Mirror Contacts for Highly-Reliable Information Relating ...

1 Mirror Contacts for Highly-Reliable Information Relating to safety -Related Control Functions Technical Essay The complete range of Wolfgang Esser contactors, efficient motor- starters and controlled drives for the motor circuit. New simple to install solutions based on clever communication. DIL contactors PKZ motor-protective circuit-breakers MSC motor-starters DS4 softstarters Drives Rapid Link Think future. Switch to green. Summary for fast readers Mirror Contacts for Highly-Reliable Information Relating to safety -related control functions1. - High dependability using newly defined Mirror Contacts - In the last few years, the significance gained additional recognition and terms such as positively-driven of safety -related circuits for personnel significance in safety circuits in the Contacts or the relatively new Mirror protection has become an issue of protection of high-value capital contact .

2 Positively-driven Contacts . which there is a general awareness. investments and guaranteeing a high only partly fulfil the expectations of the The issue is not just subject to level of system availability. The user in safety -related circuits. Clarity is continuous development and review readiness for use of safety circuits exists, achieved by the use of Mirror Contacts , by the German employers liability but there is frequently an element of whose demands are fulfilled by the new insurance association, and for example, uncertainty regarding the properties of DIL M contactors from Moeller. Typical the SUVA (Swiss accident prevention Contacts , the interaction of main and contact properties and the definition authority) in Switzerland, but has also auxiliary Contacts and the standardised will be presented.

3 Literature: [1] IEC / EN 60 204-1 Electrical [6] DIN EN 60947-5-1 (VDE 0660 Part [9] CSA-C No. 14, Industrial equipment of machines, Part 1: 200):2000-08 Low-voltage Control Equipment, Industrial General requirements , non- switchgear and controlgear Part Products . authorized raw translation from 5-1: Control circuit devices and IEC 60 204-1: 2002 / 44/367/CD switching elements; [10] IEC / EN 60 947-1, Low-voltage (Date 6/2002) electromechanical control circuit switchgear and controlgear Part 1: devices (IEC 60947-5-1:1997 + General rules . [2] DIN / IEC 62 061 * Classification A1:1999 + A2:1999), German VDE 0113 Part 50, safety of version EN 60947-5-1:1997 + [11] IEC / EN 60 947-3 and VDE 0660. machinery - Functional safety of A12:1999 + A1:1999 + A2:2000 Part 107 Low-voltage switchgear electrical, electronic and and controlgear Part 3: Switches, programmable control systems for DIN IEC 60947-5-1/A3 Low- disconnectors, switch- machinery , draft June 2003 voltage switchgear and disconnectors and fuse- controlgear Part 5-1: Control combination units.

4 [3] DIN EN ISO 13849-1 (in circuit devices and switching preparation) safety of machinery elements electromechanical [12] IEC / EN 60 947-2 and DIN VDE. - safety -related parts of control control circuit devices 0660 Part 101 Low-voltage systems - Part 1: General principles amendment 3 to IEC 60947-5-1 switchgear and controlgear Part 2: for design intended as a (1997-10) (IEC 17B/1176/CD:2001) Circuit-breakers replacement for: DIN EN 954-1. [7] Wolfgang Esser [4] IEC / EN 60 947-4-1 and DIN VDE Aspects of function safe 0660 Part 102 Low-voltage engineering of contact -related switchgear and controlgear - Part control circuits VER 08+43-787. 4-1: Electromechanical contactors Moeller GmbH, Bonn, 1993. and motor-starters . [8] UL 508, Industrial Control [5] Dirk Meyer Switchgear for Power Equipment.

5 Factor correction systems , VER2100-934 Moeller GmbH, 2003. 1. safety -relevant control function: Control function with a determined degree of reliability, which is intended to retain the safe state of the machine and to prevent the emergence of dangerous situations (IEC / EN 60 204-1, draft 2002 [1], in preparation as IEC 62 061 [2] and DIN EN ISO 13849-1 [3]). 2. contact types and their tasks The varying demands apply primarily for lead to increased contact wear or to the main switching device, as well as welding of the Contacts [5]. Low-voltage switchgear and for the main contact or main circuit. controlgear for industrial applications The main switching devices are applied Table 3 indicates the specific demands is developed, manufactured and tested in main circuits.

