ELECTRICAL. CDTA Technical Training Center

Transcription

1 ELECTRICAL

2 ATOMIC STRUCTURE Protons positive charge Electron negative charge Neutron - neutral Electricity is the movement of electrons from atom to atom

3 ELECTRON FLOW CONDUCTOR - Materials which have extra electrons that will move freely Gold, silver, copper, lead INSULATOR - Materials that do not allow for free electron movement Glass, plastic, rubber SEMI-CONDUCTOR - Material which has some properties of a conductor and some properties of an insulator An example would be a diode

4 BASIC PROPERTIES OF ELECTRICITY LIKE CHARGES REPEL OPPOSITE CHARGES ATTRACT

5 ELECTRICAL THEORY ELECTRON THEORY Electrons flow negative to positive CONVENTIONAL THEORY Electrons flow positive to negative

6 Current Flow Theories Conventional Theory _ + Electron Theory

7 ELECTRICAL MEASUREMENTS VOLTAGE Force that causes electron flow EMF, push, pressure, potential difference Symbol E Unit of measurement V Checking voltmeter ; use leads in parallel with source.

8 ELECTRICAL MEASUREMENTS AMPERAGE Rate of current flow through a conductor. Intensity, flow, current Symbol I Unit of measurement A Checking ammeter ; use leads in series with circuit (or inductive pick-up) Note; wire gauge is determined by amperage draw.

9 ELECTRICAL MEASUREMENTS RESISTANCE The opposition to current flow through a conductor. Symbol R Unit of measurement ohms Checking ohmmeter; connected in a series loop of an isolated circuit or component. Note circuit must contain no voltage when checking resistance

10 ELECTRICAL MEASUREMENTS RESISTANCE The opposition to current flow through a conductor Infinity open circuit; no current flow Low resistance short; high current flow High resistance corrosion; low current flow

11 LAWS OF ELECTRICITY VOLTS = AMPS x OHMS (Ohms Law) ELECTRONS TAKE THE PATH OF LEAST RESISTANCE ELECTRON FLOW THROUGH A CONDUCTOR WILL CREATE A MAGNETIC FIELD WATTS = AMPS x VOLTS

12 Types of Current Direct current (DC) electron flow in one direction only Alternating current (AC) electron flow changes direction many times per second

13 CURRENT FLOW TYPES OF CIRCUITS Series circuit Parallel circuit Series parallel circuit

14 CURRENT FLOW SERIES CIRCUIT All controls and current consuming devices are connected in a single line. One path from source through loads to ground Volt

15 OHMS LAW If two values are known in a circuit, the remaining value can be found using ohms law E=IxR I=E/R R=E/I I E R

16 CURRENT FLOW SERIES CIRCUIT LAWS Connecting loads in series Voltage drops across loads Amperage remains constant Resistances are added

17 Series Circuit 12 Volt - + Fuse 1 OHM 3 OHM

18 CURRENT FLOW PARALLEL CIRCUITS Devices are connected in a parallel line providing several current paths to ground. - + Fuse 12 Volt

19 CURRENT FLOW PARALLEL CIRCUIT LAWS Loads connected in parallel Voltage remains constant Amperages are added Resistance is divided

20 Parallel Circuit - + Fuse 12 Volt 1 OHM 3 OHM

21 CURRENT FLOW SERIES PARALLEL CIRCUITS Combination of each type of current path Rules of each circuit apply 12 Volt - + Fuse Rheostat (Variable resistor)

22 OHM S LAW VISUALIZED Amperage and Resistance 12V High Resistance Voltage Constant Low Current Flow

23 OHM S LAW VISUALIZED Amperage and Resistance 12V Low Resistance Voltage Constant High Current Flow

24 OHM S LAW VISUALIZED Amperage and Voltage 16V Resistance Constant High Voltage High Current Flow

25 OHM S LAW VISUALIZED Amperage and Voltage 9V Resistance Constant Low Voltage Low Current Flow

26 CIRCUIT MALFUNCTIONS OPEN CIRCUIT SHORT CIRCUIT GROUNDED CIRCUIT

27 CIRCUIT MALFUNCTIONS OPEN CIRCUIT SHORT CIRCUIT GROUNDED CIRCUIT - + Fuse 12 Volt

28 CIRCUIT MALFUNCTIONS OPEN CIRCUIT SHORT CIRCUIT Fluke Fluke 4 1 OHMS OHMS

29 CIRCUIT MALFUNCTIONS OPEN CIRCUIT SHORT CIRCUIT GROUNDED CIRCUIT - + Fuse 12 Volt

30 CIRCUIT MALFUNCTIONS Shorted or grounded components can damage circuits due to additional current flow. To protect circuits, fuses or circuit breakers are used

