Designed for the ultimate in performance in the event of a massive power overload, these circuit breakers disconnect the load from the supply instantly, securely and reliably.

The new WS Series circuit breakers from Mitsubishi Electric have been designed for the ultimate in performance in the event of a massive power overload, disconnecting the load from the supply instantly, securely and reliably. At the core of the circuit breaker's design is the Polymer Ablation type Auto-Puffer. This is moulded in a patented polymer that has been carefully formulated to react with the high temperatures generated locally when shorting occurs to give off significant volumes of an inert gas that prevents the arc from developing further.

In addition, the geometry of the Auto-Puffer is such that the gas is blown at right angles across the arc path at high speed to further assist in extinguishing the spark before it reaches a critical size.

A second innovation sported by the WS Series is the Jet Pressure Trip Mechanism.

This makes further use of the ablation gas which is generated in a confined space, from which it escapes at high speed through a precision designed and positioned nozzle so that its pressure acts on the on the trip mechanism to enhance the speed at which it activates.

The WS series includes an evolutionary advance in Mitsubishi's core circuit breaker technology, the Impulsive Slot type Accelerator (ISTAC).

In this advanced version of ISTAC the current path has been optimised and the electromagnetic drive of the breaker is more powerful.

By increasing the opening speed and improving the arc driving, the rising rate of the arc voltage is increased and thus the peak current, or Ip, is consequentially decreased.

WS Moulded Case Breakers are available in sizes up to 250A with fault levels up to 200 kA.

For an extended working life Mitsubishi has incorporated shuntless current flow technology into the WS circuit breakers, so that double plates hold the conductors rather than wires which would be subject to wear and failure.

Flexibility of the units is ensured because the WS series is equipped with interchangeable relay units, while a number of internal accessories can be added to customise performance characteristics.