Today in class we learnt about starter motors. We Learnt how a starter motor works and operates and the function of each component in a starter. My understanding of the starter motor is very important in now day cars. As withought a starter your car cant start. Starter motor works through get power from the battery, so it very important to have a battery which is charged. Basically starter motors change electrical energy to mechanical. When we turn the ignition the solenoid recieves current from the battery which makes a magnet pulling the plunger back, this engages the pinion to the fly-wheel. Once plunger gets pulled back it makes a connection so that current can flow from the battery to the starter. Current passes through the brushes to the commutator which spins and transfers current to the windings. The magnetic feild created and the poles repel which turns the armature which the spins flywheel and cranks the engine over.
In practical we went on to some test's on the starter motor to see if was operating correctly and then we disassembled it and identified the componets and did some tests on them and then reassembled it to see if was working correctly.
The first test we did on the starter was a no load test using the bench tester. The voltage reading we got was 13.37 volts which is well over the specification of 11 volts, and a current reading of a 37.4 using the clamp meter which is between the spec of 30-50 amps. We then started to disassemble the starter and did some test's on the components of it. we also did a visual check to see any signs of over heating,burning or any physical damage. There were no signs of any of this and the starter was in good condition. We first did a ground circuit test between each of the commutator segements and the armuture shaft. We got a reading of infinity which meant it is an open circuit and its not grounding to the shaft which is good. We did a continuty test between each commutator segment. We got a reading of 0.6 ohms, this means there is a circuit with no resistance which meant it passed.
We checked the length of the brushes to see if was making good contact with the commutator. All of them were well over the spec mark of 5mm meaning that it was making good contact. After the break we got on to testing the solenoid and testing the pull in windings. We connected the 9 volt power supply to the S and M terminals for no more than five seconds, when we connected it the plunger was getting pulled in and was drawing 10 amps. We then moved on to testing the hold in windings. We connected the 9 volt power supply to the S terminal and the solenoid body, it held the plunger in and drew 7 Amps of current, which is within the spec of 5-8 Amps.
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