Guide: Electrical components are commonly used in gas-fired steam boilers. Electrical components are a very important part of gas-fired boilers. By understanding their role in the circuit, component structure, and working principle, we can grasp their usual operation.

　　Electrical components are commonly used in gas-fired steam boilers. Electrical components are a very important part of gas-fired boilers. By understanding their role in the circuit, component structure, and working principle, we can grasp their usual operation.

　　1. Circuit breaker

　　Low-voltage circuit breakers are also called automatic air switches. They not only function as manual switches, but also can automatically protect electrical appliances against loss of voltage, undervoltage, overload, and short-circuit protection. It can be used to distribute electric energy, start asynchronous motors infrequently, protect power lines and motors, etc., and automatically cut off the circuit when they are seriously overloaded or short-circuited and under-voltage faults.

　　2. Contactor

　　The contactor is an automatic electromagnetic switch that can frequently switch on and off the AC and DC main circuits and the large-capacity control circuit. It closes the contacts through the pull-in under the action of electromagnetic force and the release under the action of the reaction spring. And breaking, so as to control the on-off of the circuit. The main contact in the contact system is a normally open contact, which is used to control the on and off of the main circuit; the auxiliary contact includes two types of normally open and normally closed, which are used to control the circuit and act as an electrical interlock. Other components include reaction springs, buffer springs, contact pressure springs, transmission mechanisms and housings.

　　3. Thermal relay

　　Thermal relays are relays that use the principle of thermal effects generated by current passing through components to act in reverse time.

　　4. Intermediate relay

　　The principle of the intermediate relay is a relay that transforms one input signal into multiple output signals or amplifies the signal (that is, increases the contact capacity). Its essence is a voltage relay, but it has a large number of contacts (up to 8 pairs), a large contact capacity (5-10A) and sensitive action.

　　5. Button

　　The selection should be determined according to the number of contacts required, the place of use and the color. Commonly used LA18, LA19, LA20 series button switches are suitable for AC500V, DC440V, rated current 5A, control power AC300W, DC70W in the control loop.

　　Button color requirements:

　　① The "Stop" and "Emergency Stop" buttons must be red. When the red button is pressed, the equipment must be stopped or powered off.

　　The color of the "Start" button is green.

　　③ The alternate action of "Start" and "Stop" buttons must be black, white or gray. Red and green are not allowed.

　　6. Indicator light

　　The red and green indicator lights have three functions: one is to indicate the operation and stop status of electrical equipment; the other is to monitor whether the power supply of the control circuit is normal; the third is to use a red light to monitor whether the trip circuit is normal, and a green light to monitor whether the closing circuit is normal.