31 CIRCUIT PROTECTION FUSE A thin metal strip designed to break (open) at a specific current draw. Once a fuse is blown (opens) it must be replaced Fuses come in various amperage ratings USE CORRECT FUSE

32 FUSE TYPES

33 FUSE RATING

34 CIRCUIT PROTECTION CIRCUIT BREAKER Uses a heat sensitive bi-metallic strip designed to break contact in an overload condition. Circuit breakers can be manual reset or auto reset. When replacing a circuit breaker use correct rating.

35 WIRE GAUGE RATING A.W.G. American Wire Gauge The higher the number the smaller the diameter of the wire. Large diameter = less resistance Smaller diameter = more resistance 10 Gauge 18 Gauge

36 ELECTRICAL COMPONENTS BATTERIES Purpose Energy for cranking Supply current when demand exceeds output of charging system Stabilize voltage/dampen voltage spikes

37 ELECTRICAL COMPONENTS BATTERIES SAFETY While charging, batteries produce hydrogen gas that WILL EXPLODE if exposed to open flame or spark Acid will burn Protect eyes, skin, and clothing

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39 ELECTRICAL COMPONENTS BATTERIES Construction Hard plastic case Plates; made of lead alloy Positive plate lead peroxide Negative plate sponge lead Separator plate - PVC

40 ELECTRICAL COMPONENTS BATTERIES Cell Construction Negative and positive plates alternate; there is one more negative plate to occupy the exposed end of each group. 4D battery has 19 plates per cell. 8D battery has 27 plates per cell. Each cell is filled with electrolyte

41 ELECTRICAL COMPONENTS BATTERIES Construction Electrolyte; a solution that consists of sulfuric acid in water 64% water + 36% acid = electrolyte

42 ELECTRICAL COMPONENTS BATTERIES Each cell will produce approximately 2.2 volts Six cells connected in series will produce a 12 volt battery (13.2 volts)

43 ELECTRICAL COMPONENTS BATTERY RATINGS Cold Cranking Amps (CCA) cranking current available at 0 degrees 8D battery = 900 CCA 4D battery = 550 CCA Amp Hours (AH) Amp hours is determined by placing a specific load on a battery and measuring the time required for it to discharge

44 ELECTRICAL COMPONENTS BATTERY CHARGING Restores the active chemicals of the plates and the electrolyte to their original condition, by feeding direct current to the cell.

45 ELECTRICAL COMPONENTS BATTERY CHARGING Connecting a charger Red clamp to positive terminal Black clamp to negative terminal NOTE when disconnecting batteries remove negative cable first; when connecting cables connect negative last.

46 ELECTRICAL COMPONENTS Battery Tests Specific gravity Load test

47 ELECTRICAL COMPONENTS Specific Gravity The weight of a substance in relation to that of water Affected by temperature For every 10* F above 80* add.004 pts. For every 10* F below 80* subtract.004 pts. Measured at each cell with hydrometer Indicates a cell s STATE OF CHARGE

48 ELECTRICAL COMPONENTS BATTERY TESTING Hydrometer; An instrument that measures the specific gravity of electrolyte is full charge at 80* F.025 difference between cells indicates a defective battery.

