Electrical Encyclopedia: What is the open knife switch, single pole double knife double throw switch, load isolation switch, knife switch, etc.

First, what is the open knife switch

Open knife switches are HD11 series, HD12 series, HD13 series, HS11 series, HS12 series, HS13 series of knife switches, they are all open type knife switches, others are called knife switch or knife switch.

Second, what is a single pole double throw switch

The single-pole double-throw switch consists of a moving end and a non-moving end. The moving end is a so-called "knife". It should be connected to the incoming line of the power supply, that is, the end of the incoming call, which is generally the end connected to the handle of the switch; the other ends It is the two ends of the power output, the so-called fixed ends, which are connected to the powered devices. Its function is to control the power supply to output in two different directions, that is, it can be used to control two devices, or it can control the same device for conversion operation.

Third, what is a double-pole double-throw switch

The double-pole double-throw switch is a type of coaxial switch. It is defined by the number of interfaces, code #P#T, and there are single-pole single-throw (SPST), single-pole double-throw (SPDT), single-pole and six-throw (SP6T).

Fourth, what is the load isolation switch

Load disconnectors are widely used in power distribution systems and automation systems in the construction, power, petrochemical and other industries.

Modular design structure, flexible and diverse combination, glass fiber reinforced unsaturated polyester resin for the outer shell, high dielectric properties, protection and reliable operational safety.

The operating mechanism is a spring energy storage, instantaneous release acceleration mechanism that instantaneously turns on and off the double break point contact structure. Independent of the speed of the operating handle, it greatly improves various electrical and mechanical properties.

A variety of structures and modes of operation, there is a window to directly observe the on/off state of the contacts, and there are cabinets and cabinets outside, with front and side operations, and post-board wiring.

The load isolation switch is beautiful, novel, simple, and small in size. It is an ideal choice for similar products.

5. What is the knife switch?

The knife switch, also known as the knife switch, is generally used for AC and DC low voltage (not more than 500V) circuits that do not need to be cut and closed frequently. The operating current cannot exceed the rated value under the rated voltage. On machine tools, the knife switch is mainly used as a power switch, which is generally not used to turn the motor's operating current on or off. The knife switch is divided into single pole, bipolar and three poles. The commonly used three pole knife switch has a long-term allowable current of 100 A, 200 A, 400 A, 600 A and 1000 A. The current product models are available in HD (single shot) and HS (double throw) series.

Six, the knife gate is the knife

The knife gate is a kind of manual switch of power equipment. The alias knife is generally used for low voltage power, and there are single-phase knife gates and three-phase knife gates.

Depending on the application, there are various specifications, generally labeled with voltage and current, such as 220 volts, 16A, meaning 220 volts, current does not exceed 16 amps. Generally, there are porcelain base, plastic cover and copper parts. The upper part is the inlet port, the lower part is the outlet port, and the middle part is designed with the fuse part.

Seven, how to choose the knife switch

According to the number of poles: the main knife switch can be divided into single pole (1 pole) knife switch, bipolar (2 pole) knife switch, three pole knife switch and four pole knife switch.

According to the model, common ones are: HD single-throwing knife switch, HS double-throwing knife switch, HR type knife-melting switch (also called fuse-type isolating switch).

Common selection problems: 1, arc extinguishing cover: If it is only used for isolated power supply (without load), you can choose the product without arc extinguishing cover, the corresponding model is 0. If it is used to break the load (with load) ), you need to choose the product with arc extinguishing cover, the corresponding model is 1.

2, in front of the board or after the board wiring: Generally speaking, it is commonly used for front panel wiring (default), the corresponding model is 8. The wiring after the board is unconventional, you need to explain when ordering. The corresponding model is 9. Under what circumstances do you need post-board wiring? For example, the upper and lower space of the distribution box is relatively narrow, and it is not easy to connect the copper plate. At this time, it needs to be designed as the rear wiring of the board. There is no substantial difference between the front and the back of the board, but the installation method is different, which is related to your design.

3, front operation or side operation: similar to wiring problems, this is related to your design, and your distribution box (cabinet) installation method. The HD13 and HS13 series, which are commonly used for front operation, are mostly used for switch cabinets for front side operation. The HD12 and HS12 series are side-operated, for front side operation, front maintenance switchgear.

4, with or without rotating handle (BX or B): the main body is the same, the only difference is the handle (different operating modes). The easiest way to judge is to look at what cabinet you use. B stands for ordinary handle, lever type operation, installation size is small, and is mostly used in PLG cabinets. BX stands for rotary handle, rotary operation, and is mostly used in GGD cabinets.

5, rated current: should not be less than the sum of the rated current of each load in the circuit. If you are carrying a motor such as a motor, you also need to consider its peak current.

In general, the motor can be calculated at about 1.25 times the rated current. If the motor is rated at 100A, it is necessary to select a knife switch of at least 125A. In general, it is generally recommended to select a larger size knife switch. If the rating is 160A, you need to choose 250A of the larger size.

6, HD11, HS11 is mostly used in magnetic stations, can not be operated with load, only for isolated power supply. Nowadays, it is commonly used with F type (with cover), which greatly improves safety and prevents misoperation.

Eight, knife switch wiring method

The upper and lower sides are respectively connected to different power systems (such as mains or generators), and the intermediate tool load or the switchboard is sufficient. Do not carry the load switch knife switch, the upper and lower sides and the middle side are strictly prohibited to be reversed, otherwise the middle movable knife will be charged with safety. Remember!