Diesel generator maintenance training of the diesel engine -p86-p90 starter failure ...

Diesel generator maintenance training diesel engine - p86-p90 starter common faults and repair methods

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Second, starter common faults and maintenance methods


1. Diesel generator starter does not rotate

This kind of failure is generally caused by insufficient battery power or poor line contact.

Internal circuit breakers in the starter, poor internal contact of the electromagnetic switch, and open circuit can also cause such failures.

When checking for such failures, you should first check for easily searchable parts as follows:

Check whether there is sufficient electricity in his electricity. Note: The starting fuse fuse current is generally 30A or 60A.

2 Measure the no-load voltage and the voltage at start-up with the multimeter's DC voltage block. If there is a large difference between the no-load voltage and the starting voltage, it indicates that the battery is deficient or has internal faults: If the difference is small or basically the same, indicating that the battery has sufficient power, the next step should be to check the electromagnetic switch and the DC motor.

7 Use a medium size screwdriver to short-circuit the battery post and switch terminal of the electromagnetic switch, as shown in Figure 2. L18 shows. If the electromagnetic switch is closed and the DC motor is running normally after the short circuit, it means that the fault is outside the solenoid switch. If the electromagnetic switch does not pick up after the short circuit, there may be a disconnection inside the electromagnetic switch or the DC motor.

4 Use a screwdriver to short-circuit the battery terminal bar and magnetic field terminal, as shown in Figure 2-119. If the DC motor can operate normally, there is a fault inside the electromagnetic switch. If the DC motor is still not running and there is no spark in the short circuit, it means that there is a fault in the DC motor. If there is a spark, it means that there is a short circuit in the DC motor. The current motor should be removed and repaired.

2. Diesel generator starter operation is weak

Starter operation is weak, and one cause is that the mountain is in poor contact with the battery, the starting resistance is too large, or the internal contact of the electromagnetic switch is damaged due to poor contact.

The inability to repair the starter is as follows;

1 When this kind of failure phenomenon occurs, the viscosity of the oil (as shown in Fig. 2-91) should be checked first and the amount of electricity stored in it should be checked. If these two items meet the requirements, they should be further examined. Note: The starting resistance of the starter is related to the viscosity of the oil. If the winter oil is not used in cold areas and the sulfuric acid concentration of the electrolyte in the battery is properly increased, this kind of failure phenomenon often occurs.

2 Check that the contact surface between the brush and the controller should be approximately 90%.

2 Check if the commutator has burned, scratched or pitted.

4 Check whether the contact copper plate inside the electromagnetic switch has bad contact.

3. The starter idling sometimes hears metal squeaks

The failure of the starter idling is caused by excessive wear of the starter gear and the flywheel ring gear, resulting in an increase in the distance between the starter gear and the flywheel tooth ridge or the friction clutch slippage. Specific maintenance methods are as follows:

1 In the event of such failure, the first or third start should be performed first. If the fault cannot be eliminated, use a flat-blade screwdriver to adjust the adjusting screw at the left bottom of the electromagnetic switch to make the gear and the gear ring easy to mesh with each other, as shown in Figure 2 -31 shows.

2 If the failure is not eliminated after the above adjustment, the starter should be disassembled and the flywheel ring gear, gears, etc., be inspected.

4. After the start button is released, the starter gear cannot be disengaged from the flywheel tooth map. This failure can be caused by: Anti-sintering of the electromagnetic switch wire and the battery charging wire, improper starter assembly, adjustment or return spring spring break Wait.

When checking such a fault, it is generally necessary to block it with a multimeter and measure it from the start button or the external wiring of the electromagnetic switch. If no fault is found in the measurement, remove the electromagnetic switch, then use the electric iron to open the external contact of the electromagnetic switch and take out the copper plate for inspection. Under normal circumstances, contact with the copper plate should not have excessive burning, if excessive burning phenomenon, use sandpaper after polishing and then assembly. If the fault persists after the above checks, the starter should be disassembled and the drive mechanism checked.

Silicon Rectifier Alternator Composition

The battery charging generator has two kinds of direct current generators and silicon rectifier alternators. At present, the most widely used diesel engine is a silicon rectifier alternator, as shown in Figure 2-120. When the diesel engine is working, the silicon-rectified alternator is charged by the six-phase full-wave rectification of six silicon diodes and used together with the matched charging generator regulator to charge the hundred batteries. The silicon rectification alternator is mainly composed of a pulley, a rotor, a stator, a front cover, a brush device, a rectifier diode panel, a fan, a base, a silicon diode, and a shell.

IV. Common Faults and Maintenance Methods of Silicon Rectifier Alternator for Diesel Generator Sets

1. Silicon rectifier AC generator does not generate or charge current is too small

Silicon rectifying alternators do not generate electricity due to open or short circuit of the excitation coil; short-circuiting of the silicon diode breakdown; incorrect connection of the connection line between the generator magnetic field terminal bar and the regulator or poor line contact. The reason why the charging current is too small is generally that the regulator spring is not correctly adjusted: individual silicon diodes are disconnected or disconnected; the carbon brush is in poor contact with the slip ring.

This type of failure inspection method such as

1 In the event of such failures, maintenance personnel should first check whether the connection between the external terminal of the silicon-rectifier alternator and the terminal of the silicon rectifier regulator is connected incorrectly. If the wiring is correct, check whether the inner package or additional resistance of the regulator is damaged, as shown in Figure 2-122 and Figure 2-123.

When the diesel generating set finds a fault at the end of the inspection, a multimeter is used to measure whether the resistance between the terminals of the generator meets the requirements, as shown in Fig. 2-124. Under normal circumstances, the resistance between the terminals “F” and “A” is between 5-22 ohms. If the measured resistance is greater than 2252, it indicates that the brush is in poor contact with the slip ring or has a broken circuit. Under normal circumstances, the contact surface between the carbon brush and the slip ring should be about 85%, and the spring should have a certain pressure. If there is more oil on the slip ring, apply alcohol to clean it. If the measured resistance is less than 5 ohms, it is generally considered to be inside the excitation coil.