As we know, overcurrent or excess current is a situation where a larger than intended electric current exists. This leads to the excessive generation of heat and the risk of fire or damage to equipment and potential injury for workers. Ensuring you have the proper protection in place can not only protect workers from injury, it can also prevent downtime and maintenance.
Overload protection is a protection against a continuous overcurrent. Overload protection typically operates on an inverse time curve where the tripping time becomes less as the current increases. This means an overload relay isn’t going to trip on momentary or short-term overcurrent events that are normal for the piece of equipment it is protecting. For example some equipment may cause inrush currents as it starts up. However, this inrush current typically lasts only a few seconds and would rarely be an issue. Overload relays are used in a motor circuit to protect motors from damage caused by prolonged periods of overcurrent.
A short circuit occurs when current travels along an unintended path, often where essentially no (or a very low) electrical impedance is encountered. Short circuit protection is protection against excessive currents or current beyond the acceptable current rating of equipment and it operates instantly. As soon as an overcurrent is detected, the device trips and breaks the circuit.
In part 1 of this video topic, we explain how to choose between short-circuit protection or overload protection.
(watch part 2 HERE for a more in depth look)
If you have questions about these or any other products, contact EECO at 800.993.3326