Fault Analysis of Generator to Regulator Grounding Line Burnout

Symptoms A Beijing BJ212-type old jeep in the engine when the engine has not started a fire, the generator to the regulator while the ground suddenly caught fire.

The car is used in Liaoyuan Automobile Electric Factory production JF151-type alternator, the output is 14V / 50A, the negative ground. The regulator is made by Hubei Shendi Automobile Motor Co., Ltd. FT61-12V voltage regulator (electromagnetic). I saw from the generator to the adjuster between the ground wire is completely charred, burned copper wire exposed on the outside, it is clear that the wire through a larger current was burned to look like this.

Fault inspection and analysis By checking the generator armature and rectifier, etc., did not find the phenomenon of ground and breakdown, the voltage regulator is also normal, determine the cause of the malfunction is not caused by the generator and the regulator itself. Line smoke fire occurs when starting the car, and start the car only start the opportunity to consume a larger current, then the starter current flows to the generator to the voltage between the voltage regulator on the line it? In order to find out the cause of the fire on the line, a series of inspections were conducted on the starting line of the car. In the inspection found that the engine from the body to the car girder between the wire is not installed, when asked to the car driver, he said a few months ago to repair the engine, repair the car is equipped with a ground wire Between the engine and the girder, repair the engine removed when the pick up line, but finished car start car everything is normal, it has been used, also neglected, did not install this root take the wire.

As we all know, the negative battery car is connected to the car beam with a ground wire, the current current on the car starter, engine, motor, lighting and other electrical equipment are the current through the car beam this big conductor Line) back to the battery negative. The car's starter is bolted to the engine body shell, when the starter motor starting current loop, the engine and the girder in good contact with the current can flow unimpeded back to the battery negative, then there is no burning Before the line fault, and did not install the engine and the girder between the ground line, the starter current loop is how to turn it? It is by the engine claw pad bolt and beam contact, the starter current through the engine claw bolt to the girder and back to the battery negative, it is able to start the engine, but after a period of use, with the claw Loose bolts and mud splashed with water after the vehicle splashed the claw bolt corrosion, the engine and the beam formed between the larger resistance, due to poor contact with the engine and the beam, the starter current can not be successfully conducted, but at this time there is no Install the motor to the ground between the wire, the starter current in the case of the circuit will not flow to the generator to the voltage regulator ground wire. So why the current and then bias the generator to the regulator of this wire it? Because the generator is bolted to the engine and the voltage regulator is bolted to the cab, the cab is bolted to the frame, so the starter current is drawn from the generator housing Generator to the regulator to take the line to the regulator base, and then by the cab to the beam back to the battery negative, constitute a loop. In this circuit through the generator to the governor of the wire diameter is only about 3mm2, so when starting the car it can not afford the starter of high current, so the line will be burned pyrotechnic fire . After the cause of the burning wire fault is confirmed, a standard ground wire is connected between the engine body and the girder, and the charred wire is replaced again. The test run is started and everything is normal.

The failure of the exclusion hope to be able to prompt repair personnel and drivers, repair the car must not ignore the engine body to the girder between the wire. The current automotive electrical lines are mostly single-wire system, the engine body, girders themselves have replaced the role of a wire, so to ensure good contact between them. From the engine to the girder of the ground line is very important, it not only can guarantee the starter's normal start, but also to protect the role of the line.

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