49 ELECTRICAL COMPONENTS Load Test A carbon pile load is connected to a fully charged battery for 15 seconds and minimum voltage is recorded The load is equal to 1/2 the CCA rating of the battery Minimum voltage is affected by temperature Checks WORK CAPABILITY of the battery

50 ELECTRICAL COMPONENTS Load Test Minimum Voltages Temp. Min. Volts 70* * * * * * * 8.7 0* 8.5

51 ELECTRICAL COMPONENTS BATTERY MAINTENANCE Check battery state of charge (hydrometer) Clean terminals and battery casing Check work capability (load test) Check cables for stiffness Check battery hold downs

52 WATTS LAW Watts law is used to determine power availability and usage Watts = Amps x Volts

53 WATTS LAW Power sources connected in SERIES Positive to Negative Voltages are added Amperage remains the same Volt 12 Volt = 9600 WATTS 400 AMPS 400 AMPS 24 VOLTS / 400 AMPS 24v x 400a = 9600 Watts

54 WATTS LAW Power sources connected in PARALLEL Positive to positive; negative to negative Voltage remains the same Amperages are added Volt 12 Volt = 9600 WATTS 400 AMPS 400 AMPS 12 VOLTS / 800 AMPS 12v x 800a = 9600 Watts

55 WATTS LAW Volt 12 Volt = 9600 WATTS 400 AMPS 400 AMPS 12 VOLTS / 800 AMPS 12v x 800a = 9600 Watts Volt 12 Volt = 9600 WATTS 400 AMPS 400 AMPS 24 VOLTS / 400 AMPS 24v x 400a = 9600 Watts

56 RELAYS Another name for a relay is a magnetic switch Relays are 12 or 24 volts Relays normally have 5 posts and are 85,86,87,87a and and 86 is power and ground, 87 and 87a is the switch, 30 is power

57 RELAY OPERATION Volt 86 87a

58 RELAY OPERATION Volt 86 87a

59 RELAY OPERATION Volt 86 87a

60 RELAY OPERATION Volt 86 87a

61 RELAY OPERATION Volt 86 87a

62 RELAY OPERATION Volt 86 87a

63 RELAY OPERATION Volt 86 87a

64 RELAY OPERATION Volt 86 87a

65 RELAY OPERATION Volt 86 87a

66 RELAY OPERATION Volt 86 87a

67 RELAY OPERATION Volt 86 87a

68 RELAY OPERATION Volt 86 87a

69 RELAY OPERATION Volt 86 87a

70 RELAY OPERATION Volt 86 87a

71 RELAY OPERATION Volt 86 87a

72 RELAY OPERATION Volt 86 87a

73 RELAY Relays are 12 or 24 volt Volt Volt 86 87a 87 Determined by voltage placed on coil Volt bulb Volt 24 Volt 86 87a Volt bulb

74 ELECTRICAL COMPONENTS CHARGING SYSTEM ALTERNATOR; Theory & operation REGULATOR; Theory & operation

75 ELECTRICAL COMPONENTS CHARGING SYSTEM CHECKING AND ADJUSTING ALTERNATOR OUTPUT FULL FIELDING THE ALTERNATOR

76 ALTERNATOR OUTPUT TEST Carbon Pile Load AMPS REGULATOR F B I Ignition AMMETER 12 Volt 24 Volt 27.5 VOLTMETER F1 12V Relay F2 ALTERNATOR

77 50 DN ALTERNATOR F1 Terminal F2 Terminal 12 Volt relay terminal

78 VOLTAGE REGULATOR Controls output of alternator by controlling the strength of the field coil Constantly monitors system voltage & adjusts magnetic field accordingly Stronger field Higher output Weaker field Lower output

79 NOT CHARGING Neoplan - Off 24 V 12 V GND To 12 Volt circuits Volt Volt REGULATOR F B I 101 CIRCUIT CB 100 Circuit 85 87a 87 Climate Control F1 F2 12V Relay ALTERNATOR 101 Circuit Alternator indicator light F1 F2

80 CHARGING 24 V 12 V Neoplan - Charging GND To 12 Volt circuits Volt Volt REGULATOR F B I 101 CIRCUIT CB 100 Circuit 85 87a 87 Climate Control F1 F2 12V Relay ALTERNATOR 101 Circuit Alternator indicator light John Miller

81 FLOW CHART

82 ELECTRICAL SYMBOLS

83 CURRENT FLOW SERIES CIRCUITS Connecting sources (batteries) in series Voltages are added Amperage remains constant

84 CURRENT FLOW PARALLEL CIRCUITS Connecting sources in parallel Voltage remains constant Amperage is added