In accordance with the standards IEC/EN 60204/ VDE0113, all production machines and machine tool must be equipped with a main switch, which disconnects all electrical equipment from all active mains connections during cleaning, maintenance and repair work and during longer downtimes.
Where 2 or more main switches are required, suitable protective interlocking devices must be used. However, we recommend the use of a 4 pole main switch (cam switch).
The main switch must be of one of the following types:
a) Load-break switch which meets IEC/EN 60947-3 and VDE 0660 part 107 for application categories AC23-B or DC-23B.
b) Disconnector with auxillary contact (e.g. A3-10 switching program), which ensures at all times that the switch devices can break the load before the main contacts of the disconnector are opened.
c) The breaking capacity must be break at the same time the current of the largest motor at stall, together with the sum of the currents of all other motors and/or load circuits.
Load-break switches can be used anywhere where compact ON-OFF switches with large contact gaps (isolators) and a high contact pressure, and where a greater short circuit protection is required. They are thus used as main switches in accordance with IEC/EN 60204/VDE 0113 incl. locking device, terminal cover and forced-switching contactors.
Disconnectors according to IEC/EN 60947-3 & VDE 0660 part 107 with switching-positionindicators for 690 V.
3-pole or 4-pole motor switch. In accordance with IEC/EN 60947-3 / VDE 0660 part 107, these LT range switches have a high AC3 & AC23A switching capacity.
Cam switches can be used for practically any purpose, as motor switches, main switches, control switches or instrument switches for example. Alongside the list of switching program s, a practically endless list of special switching programmes can also be used.
SCHRACK cam switches are modular, operate with double disconnection per pole and two contacts per switch cell. Using a variety of models, additional devices and various handles and front frames, they can be used in almost endless combinations. The switches of all types are made up of a locating mechanism and a switch kit. The cams are driven by a stabile, torsionally rigid aluminium shaft. The locating mechanism determines the switching angle and the number of positions. Switches of all sizes and designs can in theory also be designed with 90°-, 60°-, 45°- and 30° switching angles.
Their ideal performance characteristics enable main switches to be used as main switches, emergency stop-, repair- & safety switches.