【Daily Question 20090318】What are the general principles for selecting automatic air switches?

Thank you, boss. I want to know this question too; could that fellow from the sea give some guidance?

Also, what is the condition under which gas is turned on and off? Thank you for the explanation of its working principle

The general selection principles for automatic air switches are as follows: 1. The rated voltage of the automatic air switch should be ≥ the rated voltage of the circuit. 2. The rated current of the automatic air switch must be ≥ the calculated load current of the circuit. 3. The setting current of the thermal trip device = the rated current of the load being controlled. 4. The instantaneous tripping setting current of the electromagnetic trip device shall be ≥ the peak current during normal operation of the load circuit.

Based on intuition: 1. Determine the voltage level (number of phases). 2. Determine the maximum and normal currents. 3. Determine the type of distribution (C.D.) (motors, power supply, etc.). 4. Determine the load class (1, 2, 3) and operating hours (operating schedule). 5. Determine the protection requirements (long delay, short delay, overcurrent, quick break, zero sequence, etc.). With this, it’s basically possible to make a decision. What remains is to use personal connections and experience to specifically find some samples to look at. However, it seems that some companies these days don’t specify models but only give specifications: L 6. It’s important to determine the client’s purchasing habits and financial capabilities (it’s quite practical to do so). I usually ask the client about this first; after all, I have clients of all kinds under my care: lol. This also makes communication with the client easier in the future: P. 7. After deciding on a certain product, the next step is to select a specific model, and at this point it’s crucial to determine the switching capacity of the switch (for power supply, distribution, incoming and outgoing lines, etc., such as XXKA). From my experience, there’s an issue at this stage. . . High-end microcircuit breakers can now be connected to low-voltage feeding cabinets; it used to be very difficult! ~ That’s about it~! ~ Checked out the 10th floor. . During the selection process, attention should also be paid to the number of poles of the circuit breaker: 1P, 2P, 3P, 4P. This post was last edited by ZJYSSF on 2009-3-18 at 19:02.]

The general selection principles for automatic air switches are as follows: 1. The rated voltage of the automatic air switch should be ≥ the rated voltage of the circuit. 2. The rated current of the automatic air switch must be ≥ the calculated load current of the circuit. 3. The setting current of the thermal trip device = the rated current of the load being controlled. 4. The instantaneous tripping setting current of the electromagnetic trip device shall be ≥ the peak current during normal operation of the load circuit. 5. The rated voltage of the under-voltage trip device for automatic air switches = the rated voltage of the circuit

The general selection principles for automatic air switches are as follows: 1. The rated voltage of the automatic air switch should be ≥ the rated voltage of the circuit. 2. The rated current of the automatic air switch must be ≥ the calculated load current of the circuit. 3. The setting current of the thermal trip device = the rated current of the load being controlled. 4. The instantaneous tripping setting current of the electromagnetic trip device shall be ≥ the peak current during normal operation of the load circuit.

The general selection principles for automatic air switches are as follows: 1. The rated voltage of the automatic air switch should be ≥ the rated voltage of the circuit. 2. The rated current of the automatic air switch must be ≥ the calculated load current of the circuit. 3. The setting current of the thermal trip device = the rated current of the load being controlled. 4. The instantaneous tripping setting current of the electromagnetic trip device ≥ the peak voltage when the load circuit is operating normally

The general selection principles for automatic air switches are as follows: 1. The rated voltage of the automatic air switch should be ≥ the rated voltage of the circuit. 2. The rated current of the automatic air switch must be ≥ the calculated load current of the circuit. 3. The setting current of the thermal trip device = the rated current of the load being controlled. 4. The instantaneous tripping setting current of the electromagnetic trip device shall be ≥ the peak current during normal operation of the load circuit. 5. The rated voltage of the under-voltage tripper for automatic air switches = the rated voltage of the circuit.

1\ Series 2. Load selection using the curve 3. Rated current 4. Breaking capacity

:Hehe, there are a few more points to consider: ultimate short-circuit breaking capacity, service short-circuit breaking capacity, and short-term current withstanding capacity.