Reasons for Zero Current of Diesel Generator Set

Today, we will briefly introduce the content about when the current of diesel generator set is zero.

An old customer came to inquire about the reason why the current of the generator set was zero. The control system sent by the customer showed that the frequency did not reach 50HZ and the voltage did not reach 380V, indicating that the speed was low and did not reach 1500 rpm. After communicating with the customer for speed regulation, the current of the generator set was output normally. What are the reasons for the abnormal current of diesel generator set?

There are two situations:

One is that the speed of the power part (diesel engine) that we just said can't reach the rated speed. If it is the power part, it can be solved by increasing the engine speed;

Second, there is a problem with the generator. If it is a problem with the generator, it depends on what generator it is. If it is a brushless generator, it may be degaussing or loose wiring; If it is a brush generator, the carbon brush needs to be replaced or the wiring is loose.

The reasons why the diesel generator does not work are as follows:

1. The magnetic pole of the generator loses magnetism;

2. The excitation circuit element is damaged or the circuit has open circuit, short circuit or grounding;

3. Poor contact between exciter brush and commutator or insufficient pressure of brush holder;

4. The excitation winding wiring is wrong and the polarity is opposite;

5. Poor contact between generator brush and slip ring, or insufficient brush pressure;

6. Open circuit of generator stator winding or rotor winding;

7. The wiring of generator outgoing line is loose or the switch is in poor contact;

8. Fuse is blown, etc.

Processing Method of No-current and Voltage Output of Diesel Generator Set

1. Multimeter voltage range detection

Turn the multimeter knob to the DC voltage 30V position (or use the appropriate position of the general DC voltmeter), connect the red lead to the generator "armature" terminal, and connect the black lead to the housing, so that the engine can run above the medium speed. The standard voltage value of the 12V electrical system should be around 14V, and the standard voltage value of the 24V electrical system should be around 28V.

2. External ammeter detection

When there is no ammeter on the car dashboard, it can be detected with an external DC ammeter. First remove the generator "armature" terminal wire, and then connect the positive pole of the DC ammeter with the range of about 20A to the generator "armature", and the negative pole wire to the above connector. When the engine is running at above medium speed (no other electrical equipment is used), the ammeter has 3A~5A charging indication, indicating that the generator works normally, otherwise the generator will not generate electricity.

3. Lamp test method

When there is no multimeter or DC ammeter, the car lamp can be used as a test lamp to detect. Weld the appropriate length of wire at both ends of the bulb and connect the fish clip at both ends. Before testing, remove the wire of the generator "armature" terminal, and then clamp one end of the test lamp on the generator "armature" terminal, and the other end is grounded. When the engine is running at medium speed, the test lamp brightness indicates that the generator works normally, otherwise the generator will not generate electricity.

4. Change the engine speed to observe the headlight brightness

After starting the engine, turn on the headlight and let the engine speed gradually increase from idle speed to medium speed. If the brightness of the headlight increases with the increase of the speed, it means that the generator works normally. Otherwise, it means that there is no power generation.

5. Multimeter voltage range judgment

Let the battery excite the generator (the wiring method is the same as 2.1), select the multimeter at the DC voltage of 3-5 V (or the appropriate range of the general DC voltmeter), connect the black and red lead to the "grounding" and the generator "armature" terminals respectively, and turn the belt pulley manually. The pointer of the multimeter (or DC voltmeter) should swing, otherwise the generator will not generate electricity.

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