Emerald Group Publishing Limited
Copyright © 2000, MCB UP Limited
Keywords: E-T-A, Circuit breakers
E-T-A Circuit Breakers has extended its high-performance thermal circuit breaker family to include a version handling up to 35A. Ideal for applications such as aerospace and motor racing, the latest high-current model maintains the benefits of small size and weight common to the whole family.
The E-T-A 483 Thermal Circuit Breaker for Equipment (CBE) family now includes 12'variants, all in the same compact package (Plate 2). Between them they offer circuit protection from 1A up to 35A. The 483 is a very rugged, temperature-compensated, single-pole CBE with a tease-free operating mechanism ensuring that the contacts open and close with a snap action. It offers a particularly high resistance to physical shock and vibrations, especially the random vibration which can occur in high performance aircraft and racing cars. It also possesses the ability to withstand the effects of a wide temperature variation between -55°C and +125°C.
Plate 2 E-T-A extends the current handling of its high-performance 483 CBE while maintaining the compact size
The threadneck, panel-mounting 483 CBE features a push/pull-on/off manual actuation with an indicator band clearly indicating the tripped/off position. It is certified as an Mtype TO CBE to EN 60934. Depending on the style chosen, it measures just 36.5mm (max.) in length below the panel x 19.5mm wide x 15mm deep (max.), including the terminal connection screws when fully closed. The maximum weight is under 22g excluding hardware.
A high tolerance to sudden current surges is in-built, reducing the risk of nuisance operation, and enabling an optimum match of cable size to circuit breaker rating with weight and cost saving benefits. The electrical short circuit and overcurrent protection capability has ensured its specification on the most advanced aircraft in service today. In racing cars it offers circuit protection for vehicle wiring and components such as fans, fuel pumps, wipers, ignition systems, lights, motors and data logging systems.
The 483 operates at very precise conditions of overcurrent. This prevents the destruction of wiring and components in the protected circuit and minimises the smoke and fire risks that overheating can cause. Such overcurrents may be due to intermittent faults. By resetting the circuit breaker button, the circuit can be immediately re-powered if desired.
The tease-free operating mechanism reduces arcing, minimising power spikes, contact surface damage and contact resistance problems. It features two chamber construction which physically separates the active and compensating bimetals from the switching contacts. The springs, which provide the contact pressure, are thermally isolated from the contact by an insulating barrier.
Details available from E-T-A Circuit Breakers Ltd. Tel: +44 (0) 1296 420336; Fax: +44 (0) 1296 488497.