News & Events

Maintenance method of forklift generator failure

Author : HITOP

Update time : 2020-09-04 11:20:19

Forklift generators are divided into DC and AC. Because AC generators are superior to DC generators in many aspects, DC generators have been eliminated. At present, domestic automobiles and internal combustion forklifts all use AC generators. The generators are driven by forklift engines. Their function is to supply power to electrical equipment and charge forklift batteries when the engine is working normally. Forklift generators are generally composed of rotors, stators, rectifiers, front and rear end covers, and transmission heat dissipation devices. The common faults of the generator include: the generator does not generate electricity (not charging), the charging voltage is too high, and the charging voltage is too low. When the engine is running normally, the ammeter always indicates discharging and charging and the indicator light is on, indicating that the power system is malfunctioning and should be overhauled in time. details as follows:

1. The generator does not generate electricity.
Trouble phenomenon: When the engine is running at a medium speed or above, the ammeter shows discharging or charging and the indicator light is on.
cause of issue:
1. The fan belt is too loose, slipping or broken.
2. The charging circuit is open, grounded or short-circuited, that is, the circuit from the generator armature connection to the ignition switch is blocked.
3. The regulator regulating voltage is too low, the magnetizing coil and the resistance are ablated and damaged, the primary and secondary contacts are ablated, dirty, etc.
4. The brush insulation is damaged, the spring elasticity is too weak; the brush is stuck in the frame, and the contact with the collector ring is poor.
5. The diode is broken down, short-circuited or broken; the connection between the diode and the stator winding is loose or broken.
6. The insulation of the generator armature and the magnetic field connection column is damaged or the contact is poor.
7. The insulation of the collector ring is broken down.
8. The stator and rotor windings are open, short-circuited or grounded.
9. The rotor claw pole is loose.
10. The maximum power tube of the crystal voltage regulator is open, thereby cutting off the circuit of the excitation current of the alternator, causing the generator to not generate electricity.

2. The charging current is too large
In the case of sufficient battery power, it can still be charged with a charging current above 10A for a long time. Excessive charging current will cause overcharging of the battery, excessive consumption of electrolyte, overheating of the ignition coil, easy ablation of the distributor contacts, easy burning of the bulb, and overheating of the generator. Fault diagnosis and troubleshooting steps for excessive charging current.
Trouble phenomenon: When the forklift is driving at a low speed, the forklift ammeter shows that it is not charging; when the speed is higher than medium speed or the battery is deficient, the charging current is small.
cause of issue:
1. Poor contact of the charging circuit.
2. The fan drive belt is slipping or too loose.
3. The voltage of the regulator is too low, the contacts are ablated, dirty, and poor contact.
4. Individual diodes are damaged.
5. The slip ring is dirty, and the brush and slip ring are in poor contact.
6. Poor connection, short circuit or open circuit of one phase of stator winding.
Fault diagnosis and repair methods:
1. Check whether the fan drive belt is too loose or slippery, and whether the wire is loose and causes poor contact.
2. Check the engine: remove the armature and magnetic field connection post wires, and connect the two wires of the test lamp to the armature and magnetic field connection posts respectively to make the engine run. If the brightness of the test lamp increases as the speed increases, the generator is in good condition; otherwise, there is a fault inside the generator. Check whether the brushes are excessively worn, whether the slip ring is oily, and whether the brushes are in good contact with the slip ring. Whether the card is issued when moving on the rack, whether the diode is damaged, whether there is an open circuit or short circuit in the stator winding, etc.
3. Check the regulator: first open the regulator cover and block the air gap with an insulator to make the shipper run at a medium speed. If the ammeter indicates high current charging, it means that the regulator voltage is adjusted too low, and the spring tension should be adjusted to Increase the regulation voltage. At the same time, check whether the contacts are oily, ablated, whether the resistance is open, loose connections, poor contact, etc.

3. Unstable charging failure
Trouble phenomenon: When the forklift engine is running steadily above the medium speed, the ammeter pointer will swing, intermittent charging and very unstable.
cause of issue:
1. The fan belt is slipping.
2. The wires of the charging circuit are loosely connected and have poor contact.
3. The collector ring is dirty and has poor contact with the brush.
4. The brush is worn out or the spring pressure is too small.
5. The regulator contact is ablated, oxidized, the contact arm spring is too soft, or the additional resistance is unreliable.
Fault diagnosis and repair methods:
1. Check whether the tightness of the fan drive belt is appropriate, and check the connection between the charging circuit wires section by section.
2. Let the engine rotate at a speed slightly higher than the idling speed, remove the regulator cover for inspection, and use a screwdriver to overlap the first-level contact. Improper adjustment of spring tension or poor operation of additional resistor.
3. If the pointer of the ammeter only swings in the high-speed range, it means that the secondary contacts are ablated, dirty, or poorly contacted, or the air gap is improperly adjusted, which should be eliminated.
4. Check the contact between the brush and the slip ring and the internal connection of the generator.

4 Forklift generator maintenance method
1. Frequently clean the dirt and dust on the exterior of the forklift generator, and keep it clean and well ventilated.
2. Frequently check the fastening of the fasteners related to the generator, and fasten the screws in time.
3. The tension of the transmission belt should be appropriate. Too loose, easy to slip and cause insufficient power generation; too tight, easy to damage the belt and generator bearings.
4. When installing the battery, do not install it wrong, usually install the positive wire first, not the ground wire, otherwise the diode will be easily burned out.
5. When the integrated circuit regulator is used, the ignition switch should be turned off immediately if the engine is not running.
6. Never use the "scrape" method to test whether to generate electricity.
7. When the forklift generator fails to generate electricity, please ask a professional forklift maintenance technician to remove it in time, otherwise the forklift will cause more serious failures.

Previous : Electric forklifts with solid tires are preferred

Next : QUESTIONS TO ASK A FORKLIFT DEALER

Language

Language

Maintenance method of forklift generator failure