Circuit Breakers for Industrial Applications | Automation.com

Circuit Breakers for Industrial Applications

January 052016
Circuit Breakers for Industrial Applications

By Jeson Pitt, D & F Liquidators

Circuit Breakers for Industrial Applications

Circuit breakers are automatic switches that are specially made to protect electrical circuits from getting damaged. They do that by actively interrupting current flow as soon as they detect an overload, a short circuit or some other faulty condition. A fuse would fall under the same definition save for the fact that it operates only once, and must be replaced upon such an operation. Circuit breakers, on the other hand, only require a manual or automatic resetting once a circuit breaking operation has activated to get them back in operation.

The Difference between Residential and Industrial Circuit Breakers:

Even though both residential circuit breakers and industrial circuit breakers perform the same job, they have their differences when it comes to the capacity of electricity being handled. What’s important to remember is that, regardless of the type of the breaker, the work that it does concerns electricity and therefore this is a sensitive electrical device that should always be handled with care. Understanding the purpose of and differences between circuit breakers puts us at a better place to avoid deadly mistakes.

Now just as the name suggests, residential circuit breakers are specially made to protect the wiring of a home from overheating as a result of the increase in temperature, which is brought about by high current flow within a wire not specified for such. High current flow in the wires at home is normally caused by too many appliances operating from the same wire or output all at once. By tripping, the residential circuit breaker essentially acts as a safety mechanism that is meant to stop any damage or any further damage to the appliances or worse, the whole house.

Industrial circuit breakers on the other hand are designed to handle much larger currents than what you would have in your typical home or residence. Warehouses, factories and large industries will have the industrial circuit breakers integrated within their electrical systems. Structural features, how they are constructed, the way interruption happens and the volt class are normally used to classify industrial circuit breakers.

Common Industrial Circuit Breakers

  • High Volt Industrial Circuit Breakers

High volt industrial circuit breakers are generally designed for 72.5kV and higher volts. These high volt circuit breakers will be found in power transmission circuits and networks. They are usually the solenoid operated circuit breakers that have current sensing protective relays which are operated using current transformers.

At substations these high volt circuit breakers play an important role in protecting the equipment and connective buses from a range of electrical faults that include overloads and earth or ground faults. The high volt circuit breakers are generally classified by their arc extinguishing method. The methods used to extinguish the arc include air blast, bulk oil, minimum oil, a vacuum and the SF6 (sulfur hexafluoride) gas. Most of the newer industrial circuit breakers are now using SF6 gas to extinguish the arc as a response to concerns for the environment and the costs involved in oil spills that can happen with the oil type circuit breakers.

  • Medium Volt Industrial Circuit Breakers

Medium volt circuit breakers work for volts that range from 1 to 72kV. Several of these switches can be put together inside metal enclosures in switchgear like lineups for use indoors or be in individual components that are installed outdoors. Just like the high volt industrial circuit breakers, medium volt circuit breakers are also classified depending on the method that they use to extinguish the arc; i.e. an air circuit breaker, a vacuum circuit switch breaker, the SF6 circuit breaker and so on.  

  • Low Volt Industrial Circuit Breakers

Low volt circuit breakers are often designed for volts that are rated below 1kV. These are very common in domestic and commercial applications as well as in industrial installations. Miniature circuit breakers that have current ratings of less than 100 and molded case circuit breakers with a rating not exceeding 2,500A are some examples of low volt circuit breakers.

  • Industrial Electromagnetic circuit breakers

A magnetic circuit breaker uses an electromagnetic solenoid designed such that its magnetic power increases with the current. As the current along the breaker increases beyond the set threshold, which is essentially the rating for that breaker, the pull by the solenoid becomes strong enough to release a latch that closes the contacts and that circuit gets broken.

  • Industrial Thermal Electromagnetic circuit breakers

Thermal electromagnetic circuit breakers incorporate both electromagnetic circuit-breaking and bimetallic strip trip techniques. The electromagnet responds instantly to large current surges or short circuits while the bimetallic strip reacts to the less extreme yet long lasting over-current conditions. In the thermal magnetic industrial circuit breakers, the thermal part of it offers an inverse time response that is able to allow smaller overloads to last for a while but trip much quicker for the larger over-currents. In the occasion of a really large surge, the magnetic potion breaks the circuit without delay.

  • Industrial SF6 High Volt Circuit Breakers

SF6 industrial circuit breakers use contacts that are surrounded by the sulfur hexafluoride gas which quenches the resulting arc. Industrial SF6 high volt circuit breakers are mostly used in transmission level volts where large currents are involved. They can be incorporated into gas-insulated compact switchgears for more effectiveness. Supplemental heating of these circuit breakers or a calculated de-rating of their capacities may become necessary in cold climates to counter the liquefaction of SF6 gas under low temperatures.

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