10E8PT5.5 Application Field and Working Principle

10E8PT5.5 is a type of electrical specialty fuse used to protect high-voltage electrical circuits. It is designed to provide protection from short circuits and overcurrent in circuits operating at voltages up to 1000 V AC and 2500 V DC. 10E8PT5.5 is suitable for use with medium-voltage AC networks, direct current and single-phase AC networks.

Construction

The 10E8PT5.5 fuse consists of a body of the fuse formed a hollow case and cover allowing the fuse elements (or fusible conductors) to be held in place. A stainless steel arcing chamber is constructed around the fuse element, allowing a cooling area for the melting of the fusible conductor during an overload or short circuit condition. The fuse element is held in place by a plastic or copper frame for physical support.

Heating Element and Fuse Element

A 10E8PT5.5 fuse is equipped with two heaters: a fusible element, which is responsible for the actual protection of the system, and a thermal element, which is responsible for shutting down the fuse in case of an overload. The heating element consists of a nichrome wire wound around a fiberglass core.

The fuse element is a copper wire surrounded by mica fiber, which prevents short circuits by melting into two separate pieces when the temperature rises too much. It also provides protection against arcing and exploding a large amount of energy when the fuse is activated, which could cause fire.

Applications

10E8PT5.5 fuses are commonly used in AC line protection applications, such as circuit protection for electronics, HVAC control systems, building security systems and motor/pump control systems. This type of fuse is also suitable for use with generators, industrial equipment, telecommunications, medical laboratories, and SCADA systems.

Other applications include protection of DC circuits, for which a suitable fuse must be used to limit damage to the power conversion electronics in the event of an overcurrent or short circuit. 10E8PT5.5 fuses are also suitable for other circuits operating at voltages up to 1000V AC and 2500V DC.

Working Principle

When an overcurrent or short circuit condition is detected, the 10E8PT5.5 fuse will trip, effectively isolating the circuit from any further electricity supply. In medium-voltage protection applications, the fuse will react faster in the case of an overload, allowing the circuit to be shut down before any damage is done. In DC applications, the fuse will act as a low-pass filter for current disturbances, providing extra protection for the power conversion electronics.

The fuse element in the 10E8PT5.5 fuse is made of a special mica fiber which melts when the temperature rises too much. This process interrupts the path of the current and the fuse trips. The time taken for the fuse to trip depends on the magnitude of the current: if the current is lower, the fuse will trip faster, whereas a larger current can take longer to trip the fuse.