Instructor Name Your Name 16 CHAPTER Learning Objectives Describe the construction of storage batteries Work safely around storage batteries Explain the two different ways in which batteries may be shipped from the manufacturer ID: 525407
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Truck Trailer Refrigeration Electrical Components
Instructor Name: (Your Name)
16
CHAPTERSlide2
Learning Objectives
Describe the construction of storage batteriesWork safely around storage batteriesExplain the two different ways in which batteries may be shipped from the manufacturer
Describe the three different types of batteries used today and how maintenance is performed on themExplain how batteries are rated
Describe storage procedures for batteriesExplain testing procedure to ensure batteries can perform to rated performance levelSlide3
Learning Objectives (continued)
Describe how a battery should be charged and list the steps involved in jump-starting a unit with a low batteryList the steps in removing and replacing a batteryExplain the function of the charging system
List the major components of a typical alternator and the function of the partsExplain the function of a voltage regulator
Describe the steps of an alternator output testSlide4
Learning Objectives (continued)
List the steps involved in removing and replacing an alternatorDescribe the two styles of starters used in the transportation refrigeration industry
Explain the purpose of an overrunning clutchDescribe the steps involved in performing a starter testExplain the purpose of the various truck refrigeration safety switchesSlide5
Battery Construction
Case filled with diluted solution of sulfuric acid and waterPositive and negative electrodes in the form of platesPlates composed of lead or lead derived material
Batteries are divided into several cells, 6 cells for a 12 volt batterySlide6
Typical Battery Slide7
Cell Operation
When two dissimilar metals are placed in an acid bath, an electrical potential is produced across the polesVoltage is produced due to a reaction between the plates and the electrolyteThe positive plate is composed of lead peroxideThe negative plate is composed of sponge leadElectrolyte is a solution of water and sulfuric acidSlide8
Cell Operation (continued)
Six cell elements in a 12 volt batteryEach cell produces approximately 2.1 volts regardless of size and number of platesCells are connected in series to produce 12.6 voltsSlide9
Single Battery CellSlide10
Battery With Six CellsSlide11
Battery Safety
Keep flames and sparks away form batteries, do not smoke near batteriesWear eye protection and rubber gloves to protect from chemical burnsNever connect or disconnect live circuits. Always turn off unit, battery charger or tester when attaching or removing leads
Batteries should always be installed in a vented battery box to vent hydrogen gas while chargingSlide12
Battery Safety (continued)
Work in a well vented area when charging batteriesAlways keep the battery upright to prevent spilling electrolyteNever work alone on batteries, in case of accidentSlide13
CAUTION
Battery electrolyte contains sulfuric acid, which can cause severe personal injuries (burns) and damage to clothing and equipment. If electrolyte is spilled or splashed on a person’s body or clothing, it must be immediately neutralized by washing with a solution of baking soda and water. The solution should be 0.25 pounds baking soda to 1 quart of water.
