The compact contactors C155, C156 and C157 are designed for switching middle and high loads frequently. The switching elements can be replaced individually.

During switch off, an electric arc is ignited between the opening contacts. The current flows on through the ionised air. Permanent magnets drive the ionised air out of the contact zone into the arcing chamber. Here, the electric arc is extended and cooled until it goes out.

For DC voltages of up to 40 volts, a cam switching element with a permanent-magnetic blowout mechanism is to be selected. At voltages of over 40 volts, an electric arc chamber should also be used. At voltages of over 400 volts, the switching element S307 G/N with arcing chamber LK-S307 DC must be used.

The multi-pole cam contactors C155, C156 and C157 can be used in all DC applications up to 1,000 V in which the load does not have to be switched off in both directions:

• Railway technology
• DC drives of machinery

In order to protect the coil of the contactor from excessive heating, a resistor is connected in series with the coil after switch-on.

Optionally, an electronic economy circuit can be chosen. This supplies the required pick-up current for the activation. The current is then regulated down by the electronic economy circuit to the a significantly lower holding current. As a result, the coil becomes less hot and the control power is reduced considerably. The module is attached directly under the contactor.

The switch state of the main contacts can be reported to higher-level control systems and devices through auxiliary contacts.

Break contacts, make contacts or combinations of these are available with the cam-operated switching elements of the S007 series. For safety-related tasks, S800 or S826-series snap-action switches can be chosen: Changeover contacts with double-break contact and mechanical positive opening operation .

The auxiliary switch blocks are installed ex-factory. Quantity and contact type are to be specified during the order.