6 It is their task during with different examples of switchgear. conform to the relevant sections of the defined exceptional states (overload, For example, the lighter Contacts of IEC / EN 60 947 (Table 2). Depending on short-circuit) to switch the operational contactors are suitable for frequent the type of switchgear and protective load (motor, heating, lighting, etc.) of switching and a long lifespan, whereas devices, different constructive demands the switching and protective devices on the main Contacts from current-zero are placed on the equipment and off, and they must be capable of cut-off circuit-breakers which switch particularly Relating to their task and switching increased currents which less frequently are optimised for higher method of actuation. The varying occur infrequently during defined contact forces to prevent unwanted demands which are placed on the exceptional states (overload, short- dynamic contact bounce with short- 2.)

7 contact element or contact , result from circuit). Various typical utilization circuit currents. A high Icw value is an the application related as well as from categories are defined in the standards important selection criterion with these the construction related demands for correct dimensioning of the main Contacts . On the other hand, highly which are listed in Table 1. Further Contacts and for application specific dynamic main Contacts are required influences result, for example, from the selection of the switchgear sizes ( with current limiting circuit-breakers. type of contact material and the IEC / EN 60 947-4-1 [4]: AC-1, AC-3, DC- medium in which the Contacts switch 5, etc.). The utilization categories in For auxiliary Contacts or auxiliary (air, inert gas and vacuum).

8 Moeller particular, consider the typical inrush switches , which are used to Mirror the selects the materials because of their peak currents associated with differing switching state of the switchgear (main physical and technical suitability with types of equipment, such as the Contacts ) in the auxiliary or control consideration of the environmental extremely high sharp current peaks 2. protection aspects. with capacitors in power factor Rated short-time withstand current: low heating effect with high current conducted over a defined compensation equipment, which can time Mainly Demands placed on Contacts application dependent construction dependent Has an influence on 1 Level of rated current and voltage Selection criteria the construction Has an influence on 2 Voltage type and frequency if applicable Selection criteria the construction Has an influence on 3 Utilization category of the switched load Selection criteria the construction Has an influence on 4 Expected mechanical and electrical lifespan Selection criteria the construction Has an influence on 5 High levels of overload and short-circuit current possible Selection criteria the construction Has an influence on 6 Behaviour during a fault (coordination)

9 Selection criteria the construction Has an influence on 7 Frequency of actuation Selection criteria the construction Repeatability of actuation Selection criteria, consider 8 On machine actuated position switches, actuation cannot be repeated unconditionally after a contact fault, with control circuit devices it is simply a case of actuating the actuator again. with circuit design Dependent on 1 - 8 and on 9 Geometric dimensioning of the Contacts the construction principle Dependent on 1 - 8 and on 10 Number of contact points (interruption points). the construction principle Dependent on 11 Necessary contact motion distances construction principle Dependent on 1 - 8 and on 12 Level of required contact pressure forces the construction principle Table 1: Differing demands placed on Contacts , which are partly dependent on the application, and which are also construction dependent.

10 3. Assignment of the contact types to the general guidelines and product standards and the demands they place on the main and auxiliary Contacts IEC / EN 60 947 Content Demands placed on Demands placed on standards main Contacts auxiliary Contacts Definition of positively-driven Contacts as a relationship between the main and auxiliary Contacts . The definition should Part 1 General rules only be applied to other parts if they have been specifically mentioned in the definition in part 1. No reference to positively- No reference to positively- Part 2 Circuit-breakers driven Contacts to part 1 driven Contacts to part 1. Switch-disconnectors, disconnectors, No reference to positively- No reference to positively- Part 3 switch-disconnector and switch-fuse driven Contacts to part 1 driven Contacts to part 1.