coil.

Answer 2

iron

Question 3

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.

Answer 3

north

Question 4

An electromagnet’s strength can be controlled by regulating its ___.

Answer 4

electric current

Question 5

The strength of a magnetic field and current are ___ related.

Answer 5

directly

Question 6

A(n)___ is the movable part of a solenoid.

Answer 6

armature

Question 7

There are ___ different solenoid configurations.

Answer 7

five

Question 8

A ___ solenoid uses a lever attached to an armature to transform the armature’s vertical action into a horizontal action.

Answer 8

bell-crank

Question 9

___ current is unwanted current induced in the metal structure of a device due to the rate of change in the induced magnetic field.

Answer 9

Eddy

Question 10

A(n)___ coil sets up an auxiliary magnetic field that helps hold in the armature as the main coil magnetic field drops to zero in an AC circuit.

Answer 10

shading

Question 11

A ___ is an electric output device that coverts electrical energy into a linear mechanical force

Answer 11

solenoid

Question 12

A(n)___ is a single turn of conducting material (normally copper or aluminum) mounted on the face of the magnetic laminate assembly or armature of a solenoid.

Answer 12

shading coil

Question 13

Magnetic coils are normally constructed of many turns of insulated ___ wire wound on a spool.

Answer 13

copper

Question 14

In a solenoid coil, the inrush current is approximately ___ times the sealed current.

Answer 14

6 to 10

Question 15

The magnetic opposition upon energizing a solenoid is referred to as ___ reactance or total impedance.

Answer 15

inductive

Question 16

Magnetic coil data is normally given in ___.

Answer 16

volt amperes

Question 17

___ voltage is the minimum voltage that causes the armature to start to move.

Answer 17

Pick-up

Question 18

For most solenoids, the minimum pick-up voltage is about ___ of the solenoid rated voltage.

Answer 18

80% to 85%

Question 19

Drop-out voltage can be as low as ___% of the solenoid rated voltage.

Answer 19

70

Question 20

___ variations are one of the most common causes of solenoid failure.

Answer 20

Voltage

Question 21

A solenoid’s ___ is usually given in operations per minute.

Answer 21

duty cycle

Question 22

___ voltage is the minimum control voltage required to cause the armature to seal against the pole faces of the magnet.

Answer 22

Seal-in

Question 23

A ___ control valve is a valve that is used to direct the flow of fluid throughout a fluid power system.

Answer 23

directional

Question 24

A ___ is the number of locations within the valve in which the spool can be placed to direct fluid through the valve.

Answer 24

position

Question 25

A ___ is a flow path through a valve.

Answer 25

way

Question 26

___-way valves are used as shutoff, check, and quick-exhaust valves.

Answer 26

Two

Question 27

___ use fluid power, cylinders, actuators, and grippers to provide the required power and movement.

Answer 27

Industrial robots

Question 28

___ are used to help determine the cause of solenoid failure.

Answer 28

Manufacturer charts

Question 29

The voltage applied to a solenoid should be +-___% of the solenoid rated value.

Answer 29

10

Question 30

A ___ circuit is a circuit that suppresses noise and high voltage on the power lines.

Answer 30

snubber

Question 31

A solenoid ___ when the voltage is excessive.

Answer 31

overheats

Question 32

A solenoid draws ___ current when first connected to power.

Answer 32

several times its rated

Question 33

Solenoids usually fail due to electrical problems or ___.

Answer 33

mechanical damage