Classification of circuit breakers – Frame Circuit Breakers (ACB) Frame circuit breaker is also known as universal circuit breaker, all its parts are installed in an insulated metal frame, often open type, can be equipped with a variety of accessories, replacement of contacts and parts is more convenient, mostly used in the power end of the main switch. The overcurrent disconnectors are electromagnetic, electronic and intelligent disconnectors and so on. Circuit breakers have long delay, short delay, instantaneous and ground fault protection, each protection setting value is based on its shell frame level within a certain range of adjustment. The […]

1. What is electricity? Answer:The phenomenon of existence and change of electric charge. Electricity is an important energy source. 2. What is the electric field? Answer: the formation of the field around the charged body, can transfer the interaction between the charged body. 3. What is meant by electric charge? A: The positive or negative charge of an object or a point of mass that constitutes an object. 4. What is meant by potential? A: unit positive charge at a point with the energy, called the point of potential. 5. What is called voltage and its basic unit and common […]

Switchgear refers to a certain programme of primary equipment, secondary equipment assembled into a complete set of power distribution equipment, mainly used for lines, equipment control, protection. Switchgear can be divided into high-voltage switchgear (fixed and trolley) and low-voltage switchgear (fixed and drawer) according to the voltage level of the inlet and outlet lines. The structure of high-voltage switchgear is generally similar, mainly divided into busbar room, circuit breaker room, secondary control room (instrumentation room), feeder room, the room is generally isolated by steel plate. Low-voltage switchgear is mainly classified according to the installation method of components. KYN28A-12 armoured middle-mounted […]

Medium voltage switchgear mechanical tests As an integral step in site acceptance tests, mechanical tests are usually done with the functional tests to test proper signalling and interlocks and save time. In mechanical tests, the commissioning engineer performs mechanical switching of the switching devices, charges the circuit-breaker spring manually with the crank, withdraws the switching device from rack-in to rack-out to test and service positions, and these tests also include testing mechanical interlocks and key pads to make sure they are operating without any trouble. To start these tests, one should prepare a torque wrench, a multi-meter, a test screw […]

Electrical switchgear: how it’s got its name? Many years ago power stations used simple disconnectors, open knife switches, to isolate or de-energize equipment. With the continuous increase in power levels, it became no longer safe to open such disconnectors manually and geared switches were a need which is then combined to be “Switchgear”. Switches didn’t only be geared, but also it was developed to include all the regulating, controlling, metering and switching devices in one unit. Electrical switchgear: what is it? As shown in figure.1 it’s a device in a metal-enclosed structure used to isolate and de-energize electrical equipment. It […]

A Vacuum Circuit Breaker, or VCB for short, is a specialized type of circuit breaker that utilizes a vacuum as the arc quenching medium. This unique design allows it to offer superior arc quenching properties compared to other types of circuit breakers, such as those using oil or SF6 gas. The principle behind the functioning of a VCB involves the production and quick extinguishing of an arc when the contacts of the breaker are opened in the vacuum. As the contacts separate, an arc is formed due to the ionization of metal vapors. However, the arc is rapidly extinguished as […]