Page 224 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

7 Starting with compressed air

In this method an air tank is attached to the engine. Air is filled in this tank by an air compressor. After this, using
compressed air from the tank, the engine is rotated and started.
Precautions for starting the engine with compressed air
The following precautions should be kept in mind-
• Keep hands completely grease free.
• Do not try to fill more than the prescribed amount of air.
• There should not be any space for air leakage in the air tank.
Safety and Maintenance of Engine Starter
To keep the self-starter working for a long time without any inconvenience, it is important to keep the following
things in mind-
1 Self-starter should never be used for more than 30 seconds at a time.
2 Immediately turn off the starting switch as soon as the engine starts.
3 After 1500 km, open the self-starter inspection band and check the carbon bushes to see if they are burnt,
short or run smoothly in the holder. If there is any defect in it, it should be removed.
4 Check the self-armature commutator for grease or copper filings between its segments. If there is any of these
defects, it should be removed. 5. Oiling should be done in bush bearings.
Precautions for starting the engine
The self-starter should be run on the no-load test for as long as necessary. If it is operated for a longer time, its
coils will generate more force, due to which the armature will be pulled towards that pole and the bearing will
quickly get damaged. To start the engine, it is necessary to take care of some precautions, which are as follows-
1 If both current and speed are low, then it shows that the starter Internal resistance is more inside. This fault
usually occurs on the commutator It is caused due to looseness of fitted carbon brushes.
2 If the current and speed are high, then it is known that there is some kind of load or drag on the armature. This
defect occurs due to worn bearing, crooked armature shaft or excessive tension of carbon bush.

3 If while testing, the speed is high and the current is normal or slightly higher, then it shows that the cracking
motor is fine.
Importance of checking starter circuit for proper functioning.
1 Reliable Engine Start: A properly functioning starter circuit ensures that the engine starts correctly every time
you turn the ignition key. This is critical to the utility and safety of the vehicle.
2 Breakdown Prevention: Regular checking of the starter circuit can help identify and resolve problems before
a breakdown occurs. Due to which the problem can be solved by getting it repaired in time.
3 Safety: A faulty starter circuit can pose a risk, especially if the vehicle fails to start in critical conditions.
4 Battery Health: Checking the battery in the starter circuit that provides power to start the engine helps to
monitor the health of the battery and ensure adequate charging.
5 Vehicle Performance: A faulty starter circuit can affect vehicle performance, causing slow starts or intermittent
issues. Therefore, checking and maintaining the circuit is necessary

6 Electrical system integrity: The starter circuit is part of the vehicle’s broader electrical system. Ensuring its
proper functioning can prevent potential problems with other components.
7 Preventive Maintenance: Performing a starter circuit check helps prevent unexpected failures and increases
the lifespan of starter system components.
8 Troubleshooting: Checking the starter circuit is often one of the first steps. Identifying any problems in this
circuit can help the mechanic identify the root cause of starting problems.

9 Overall Vehicle Reliability: By regularly checking this circuit, drivers can be confident that their vehicle will
start reliably.

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CITS : Automotive - Mechanic Diesel - Lesson 62 - 66