Circuit protector keeps supplies in balance

A compact electronic circuit protector ensures selective disconnection of 24V DC switch-mode power supply loads while optimally matching the application requirements.

E-T-A Circuit Breakers has extended its range of electronic overcurrent protection products for automation applications with the new ESX10.

Available with seven different current ratings between 1 and 10A, the compact electronic circuit protector ensures selective disconnection of 24V DC switch-mode power supply (SMPS) loads while optimally matching the application requirements.

The new E-T-A ESX10 electronic circuit breaker provides active current limitation to 1.8 or 1.5 times its rated current.

This allows capacitive loads up to 20,000uF or lamp loads to be switched on without affecting other loads on the power supply.

At the same time, this electronic active current limitation responds much faster to overload or short circuit conditions than switch-mode power supplies: the ESX10 will physically isolate a single faulty output, while allowing all other load circuits connected to the same SMPS to continue working as normal.

Status indication is provided by a multicolour LED plus an integral short-circuit proof status output or potential-free signal contact.

In the event of an overload or short circuit, the load circuit may be re-activated electronically via a reset input, or by a manual on/off button.

The on/off button also allows manual disconnection when starting up a system or during maintenance.

The E-T-A ESX10 is just 12.5mm wide and can be plugged directly into an E-T-A Module 17plus power distribution socket which is mountable on a DIN/EN rail.

All electrical connections are then made by means of convenient screwless terminals.

For processes powered by 24V DC switch-mode power supplies without circuits protected by a device such as the ESX10, an overload in a single circuit will cause the power supply to shut down the output to all the circuits it supplies.

On recovery it may go into "hiccup" mode.

Costly downtime, scrap and even danger to personnel may result.

Traditional protection solutions do not provide the answer.

Circuit breakers with fast operating characteristics would be likely to cause nuisance trips during current peaks and switching on of capacitive loads.

On the other hand MCBs are too slow, and neither delayed operation nor high performance circuit breakers will respond adequately in this situation to overcurrents.

The power supply will therefore switch off completely, bringing all connected loads, ie the entire system, to a standstill.

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