Double pole electronic Circuit Breaker for Rail Mounting in Process Control
The double pole electronic circuit breaker ESS22-T extends the DC 24 V product range of E-T-A Elektrotechnische Apparate GmbH. It has been designed for rail mounting and allows individual integration into plant concepts of ungrounded DC 24 V power supply networks (IT systems).
Type ESS22-T is an enhancement of the well-proven single pole ESS20 which is already widely used in process control. Typical applications are IT systems in the steel industry, in process control of the chemical industry and in power plant technology. The space-saving device has a width of only 22.5 mm and a height and depth of only 90 mm each. It is therefore ideally suited for use in compact control cabinets. It meets the requirements of the new Machinery Directive 2006/42/EG and the pertinent standard EN 60204-1 “Safety of Machinery, Electrical Equipment of Machines“.
The selective load protection of type ESS22-T provides double pole physical isolation and disconnection exclusively of the faulty path in the event of an overload. This ensures stable DC 24 V control voltage for the other loads (PLC, bus coupler, drive control etc.) even in the event of a fault. Possible downtimes or stoppages will be avoided.
The ESS22-T limits the short circuit current to 1.4 times rated current and disconnects the faulty circuit after approx. 100 ms. Inrush peaks are tolerated. This switching of capacitive loads up to 20,000 μF is possible. In the event of an overload the electronic circuit breaker will trip at 1.1 times rated current after 3 sec. Fixed current rating values from 0.5 A through 10 A to EN 60934 ensure that the integral fail-safe element is adjusted to the cable cross section.
Type ESS22-T can be wired up with max. 2.5 mm² cross section. A multi-coloured LED provides status indication of the connected load circuit. ON and OFF actuation is via a front-side slide switch. In the event of a fault the two physically isolated auxiliary contacts (break and make contact) provide signalling to the control room.
International approvals pending
The double pole electronic circuit breaker ESS22-T will first be approved to EN 60934, standard for circuit breakers for equipment protection. Additionally it will be approved to UL 1077 as a “Supplementary Protector“. This will allow international usage of type ESS22-T in control cabinets in ungrounded DC 24 V circuits.
Caption:
The double pole electronic circuit breaker ESS22-T offers compact DC 24 V protection in a track-mountable design (photo: E-T-A)