© Siemens AG 2010 BETA Protecting Miniature Circuit Breakers (MCBs) Additional components Overview This mounting concept enables all additional 5ST3 components to be combined with Siemens miniature circuit breakers as well as with 5SU1 RCBOs. Auxiliary releases Auxiliary contacts Undervoltage releases are integrated e. g. in an EMERGENCY- STOP loop, thus ensuring that the miniature circuit breaker trips in the event of an emergency, which in turn ensures disconnec- tion of the control circuit according to EN 60204. In the event that the voltage is interrupted or too low, it also trips, i. e. prevents the miniature circuit breaker from switching on.
The auxiliary switch (AS) signals the contact position of the min- iature circuit breaker regardless of whether the miniature circuit breaker was tripped by hand or by a fault. An additional version for the switching of small currents and small voltages for the con- trol of programmable control systems (PLCs) according to EN 61131-2 is available. The version "auxiliary switch with test button" enables the testing of auxiliary contacts without the need to switch the miniature circuit breaker. Shunt trips are used for the remote tripping of miniature circuit breakers.
Remote-controlled mechanisms are used for the re- mote switching (ON/OFF) of miniature circuit breakers and the remote switching (ON) of RC units. The fault signal contact (FC) signals the automatic tripping of the miniature circuit breaker in the event of a fault, e. g. due to an overload or a short circuit. The contact position does not change when the miniature circuit breaker is tripped by hand. Remote control Remote-controlled mechanisms also enable local manual switching. A blocking function permits maintenance work. In the event that a miniature circuit breaker or RC unit is tripped, an ac- knowledgment must be carried out prior to switching back on.
The remote-controlled mechanism has an operating mode se- lector switch with the functions: "Locked", "Manual" and "Remote Switching". The mechanism can be mechanically latched and locked, which serves to protect personnel during maintenance work. Test and reset button The version "fault signal contact with test and reset button" en- ables the testing of auxiliary contacts without the need to switch the miniature circuit breaker. With this version, if the miniature cir- cuit breaker is automatically tripped in the event of a fault, this also automatically trips the RESET button integrated in the han- dle of the fault signal contact.
After the miniature circuit breaker has been tripped, the reset button can be manually acknowl- edged, which deletes the pending fault signal. RC units are combined with miniature circuit breakers of A, B, C and D characteristics. They then form a combination of RCCB and MCB for personnel, fire and line protection. The combina- tions can be individually assembled to suit the requirement. For information on RC units, please refer to the section "Residual current protective devices". RC units Benefits Universal mountability of all additional components The 5SY and 5SP miniature circuit breakers are ideal for the quick and easy mounting of auxiliary switches and fault signal contacts.
Captive metal brackets on additional components ensure the quick and easy mounting of devices on the miniature circuit breakers without the need for tools. Fault signal contacts with test and reset button enable the sim- ple testing of auxiliary circuits and, in the event of a fault, ac- knowledgement of the fault over the reset button, without the need to switch the miniature circuit breakers. Auxiliary switches for small outputs enable their use with PLCs. Bus systems, such as instabus KNX, AS-Interface bus or PROFIBUS, are integrated in the communication over binary inputs and actuators.
Auxiliary switches (AS) Huge range of applications, thanks to additional versions for the switching of small currents and voltages for the control of programmable control systems (PLCs) according to EN 61131-2. 19 Remote-controlled mechanisms (RC) The remote-controlled mechanism has an operating mode se- lector switch with the functions: "Locked", "Manual" and "Re- mote switching". The mechanism can be mechanically latched and locked, which serves to protect personnel during maintenance work. The auxiliary switches with test button enable easy testing of the control circuits by hand during operation of the complete system without the need to switch the miniature circuit breaker.
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