Special technical features of the S850

The S850 Series double NC contact switch has the high quality features of all Schaltbau snap-action switches. To enable both circuits to be switched safely and synchronously throughout their entire working life, our designers had to develop some special solutions.

Compensating the contacts

In the course of the S850’s working life, the contacts may burn up unevenly and the fixed contacts can also exhibit minimal deformation. The design of the switch has to compensate for these changes to prevent it from malfunctioning after only a few months.

The solution for the S850 consists of the sophisticated guidance of the contact bridges in the plunger. This enables height differences between the contacts to be compensated – both individually for each circuit and for both circuits together. The compensating of the contacts is performed by means of three types of freedom to move which the contact bridges have (turning, rocking, and tilting to the side).

Switches that do not have this compensating feature malfunction after only a short time or become unreliable. The errors that arise from this can be very difficult to localise. Switches are often only checked once during troubleshooting. This is not sufficient, because these switching errors often occur only once in 1,000 switching procedures. If the error analysis is then extended to the software, the cost involved can become incalculable.

Contact reliability for varying loads

Switches that actuate power circuits are manufactured with silver contacts that can oxidize. Gold contacts are therefore the better choice for switching small currents and voltages. The self-cleaning mechanism removes impurities and burn-up while switching.

For the S850 our developers implemented the principle of wiping action in such a way that the switch can perform reliably whether the load is high or low. We supply the S850 either with silver contacts or with gold-plated silver contacts.

Positive opening operation

The positive opening feature is, of course, also an integral part of the S850. If the snap mechanism fails because of contact welding, the two positive opening levers push the plunger and thereby the two contact bridges upward: both electric circuits are thus opened.

Accessories for double break and double make contact

Roller levers with or without mounting brackets are available for the S850.

For switching greater loads we recommend the use of magnetic blowout for arc controlling. The permanent magnets are inserted into the recesses provided in the housing.