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The power and control circuits of a star-delta starter are discussed in this article with the help of an actual star-delta starter wiring diagram. You can find the instructions to calculate the ratings of contactors for a star-delta starter circuit here: Star-Delta starter design tool. Further operation in detail can be found here: Star-delta starter … Read more
An MCCB or Molded Case Circuit Breaker is a modular device used to protect a piece of low voltage equipment or circuit from overload and short circuits. Apart from overloads and short circuits, specially designed MCCBs can protect against ground faults or residual currents. They can be used for power distribution, motor protection, and as … Read more
A surge protection device (SPD) or simply a surge protector is a device used to ensure protection against transient surges. It is used to protect the household and commercial applications from voltage transients. It is connected in parallel to the load it has to protect. What is a transient surge? A transient surge is a … Read more
Several operating indications can be seen on the front of an ACB or MCCB. Being an electrician or an engineer it is important that one must understand those indication and circuit breaker positions. Each of those indications has some critical information regarding the current state of the circuit breaker. The following are the three most … Read more
What is an instrument transformer? Instrument transformers are current and voltage transformation devices that are used to step down the transmission and distribution line voltages and currents to levels that can safely operate measuring instruments, protection devices and control relays by isolating it from the supply voltages. The above diagram shows the basic usage of … Read more
RCCB stands for Residual current circuit breakers and MCB stands for Miniature circuit breakers. Both of them are basic circuit protection devices found in the distribution boards of every house and commercial lighting power distribution boards. Here are the differences between MCB and RCCB. RCCB – Residual Current Circuit Breakers Residual current circuit breakers are … Read more
Potential transformers (PT) or voltage transformers are instrument transformers used for voltage measurements. They are connected in parallel to the line and operates under the same principle of power transformers. They cannot be used used to supply raw power to the loads. They have an accurate voltage ratio and phase relationship between primary and secondary … Read more
What is a current transformer? A current transformer is a type of instrument, used to measure or sense large alternating currents by scaling it to a smaller, safer and measurable value. It transforms the primary current to a proportional secondary value in terms of magnitude and phase. Current transformers are available in various sizes and … Read more
Induction motors are robust and reliable and are used in all industries across the globe. Various methods are followed to start induction motors, out of which star-delta starters are the most commonly used ones to reduce the starting current. Star-delta starters are cheaper than soft-starters and are widely seen in small-scale industries. Typically, star-delta starters … Read more
What is switchgear? Any mechanical switching devices used to make or break the current flow and their combination with measuring and control devices are known as switchgear. This includes circuit breakers, contactors, isolators, fuses, relays etc. This articles intents to describe the different switchgear in short and their switching phenomena. Circuit breaker A circuit breaker, … Read more
