Ch9 Generating Electricity

6. Technician A says the current that is induced when the magnetic field of a wire coil collapses after a circuit is opened has a much lower voltage than the voltage in the closed circuit. Technician B says any coil of wire in an electrical system can produce hundreds of volts when it is de-energized. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B

6.

6. Which of the following devices uses galvanic reactions to produce electric current? A. Alternators B. Batteries C. Solar cells D. Piezoelectric crystals

6.

7. Technician A says the principle of producing electrical current flow using electromagnets is known as electromagnetic induction. Technician B says alternators, generators, and speed sensors use this electrical principle to produce electrical current. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B

7.

8. Technician A says suppression of the voltage spike from magnetic coils is accomplished using diodes, capacitors, resistors, or induction coils. Technician B says without suppression, the voltage spike can travel to other circuits connected to the coil damaging sensitive electronic components. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B

8.

9. Technician A says the primary winding is where current is induced in a step-up transformer. Technician B says the secondary winding is supplied current to step-down voltage. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B

9.

Electromagnet

A conductor wound into a coil that produces a magnetic field when current flows through it.

Magnetism

A fundamental force that can be used to push or pull electricity.

Thermocouple

A thermoelectric device consisting of two dissimilar metals that produce voltage when heated.

Step-up transformer

A transformer used to increase the voltage from a primary coil's lower input voltage.

Step-down transformer

A transformer used to reduce primary coil voltage in the secondary coil. A battery charger would use a step-down transformer to change 120-volts AC into 12 volts AC.

Piezoelectric effect

A type of electricity produced by bending or squeezing a unique type of quartz crystal.

10. Which induction principle does a transformer use to change voltage? A. Self-induction B. Electromagnetic induction C. Mutual induction D. Reactive inductance

A. Self-induction

1. Which one of the following energy sources is used by a "pyrometer' to move electrons? A. Friction B. Heat C. Magnetism D. Induction

B. Heat, p

2. Technician A says solar cells can produce electricity are widely used in commercial vehicle applications. Technician B says commercially available cells are used as trickle chargers for batteries. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B

B. Tech B.

Magnetic field strength of an electromagnetic is calculated

By multiplying the amperage times the number of turns in the wire. The units of magnetic field strength are amps-turns.

5. Which of the following sources of energy is used to produce static electrical charge? A. Heat B. Light C. Friction D. Pressure

C.

7. Why should fuel tankers and tankers carrying powders ( cement, flour) be grounded before removing product? A. To add missing electrons to the tanker body B. To remove excess electrons from a tanker body C. To minimize the likelihood of a spark when the product is transferred. D. To prevent generating electric current form mutual induction.

C.

9. Which of the following best describes what a material with high "reluctance" is most capable of doing? A. Passing electric current B. Conducting magnetic fields C. Resisting conduction by magnetic fields. D. Resisting electric current.

C. Resisting conduction by magnetic fields.

Magnetic induction involves moving a conductor across a magnetic field t induce current flow. Similarly, magnetic induction

Can take place by moving a magnetic field across a conductor, such as a stationary coil of wire.

If continuous duty relays are used in place of intermittent duty relays, they will

Chatter when voltage drops such as when the starter motor cranks an engine. Intermittent duty relays will overheat and quickly burn-out when used in place of continuous duty relays.

Self-induction is observed in a current-carrying coil when the current in the wire is changing. Expanding or

Collapsing a magnetic field self-induces current flow in the coil. In self-induction, no separate magnetic field, like a permanent magnet or separate electromagnet, is used.

If two different metals are joined and heated, a small

Electric current can be generated. This system is a thermoelectric source of energy.

Magnetic fields made from coils of wire having thicker wire but

Fewer turns conduct more amperage, remain stronger, and are less sensitive to voltage drop than coils made from thinner wire with more turns having the same amp-turn strength.

Fuel cells are a type of electrochemical device that combines

Hydrogen and oxygen to produce water and, in the process, it produces electricity and heat.

