Introduction and maintenance of bus starter

The starter is also called a starter motor. It is installed on the flywheel housing of the bus engine and has the function of starting the engine. The starter is composed of a DC motor, a transmission mechanism and a control device.
The starter transmission mechanism includes a one-way clutch and a shift fork. The one-way clutch has the function of transmitting torque and starting the engine, and also has the function of slipping and disengaging after starting to protect the starter from damage. The purpose of the fork is to move the clutch axially so that the starter pinion and the engine flywheel can be brought into mesh.
The control device is mainly composed of electromagnetic switches and relays. The function of the starter control device is to control the engagement and separation of the starter drive gear and the engine flywheel ring gear, and to control the starter circuit to be turned on or off.
Correct maintenance of the starter
1. Always check the connection status of each part and the tightness of the wires.
2. Eliminate the oxides of the wires and the terminals in time, as well as the dust and oil outside the starter, and clean the armature and driving mechanism with gasoline (or kerosene) and dry them to keep them clean.
3 Check the technical status of the solenoid coil.
4. Check the surface condition of the moving and static contacts of the electromagnetic switch. If they are burnt or have black spots, they should be smoothed with 00 grit sandpaper.
5. Check the spring force of the brush (measured with a spring scale). The pressure of the spring on the brush should be within the range of 0.91.5 kg, otherwise it should be adjusted or replaced.
6. Check whether the surface of the commutator is smooth and clean; whether there is jamming in the carbon brush holder; adjust the height of the brush (not less than 1/2 of the original height); whether the contact between the brush and the commutator is standard, if the commutator is commutated There are mild burns on the surface of the device, which can be polished with 00-grit sandpaper. If the burn is serious and the roundness is more than 0.05 mm, it must be re-polished and rounded, and cleaned with 00 grit sandpaper.
7. Check the clearance between the drive gear and various components. After the starter is used frequently for a period of time, all parts have a certain degree of wear. A clearance of 2.5-5 mm should be maintained between the end face of the drive gear and the end face of the flywheel ring gear. If it does not meet the requirements, it can be adjusted by adding or subtracting shims between the starter flange plane and the engine base to ensure good gear meshing.
8. The technical state of the starter can be determined by the no-load test of the starter. Turn on the power supply when the starter is not under load, measure the idling speed and no-load current of the starter, and compare them with the standard values to judge the starter. Whether there are internal circuit faults and mechanical faults If the measured current is greater than the standard value and the rotational speed is lower than the standard value, check whether the armature shaft is bent, whether the shaft sleeve and the shaft are concentric, and whether the armature winding and the magnetic field winding have inter-turn short-circuit faults ; If the measured speed and current are lower than the specified value, check whether the spring force of the brush is too small, and whether the wire connection point, internal wire and commutator are in poor contact. In addition, there should be no sparks on the commutator during the idling test, and the armature should rotate smoothly and without mechanical scratching. The test time shall not exceed 1min, otherwise the motor may be overheated and damaged.