【Daily Question 20090326】What are the causes of short circuits? What are the harms? Can short circuits be utilized in production?
Thread Content
What is the cause of the short circuit? What are the harms? Can short circuits be utilized in production? Summary: Answer: Reasons for the short circuit: (1) Incorrect wiring ； ⑵Insulation damage ； ⑶Operation error ； ⑷Caused by mechanical damage. Dangers of short circuits: In a short circuit, the current does not flow through the load but only within the power supply. The internal resistance is very low, which results in a high current. This strong current generates significant thermal and mechanical effects, which can damage the power supply or circuit, or even cause a fire. Utilization of short circuits: Welding machines use short circuits to generate a high current, which creates an arc between the welding rod and the workpiece to carry out welding ； When the motor starts, the current is very high; the switch connected in parallel with the ammeter can be turned off to short-circuit the meter, so that the motor’s starting current does not pass through the ammeter, thereby protecting it. The switch should be turned back on after the starting process is complete. This post was last edited by Mobei Yihai on 2009-3-27 08:36.]
Reasons for short circuit (1) Incorrect wiring； (2) Insulation damage ； (3) Operational error ； (4) Caused by mechanical injury. Dangers of short circuits: During a short circuit, the current does not flow through the load but only within the power supply. The internal resistance is very low, which results in a high current. This strong current generates significant thermal and mechanical effects, which can damage the power supply or the circuit, or even cause a fire. Utilization of short circuits: Welding machines use short circuits to generate a high current, which creates an arc between the welding rod and the workpiece to enable welding ； When the motor starts, the current is very high; the switch connected in parallel with the ammeter can be turned off to short-circuit the meter, so that the motor’s starting current does not pass through the ammeter, thereby protecting it. The switch should be turned back on after the starting process is complete.
A short circuit occurs when a high-potential terminal and a low-potential terminal come into direct contact, resulting in a strong current that damages the equipment. Short circuits in household electrical circuits are usually caused by aging wires, which lead to direct contact between the live wire and the neutral wire. Reasons for short circuit (1) Incorrect wiring ； (2) Insulation damage ； (3) Operational error ； (4) Caused by mechanical injury. Dangers of short circuits: During a short circuit, the current does not flow through the load but only within the power supply. The internal resistance is very low, which results in a high current. This strong current generates significant thermal and mechanical effects, which can damage the power supply or the circuit, or even cause a fire. Utilization of short circuits: Welding machines use short circuits to generate a high current, which creates an arc between the welding rod and the workpiece to enable welding ； When the motor starts, the current is very high; the switch connected in parallel with the ammeter can be turned off to short-circuit the meter, so that the motor’s starting current does not pass through the ammeter, thereby protecting it. The switch should be turned back on after the starting process is complete.
Utilization of short circuits: The characteristics of short circuits can be exploited to check whether the instrument signal wires from indoors to outdoors are correct.
The second floor covered everything very thoroughly. I’ve learned that after making the connections, it’s necessary to check them to avoid short circuits.
Strongly agree with the reasons for the short circuit in the following answer: (1) Incorrect wiring； (2) Insulation damage ； (3) Operational error ； (4) Caused by mechanical injury. Dangers of short circuits: During a short circuit, the current does not flow through the load but only within the power supply. The internal resistance is very low, which results in a high current. This strong current generates significant thermal and mechanical effects, which can damage the power supply or the circuit, or even cause a fire. Utilization of short circuits: Welding machines use short circuits to generate a high current, which creates an arc between the welding rod and the workpiece to enable welding ； When the motor starts, the current is very high; the switch connected in parallel with the ammeter can be turned off to short-circuit the meter, so that the motor’s starting current does not pass through the ammeter, thereby protecting it. The switch should be turned back on after the starting process is complete.
Everyone has discussed the hazards of short circuits quite comprehensively. Let’s give an example of using a short circuit. After the stator coils of the generator are repaired, they need to be dried. Since the rated current of the generator’s stator coil is 100A, the stator coil of the generator is connected to the output of the welder; the welder supplies a current not exceeding 100A, and the heating resulting from the short circuit of the generator’s coil is used for its own drying.
It’s for checking connections, I guess… I’ve seen construction teams use a single dry cell and a small light bulb to test wiring; they short-circuit one end and check for continuity at the other end to determine whether the connections are correct. Compared to using a multimeter, this method is more cost-effective, and everyone can have one!
See post discussion: http://bbs.hcbbs.com/viewthread.php?tid=361477&highlight=2008.12.31