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Electronic breaker protects groups of loads up to 16A

04 March, 2014

The German circuit protection specialist E-T-A Circuit Breakers has announced an electronic overcurrent protection product that provides selective disconnection of 24V DC loads in automation systems. The 12.5mm-wide 16A ESX10-TB circuit-breaker is claimed to be the first device capable of protecting groups of loads with a total current of up to 16A using a single circuit protector, thus cutting costly downtime and danger to production line personnel.

Usually, in processes powered by 24V DC switch-mode supplies, an overload in one circuit will cause the supply to cut its output to all of the circuits it supplies. When it recovers, it may go into “hiccup” mode, possibly resulting in costly downtime, scrappage and even danger to personnel.

According to E-T-A, traditional protective devices are not the answer. Circuit-breakers with fast operating characteristics can cause nuisance trips during current peaks and can switch on capacitive loads. Conventional MCBs are too slow, and neither delayed operation, nor high-performance circuit-breakers, will respond adequately to over-currents in this situation. The power supply thus switches off completely, bringing all connected loads to a standstill.

The new breakers provide over-current protection for 24V DC control circuits and load currents from 0.5–16A. In the event of overload or a short-circuit, the faulty load is disconnected electronically. It allows selective disconnection of 24V DC switch-mode power supply (SMPS) loads.

E-T-A’s electronic circuit protector can handle groups of loads up to 16A

The breakers provide active current limitation from 1.3–1.8 times their rated current. This allows capacitive loads of up to 75,000µF to be switched on without affecting other loads on the supply. The active current limitation is said to respond much faster to overload or short-circuit conditions than SMPSs. The breaker can shut down a single faulty output, while allowing all other load circuits connected to the same SMPS to continue working as normal. 

After an overload or short-circuit, the load circuit can be re-activated via a remote signal or a manual on/off button. The breakers are available in plug-in or rail-mounting versions. They can be rail-mounted singly or in groups.

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