First, the choice of wire Traction wire for tractors, agricultural vehicles can be divided into two kinds of low-voltage lines and high-voltage lines. The choice of low-voltage line is based on temperature rise, while the high-voltage line is based on pressure. Generally in the hot summer, when the temperature around the engine is as high as 70~90°C, the temperature rise of the wire in the environment (the temperature rise caused by the current thermal effect) must not exceed 10°C. The outside of the wire shall be covered with an insulating layer, and the inner part shall be composed of strands of copper wire. The cross-sectional area of ​​the wire shall be of different sizes. The driver may select the wire cross-section according to the size of the passing current. Replacing small-section conductors with large section conductors will cause economical waste: Substituting small-section conductors for large-section conductors will lead to overheating of the conductors and increase of resistance through current passage, which will affect the normal operation of electrical equipment. The requirements for selecting the wire are as follows:
1. The main indicators of high-voltage lines are: good insulation, and their withstand voltage should be above 15,000 volts. The test method is: After immersing the high-voltage wire in warm water for 3 hours, it shall be taken out and tested with AC 15,000 volts for 5 minutes. It shall not be broken down. The thickness of the outer layer of PVC or NBR rubber insulation should not be less than 2 to 4 mm, and the outer layer should be coated with a layer of immersed lacquer.
2. The lead of the battery to the starter motor must not be less than 25 mm2 in cross-section due to the high current to drive the starter. It is generally 40 to 70 mm2.
3. In the lamp line, the cross section of the headlight high beam is 1.5~2.5mm2: the cross section of the headlight near-light conductor is 1~1.5mm2; the cross section of the small lamp, taillight, and turn signal is 0.75~ 1 square millimeter.
4. In the charging circuit, the conductor of the generator armature to the armature of the regulator and the battery of the regulator is 2.5 to 3 mm2: the field from the generator to the magnetic field of the regulator is 0.75 to 1 mm2.
Second, the connection of the wire
The quality of the wire connection will directly affect the service life of the wire and the reliability of the work of each appliance. The correct installation and connection methods are as follows:
1. The single-wire system is used, that is, the power equipment uses only one wire, and the other one is replaced by the airframe. It is often referred to as "over ride."
2. The whole vehicle line generally uses the ammeter as the boundary. The ammeter is connected in series in the charging circuit. The current from the ammeter to the battery is called the current line, and the current from the ammeter to the regulator is called the line after the ammeter.
3. The power switch is the main hub of the line and is connected in series behind the ammeter. One end is connected to the regulator of the power supply (battery and generator), and the other end is connected to the starter switch and other electrical equipment.
4. The electricity-consuming equipment (such as starter motor) with large power consumption is connected to the ammeter before the current does not pass through the ammeter. Some models of electric horns, because of the large power consumption, are mostly connected to the line before the ammeter to avoid high current to burn the ammeter.
5. In addition to starting the motor, all powered devices pass the power switch and are connected in parallel with the power supply on the line behind the ammeter. When the generator is not working or the voltage is lower than the battery, the electricity device is supplied with oil from the battery, the pointer of the current meter swings to the direction of “oneâ€; when the voltage of the generator is higher than the battery, all the electricity equipment is powered by the generator, and The ammeter charges the battery. The ammeter pointer swings to the “+†value direction.
6. The grounding polarity of the battery and the generator and the silicon-rectifier generator must be the same.
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