Electrolyte splashed into the eyes is extremely hazardous. The eyes should be immediately held open and flushed with cool clean water for about 5 minutes, then seek medical treatment at once.Slide14
Battery Types; Conventional
Require the most maintenanceWater in electrolyte turns to a gas and must be replenishedUse only distilled water when filling a battery
Water level should be no higher than 1/8” (3.2 mm) below vent wellDamage can occur if electrolyte level drops below top of cell plates
Over filling can weaken electrolyte solution and batterySlide15
Battery Types; Conventional (continued)
Vaporized electrolyte can condense on top of case and discharge batteryVaporized electrolyte can condense on top of case and corrode terminal and cablesConventional batteries are easily overcharged
Conventional batteries perform well in a deep cycle applicationSlide16
Correct Electrolyte LevelSlide17
Low Maintenance Batteries
Less maintenance then conventional batteriesLess electrolyte gasificationLess corrosion of terminalsMore resilient to over charging
Shorter life in a deep cycle applicationSlide18
Maintenance Free Batteries
Designed to not require electrolyte replenishment under normal operating conditionsTerminal and cable ends almost maintenance free Generally require higher voltage regulator settings then conventional and low maintenance batteriesSlide19
Battery Ratings CCA
Performance rated by their cold cranking amps (CCA) designationLoad in amperes a battery can sustain for 30 seconds @ 0⁰ F (-17.8⁰ C) and not fall below 1.2 v per cell or 7.2 v on a 12 v batteryCCA indicates how much power a battery can deliver in extremely cold conditionsSlide20
Cold Weather Effects on BatterySlide21
Battery Ratings; Reserve Capacity
The number of minutes a new fully charged battery at 80⁰F (26.6⁰C) can sustain a load at 25 amperes before battery voltage drops to 1.75 V per cell or 10.5 V for a 12 V battery.Reserve capacity indicates how long a battery can provide enough power to keep ignition, head and tail lights, windshield wipers, and heater operating if charging system failsSlide22
Battery Rating; BCI Number
Battery Council International (BCI) a number indicates batteries physical dimensionsBCI number indicates the height, width, and lengthBCI number is no indication of the batteries performance capacity
A batteries performance characteristic is determined by internal componentsSlide23
BCI Battery DimensionsSlide24
Battery Maintenance
Check for loose terminalsCheck for cracked or broken caseIf case is broken replace immediately
Inspect case for dirt, moisture, and corrosionClean case and terminals with baking sodaBattery cable should be checked for cleanliness and tightness
Check electrolyte level, add water if lowNote:
Even maintenance free batteries electrolyte levels should be checked monthlySlide25
Hydrometer Testing
Hydrometer tests the state of charge by measuring the specific gravity of electrolyteA fully charged battery will have a specific gravity of 1.265 at 80⁰F (26.7⁰C)A hydrometer must be temperature compensated, add .004 for every 10⁰ above 80⁰F and subtract .004 for every 10⁰ below 80⁰F Slide26
Hydrometer ReadingSlide27
Refractometer Testing
No temperature compensation neededWear eye protection when using refractometerExtract a drop of electrolyte, place on lens of refractometer
Hold meter up to light and view readings
Electrolyte Reading
Reading
% Charge
1.260
100
1.230
75
1.200
50
1.100
0Slide28
Open Circuit Voltage Test
Determines battery state of chargePerformed when battery is at rest, no loadRemove surface charge prior to test
Meter Reading
Battery Condition
12.66 Fully
Charged
12.48
75
% Charge
12.30
50
% Charge
11.76
0%
ChargeSlide29
Battery Load Test
Load test gives true measurement of a batteries ability to performBattery must be fully chargedLoad to 50% of rated CCA
Hold load for 15 secondsBattery voltage should not drop below 9.6V at 70⁰F (21⁰C
)Replace battery if it falls below minimum specificationsSlide30
Jump Starting
Connect to positive terminal of stalled batteryConnect to positive terminal of jumper batteryConnect to negative terminal of jumper battery
Connect to good chassis ground on stalled vehicle away form batteriesDisconnect jump cable exact reverse order used to connect themSlide31
Alternator Components
StatorThree individual windings in a ring made of ironElectrical impulses occur at different times to produce three phase current
RotorRotating magnet that spins inside the statorWire coil between two interlocking iron sections mounted on a shaft
Each lobe is a north or south magnetic pole
Rotor is magnetized only when current is applied through slip rings and brushesSlide32
AlternatorSlide33
Rotor and StatorSlide34
Alternator Components (continued)
Rectifier DiodesAlternator produces alternating currentRectifier diodes changes alternating current to direct current
Field diodes are used to separate field circuit from rectifier circuitVoltage Regulator
Voltage regulator performs two tasks
Regulator excites the field coilRegulator regulates the output voltage of the alternator to a set safe value during chargingSlide35