Mutual induction involves two coils or conductors with a changing magnetic field

In one producing a movement of electrons in the other. Step-up and step-down transformers use mutual induction, plus a turn ratio difference between the primary and secondary coil windings.

Photo-voltaic energy is produced from converting

Light to electricity. Solar cells are an example of photo-voltaic energy.

Static electricity can be induced by rubbing or separating two materials on opposite sides of the tribo-electric series. During this process, one material

Loses electrons to the other, to create positive and negative static (stationary) charges.

Secondary winding

The coil of wire where voltage is induced through mutual induction in a step-up or step-down transformer.

Photovoltaic effect

The conversion of light into electricity.

Primary winding

The electromagnetic coil of wire which creates the magnetic field in a step-up or step-down transformer.

Electromagnetic induction

The production of an electrical current in a conductor when it moves thru a magnetic field or a magnetic field moves past it.

Galvanic reactions producing electricity are the result of

Two dissimilar metals being immersed in an electrical conductive liquid called an electrolyte.

Twisting the data bus wire lines helps to reduce the signal noise from electromagnetic interference produced from mutual induction.

Electromagnetic interference, is cancelled by loops in front or behind the loop with induced current.

Electricity can create magnetic effects called

Electromagnetism. these magnetic forces can be used to create mechanical movement, such as in a relay or electric motor.

Piezoelectric materials have a polarity and can

Expand or contract when current passes through them.

Self-induction in electromagnetic coils produces

Potentially damaging high voltage spikes and must be suppressed with diodes, resistors, capacitors, and induction coils.

The piezoelectric effect creates electricity when crystals like

Quartz are subjected to mechanical stress like bending or squeezing.

Friction, heat, chemicals, light, pressure, and magnetic induction are all

Sources of electricity. Each of these types of energy can move electrons so they can do work.

5. Technician A says piezo ceramic injectors can operate faster that injectors with electromagnetic actuators. Technician B says magnetic fields can build up faster in a piezo-ceramic actuator. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B

5.

Fuel cell

An electrochemical device that combines hydrogen and oxygen to produce electricity, heat, and water.

The three basic elements to a fuel cell are the

Anode, the cathode, and the electrolytic membrane.

Continuous duty relays use magnetic coils made from

Thinner wire with more turns than intermittent duty relays with fewer turns and thicker wire.

8. When handling sensitive electronic parts, which is the best practice a tech should follow to prevent electrostatic damage? A. Ground the truck-bus chassis. B. Remove electronic parts wrapped in Mylar packaging ASAP. C. Wear a copper wrist bracelet. D. Momentarily touch a metal door-handle or chassis part before handling parts.

D.

Which of the following electromagnets has a stronger magnetic field? A. One wound with 100 turns of wire and 1 amp of current. B. One wound with 750 turns of wire and 0.1 amp of current. C. One wound with 500 turns of wire and 0.1 amps of current. D. One wound with 75 turns of wire with 1.5 amps of current.

D.

1. Technician A says electric charges are produced when two different materials are separated. Technician B says static electricity is another name given to tribo-electricity because objects can develop stationary high voltage charges from friction. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B

1.

4. Technician A says one of the most common ways electricity is produced in a heavy-duty vehicle is thru the use of the energy found in magnetic fields. Technician B says magnetism is the force which attracts or repels electric charges. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B

4.

10. Technician A says dozens of varieties of fuel cells exist, but they all fundamentally work in the same manner. Technician B says like a battery, a fuel cell requires recharging. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B

10.

3. Technician A says thermoelectric devices (TEDs) are solid-state heat pumps formed form several layers of semiconductor materials. Technician B says TEDs are used for cooling or heating small areas, including seats, steering wheels, cup-holders, or beverage storage compartments. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B

3.

3. Which of the following types of induction can cause a large spark after a coil of wire is disconnected from a power source? A. Self-induction B. Mutual induction C. Cross-talk induction D. Magnetic reluctance

3.