Laboratory manual experiment

• 
  To measure the specific gravity of electrolyte.
  
• 
  To measure the open circuit voltage of given battery.
  
• 
  High rate discharge testing.
  

• 
  12 v battery.
  
• 
  Hydrometer.
  
• 
  Centre volt meter rang: 3 volts.
  
• 
  Least count: 0.1 volts.
  
• 
  Conventional voltmeter range: 50 volts
  
• 
  Least count: 0.1 volts.
  
• 
  High rate load discharge tester.
  

• 
  The battery is the heart of the automobile electrical system. The battery serve to store electric energy when there is little or no damage for current acts a secondary source of a electrical when the engine is hot running alternatively to meet full requirement of the load on the system. A wide range of batteries varying from 5 to 200hr. Capacity is necessary to meet the requirement of motor industries.
  
• 
  The import of the battery to the electrical system cannot be over emphasized. You must first determine the condition of the battery when solving any electrical problems. Therefore battery tests almost precede all electrical diagnosis.
  

• 
  The automobile battery contains electrolyte which is the mixture of sulphuric acid & distilled water. The specific gravity of electrolyte of given battery should be measured to know the condition of the charge. The following readings should be kept in mind to decide about condition of battery.
  

• 
  Specific gravity can be measured with the help of the hydrometer. The figure no. 1 shows the construction of the hydrometer.
  

• 
  The hydrometer comprises a glass tube of barrel shape caring a rubber bulb at the top and a rubber tube at its bottom side. This is floating that shown in fig. The upper side of float is marked in a specific manner with the help of this scale we can measure the specific gravity.
  

• 
  Remove the cell stopper.
  
• 
  Squeeze the rubber blub of the hydrometer.
  
• 
  Introduce the tube of hydrometer into the such that it dips into the electrolyte.
  
• 
  Release the rubber bulb i.e. suck electrolyte to in the glass barrel.
  
• 
  Note down reading.
  
• 
  Force out the electrolyte.
  
• 
  Repeat the exercise for each all.
  

FIG.1- HYDROMETER

• 
  Draw In the electrolyte just sufficient to left the float.
  
• 
  The float should not bind or stick to the side walls of the glass barrel.
  
• 
  Don’t tack reading immediately after top up.
  
• 
  While reading the specific gravity the hydrometer should be hold such that level of liquid in barrel should be at eye level as shown in figure.
  

• 
  The open circuit voltage also says the condition of the battery so It is necessary to measure the voltage across whole cell. The voltage for single cell should be obtaining nearly 2.2 volts while for whole.
  
• 
  The cell should be 12 volts of battery is having the six numbers of cells for measuring the voltage following precaution should be kept in mind.
  
• 
  If the battery is dirty, then remove it & clean it making sure that the terminals are clean & tight.
  

• 
  From “(-)” to “(+)” terminal.
  

• 
  Open circuit voltage to the battery 12 v high rate discharge test (H.R.D).
  
• 
  11 volts stator test.
  
• 
  12.5 volts head light test.
  

• 
  The test is performed to across of the battery under given load situation and to determine whether it is dead cell or not in given battery.
  
• 
  The fig. shows the construction of individual cell tester. This is expensive devise given high rate of discharge on each cell separately. This comprise a voltmeter & two prods and resistance is arranged such that when the prods and resistant. Voltmeter reads the voltage of the cell under normal starting motor load the remarkable point of the result of this tests are as following.
  

• 
  There should not be the variant of the voltage wrong reading at different cell. it is more than 0.15v between the two cells they should be replace.
  
• 
  The individual cell volt should be 0.15 for each cell.
  

• 
  The battery should be 3 quarter changed before conditioning the battery the test.
  
• 
  Do not keep the contact of the tester for the long time, otherwise battery will be discharged.
  

1. 
   EXPLAIN HYDROMETER TEST.
   
2. 
   EXPLAIN HIGH RATE DISCHARGE TEST.
   
3. 
   EXPLAIN STATE OF CHARGE TEST.
   
4. 
   EXPLAIN SERVICING OF BATTERY.
   

• 
  To conduct the voltage drop test across primary circuit of ignition system.
  
• 
  Quick testing across secondary circuit of ignition system.
  

• 
  A live test engine with a good battery on a test start. (Fully charged)
  
• 
  Voltmeter
  
• 
  Hand tools
  
• 
  Lead& cables
  

• 
  The function of the ignition system is as following.
  

• 
  To provide the intense spark across sparkplug Point.
  
• 
  To produce the spark at the end of the Compression, it mean at specific time.
  
• 
  To supply of spark in a proper sequence in multi cylinder.
  

• 
  The performance of the ignition system depends upon the resistance provided by the primary circuit of the ignition system.
  

• 
  Contact the voltmeter across the terminal of battery. The voltmeter reads usually about 12 volts. If reading is too low, check the battery.
  

• 
  Contact the voltmeter leads across the primary terminal at the ignition coil. Record the reading in the observation table. After taking all the readings add all the voltage drop taken position in 1, 2 & 3 and compare it with the voltmeter voltage drop at source.
  

• 
  position this figure should match with in a tolerance limit of 10.1 volt draw your conclusion in the observation table.
  

• 
  Run the engine at 800 rpm and use a pair of insulated pliers on each cylinder. Remove each sparkplug wire from the plug & hold it about 3 mm away from a good ground. There should be a sharp regular spark impulse for each firing stroke, if the ignition system is in generally good condition.
  
• 
  Another way of setting the secondary of injection is without running the estimate of primary circuit. It is essential to perform the voltage drop test it is as following.
  

• 
  The primary ignition checks out in valves for voltmeter position as shown in figure.
  

• 
  Turn the ignition switch “on”. The switch will remain on for the entire test series.
  
• 
  During the test the contact points should be closed for the verification contact the voltmeter load to coil output terminal. If the volt meter reads the battery voltage. The distributor points are open. The distributor point must be closed for all voltage drops & so the engine over until the voltage drops to lower readings.
  

• 
  Contact the voltmeter leads to the coil output terminal & ground the other lead. Note down the readings in the observation table. Engine for this remove the high tension cable from the distributor & hold it about 3 mm inch away from good ground at the same time close & open the contact breaker point with the help of screw driver. There should be a sharp regular spark impulse for each firing stroke.
  

1. 
   EXPLAIN THE METHOD OF TESTING IGNITION COIL, DWELL ANGLE AND COIL.
   
2. 
   EXPLAIN THE PRECAUTION TO BE TAKEN FOR TESTING IGNITION COIL.
   

• 
  A live test engine with a good battery on a test stand. (Fully charged)
  
• 
  Timing light.
  
• 
  Dwell meter.
  

• 
  Ignition timing test perform by following steps.
  

• 
  For efficient engine operation correct timing at the spark in relation to the position of the crank during compression.
  
• 
  Stroke of the engine is necessary. Timing mark is given either on one vibration damper or on the engine flywheel. This mark should aim with a pointer or a mark on an adjustment stationary part of the engine at the movement a spark appears at no cylinder spark plug. The Ignition timing can be tested by following connection.
  
• 
  The figure shows the connections of the faming light connect the pickup cable to the number 1 ignition cable is connect the light to its proper power source other one vehicle battery or the other voltage line . Now crank the engine on idle speed every time when spark plug now ares the timing light will also glow. This flashing of light should synchronize with the ignition timing mark on flywheel or damper pulley.