Alternator Output Test
Output test checks alternators ability to deliver rated output of voltage and currentPerformed if unit is over or under chargingRun unit at high speed
Adjust load to highest current with out dropping voltage below 12 voltsRead ammeter, reading should be with in 10% of the alternators rated output capacity
Always follow the load tester manufactures instructions when testing an alternators outputSlide36
Alternator Removal and Installation
Always disconnect battery firstIdentify positive an negative terminal before hooking up, reversed polarity can destroy rectifier diodesAlternator belt should wrap around pulley a minimum of 100 degrees and be 90 degrees with face of pulley
Check belt tension by consulting the maintenance manualIf charging the battery on the unit, disconnect the positive cable to prevent damage to the alternator or voltage regulatorSlide37
Alternator Installation
Belt to Pulley AlignmentBelt Engagement in PulleySlide38
Starters
Two styles used in transportation refrigeration, conventional and gear reductionConventional starter pinion gear mounted on the motor armatureConventional starter uses solenoid to pull plunger and lever to move pinion gear into mesh with ring gear
Gear reduction starter uses smaller high speed motorGear reduction pinion gear turn at 1/4 to 1/3 motor speed
Gear reduction solenoid acts directly on reduction gear and pinion gear
Overrunning clutch prevent damage to pinion gear once engine startsSlide39
Conventional StarterSlide40
Gear Reduction StarterSlide41
Overrunning ClutchSlide42
Starter Testing
Starter amp draw test ensures starter is in good conditionStarter amp draw test also test condition of batteriesEnsure batteries are in good condition and at a minimum of 50% charge
Use a suitable amp meter on the batteriesDisable the engine from starting during test
Crank engine and watch current drawCranking speed should be normal and current draw should not exceed manufacturers specification
Always follow the manufacturers recommendations for this testSlide43
Safety Switches
Low oil pressure cut out switch protects engine in the event of low or loss of oilInstalled in the oil galley of the engineEngine shuts down if oil pressure drops below 15 psi
High engine coolant temperature switch is normally located in the cylinder head water passagesIf engine coolant temperature rises to a preset point the bimetal switch contacts open circuit causing engine to shut down
Newer style can be an electronic switch that sends signal to the engines microprocessorSlide44
Low Oil Pressure and High Engine Temperature SwitchesSlide45
Safety Switches (continued)
High compressor discharge switch may be mounted in compressor cylinder head, discharge manifold, or line between compressor and condenserHigh compressor switch will shut down engine if a preset discharge pressure is reachedLow compressor oil pressure switch shuts unit down in the event of loss of oil pressure in the compressorSlide46
High Pressure Cut Off SwitchSlide47
Summary
Transport refrigeration equipment uses 12 automotive type storage batteriesBatteries work on principle that when two dissimilar metals in acid bath, and electrical potential is producedEach cell of a battery produces 2.1 volt
12 V batteries use 6 cells connected in seriesAlways follow safety precautions when working around batteries
Batteries may be shipped from manufacturer as wet charged or dry charged Slide48
Summary (continued)
There are three classifications of batteries, conventional, low maintenance, and maintenance freeBatteries are rated by BCI rating, CCA rating, or reserve capacityBatteries should be stored in a clean dry environment between 50⁰F and 60⁰F (10⁰C and 16⁰C)
Batteries can be tested by open circuit test, specific gravity and load testIf a battery has been discharged fast it should be charged fast, if it has been discharged slow it should be charged slowSlide49
Summary (continued)
Jump starting a vehicle is performed when the units battery is low and the unit must run. The battery will require maintenance as soon as possibleThe charging system is responsible for recharging battery once unit is running and providing current for system loads
The rectifier converts alternating current to direct currentThe voltage regulator controls alternator output voltage within a safe limit, as specified by equipment manufactureSlide50
Summary (continued)
An alternator output test confirms how many amps the alternator can produce when fully loaded, in comparison to rated outputStarters for refrigeration units fall into two different categories, conventional starters and gear reduction starters
An overrunning clutch protects the starter from excessive engine rpm by disengaging the pinion gear from the armature of the starterSlide51
Summary (continued)
Starters are tested by measuring the number of amps they draw when starting the engine, in comparison to the starters rated drawSafety switches protect people from any personal injury as well as protect the unit from physical damage caused by running a unit under abnormal conditions