Get the Details About Switchgears
A mechanical switching device is a device used to make or break the flow of a current. When combined with a measuring and control device, they are known as a switchgear. Examples of switchgears include circuit breakers, contactors, isolators, fuse links, relays, and more. In this blog, we will discuss the most common types of switchgears and their function.
A circuit breaker is a mechanical switching device that interrupts the current flow to a connected device when a fault occurs. Circuit breakers are capable of making and breaking contacts during normal operations and can safely interrupt the flow of current in the event of abnormalities. There are many types of circuit breakers, including moulded case circuit breakers (MCCB), vacuum circuit breakers (VCB), SF6 breakers, residual current breakers, miniature circuit breakers, motor protection circuit breakers, and earth leakage circuit breakers (ELCB).
Each type has a unique usage. Miniature and moulded case circuit breakers are used for low voltage circuit protection, vacuum circuit breakers are used for medium voltage circuit protection, and SF6 breakers are used for high voltage circuit protection. Residual current breakers protect against electric shock, motor protection circuit breakers are used for motor protection, and earth leakage circuit breakers protect against earth leakage.
Contactors are mechanical switching devices that are able to make, carry, or break current flow under normal conditions. They are essentially electrically controlled switches that can be used to start or stop electric motors, switch capacitors, and power on/off lights. Contactors are not designed for short circuit current interruption. Low voltage contacts are most commonly the air break type and medium voltage contactors can be of the air, oil, or SF6 types.
Fuse links are self-destructive circuit protection devices that interrupt current flow during short circuits. Fuse links are able to act so quickly that they interrupt a short circuit current before it is able to reach its peak value. Fuse links are available in a broad range of sizes and types.
A disconnector or isolator is a device designed to mechanically open or close a circuit. They do not offer any protective functions. These devices are able to carry rated current during normal working conditions, and are used to switch loads on and off during normal operating conditions. They are also used to isolate the section of electrical installation. It should be noted that disconnectors are not suitable for the switching of electric motors, as the starting current requirements of motors could quickly damage the device.
Electric switches are the most basic and commonly used switchgear. These are used to make, supply, and break electricity to domestic loads. They are available in many forms and are used in domestic, commercial, and industrial functions. Two examples of switches used for industrial applications are limit switches and proximity switches.
The final type of switchgear we will cover in this blog is the relay. Relays are classified into two groups: control relays and protection relays. Control relays are used to open or close a circuit receiving electrical signals. Protection relays are used as trip circuit breakers when a fault is detected.