How To Select The Equipment Based on Calculated Fault Current?
During fault, the equipment—particularly the circuit breakers, busbars, and enclosures—must interrupt or tolerate that surge without breaking. In case the fault current available surpasses the rating of a breaker, it would explode rather than trip. If your internal busbars of the switchboard are not...
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Star-delta Starter – What Are Its Main Advantages?
Consider a star-delta starter as a more intelligent method of motor starting by gradually bringing a motor up to full power. Rather than suddenly putting the full voltage across the motor from the beginning (which results in tremendous current surges), it initially connects the...
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Soft Starter – How Does It Protect Your Motor?
Consider a soft starter to be a unit that coaxes a motor into operation slowly, rather than dumping full power right from the beginning. When we directly start a motor, it draws an enormous burst of current instantaneously. That instant burst of energy can...
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Variable Speed Drive – How Does It Work Exactly?
Variable Speed Drive is an equipment that regulates how quickly an electric motor rotates by varying the electricity it receives. The power supply operates at a constant 50 Hertz frequency, so generally motors operate at a fixed speed. But let’s consider this — do...
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What are Solid-State Circuit Breakers or SSCB?
Circuit breaker protects electrical systems. When there’s a fault—like a short circuit or overload—it disconnects the supply so equipment doesn’t get damaged. Now traditionally, circuit breakers are mechanical. That means they rely on physical movement—contacts opening, springs releasing, arcs forming and being extinguished. And...
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Residual Voltage Protection — Why Is It Important?
Residual voltage and current protection might sound like something out of an engineering textbook, but once we break it down, it’s actually quite easy to understand — and very important for electrical safety. In this article, we’re going to walk through what these protections...
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What is IDMT Curve and how to calculate it? Explained!
IDMT is an abbreviation for Inverse Definite Minimum Time. Essentially, an IDMT curve informs us how long a protective relay will wait before tripping when it discovers an overcurrent fault. The “Inverse” portion is that the larger the fault current, the quicker the relay...
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Overcurrent Protection in Switchboards – How to Design It?
When we install or design an electrical switchboard, we need to ensure that if anything goes wrong (such as excessive current flowing), the system responds appropriately to safeguard people, equipment, and cables. That’s what overcurrent protection is all about. Overcurrent protection is broadly classified...
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How Utilisation Categories Affect Equipment Selection
From an engineering standpoint, utilisation categories identify the kind of electrical loading and switching operation the device can accommodate. As opposed to presuming that all loads are alike, utilisation categories understand that: • Motor-driven loads produce high starting currents • Loads with resistance do...
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Utilisation Categories (IEC 60947): A Practical Guide for Australian Engineers
Utilisation categories define how demanding a switching task is. They are specified in IEC 60947 and classify loads based on their electrical behaviour during switching. They consider the type of load, how it operates, and the stress placed on contacts. Instead of focusing only...
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