Motor protection circuit breakers act as protection devices for electric motors, monitoring the electrical supply in motor circuits of 50-60Hz. They protect against phase unbalances and losses, which are detrimental to motors, offer protection against current overload, and prevent short circuits.
What are motor protection circuit breakers used for? Motor protection circuit breakers are useful in industrial and building applications such as chillers, compressors, heat pumps and cooling towers, to prevent damages from short circuits or power surges. In the manufacturing industry, circuit breakers interrupt electrical faults below the breaking capacity, which protects machinery and equipment from blowouts.
Types of motor protection circuit breakers Motor protection circuit breakers come in A type or B type classifications, dependent on utilisation and function.
The A type breaker is not explicitly intended for selectivity and does not allow intentional short time delay under short circuit conditions.This means that the system interrupts immediately when current or voltage levels match the breaking capacity.
Type B breakers allow for an intentional and adjustable short time delay under short circuit conditions, which enables the system to continue for a short while with currents exceeding breaking capacity levels.
Description:
DIN rail mounted, mechanically reset protection devices.Transformer short
circuit and overload protectionThe short circuit release is set to 20 x Iu, so even transformers that have high inrush currents have protectionRotary handle for ease of trip indication after a fault has occurredRated operational voltage 690VTrip-fault indicationPhase failure sensitive93 x 45 ...
Description:
Overload protection compensated -5 to +40°CLockable in 'OFF'
positionShort circuit protection, therefore, no back-up fuse protection is required where the prospective fault level is less than the breaking capacity of the unitExpected life cycles 0.1 x 106Maximum switching frequency 40 operations/ hourAmbient temperature (min/max) -25 to +55°C (open) and up ...
Description:
Designed to be used in conjunction with the
Allen Bradley 100-C contactor range to provide type 2 co-ordination without oversizing of the contactor, in rating up to 22kW. The breaker may be customised to suit individual requirements. Trip Class 10Short circuit indicator provides a differentiation between short circuit and overload ...
Description:
Modular Motor Protective Circuit Breakers designed for use
with add-on contactor modules and accessories (see below) which provide isolation, short circuit and thermal protection. The units are DIN-rail mounting and part of the xStart family of control gear products, and a range of connection and wiring accessories are available to ...
