Micro Switches

Actuator

By pressing this part of the micro switch (plunger, hinge lever or roller lever) the switching operation is initiated.

Assembly and Fitting

Snap action switches are only to be mounted by skilled personnel. For screw-mounting a clean and even assembly surface must be provided. Screws must correspond to the established standards, e.g. DIN EN ISO 1580 or DIN EN ISO 4762. It must be ensured, that required clearances and creepages are kept. The actuator in its free position must not be subject to any prestress. Operation can be effected vertically or in angular direction. The angle however should be max. 30° referring to the switch surface and should be determined by testing. The switch housing must not be used as mechanical stopper. Any kind of impact operation on the switch has to be avoided. For a solder connection the usual solder processes in electric industry (e.g. iron and wave soldering) are to be applied. Overheating of the switch during soldering process must be avoided. Force must not be transmitted to the connection pins. When mounting the switch onto a conductive surface it has to be assured that the requirements to prevent touching as well as creepage and clearance distances according to DIN EN61058-1 are met.

Clearance

Shortest distance between two live parts.

Contact Distance

Clearance (approx. 0,3mm) between the opened contacts in normal position. Switches with less than 3,0mm clearance are not approved for direct power line separation and according to European Standards marked "µ". Switches for direct power separation must have a contact distance of more than 3mm.

Contacts and Contact Materials

Our micro switches have silver or gold contacts. These are suitable for most applications and render favorable electrical and thermal features. The application range of silver contacts is usually between 12VAC, 100mA, up to 250V AC, 16A. Gold plated contacts are used at low currents of a few mA and voltages below approx. 20V as well as in sulphurous environment. They are not suitable for higher switching capacities. Since ambient conditions may considerably influence contact safety and electrical load, and thus the lifetime of a switch, we recommend to carry out application-specific tests beforehand.

Contacts and Contact Materials

Creepage

Shortest distance between two live parts along the insulator.

Electrical Lifetime

Number of actuations at rated voltage, rated current and resistive load at 20°C ambient temperature. This is dependent on many aspects, and should be determined by testing for the individual application. It is not possible to refer to any standard diagrams.

Mechanical Lifetime (actuations)

The value indicated on the respective switch shows, when mechanics become unreliable. Please ask for specific test parameters.

Position, Travel and Forces

I End operating Force
Force to be applied to keep the plunger or actuator in the final position.
II Operating Force
Force required to cause con- tact snap-action.
III Differential Force
Difference between operating force and release force.
IV Release Force
Force to be applied to the plunger or the actuator at the moment the contact snaps back from operating position.
1 Normal Position
Position of the switch plunger or the actuator when no force is applied.
2 Operating Position
Position of the plunger or the actuator where the contacts snap.
3 Overtravel Position
Final position of the plunger or the actuator.
4 Release Position
Position of the plunger or the actuator where the contact snaps back from the operating position to its original position.
A Total Travel
Sum of pretravel and over- travel.
B Free Travel
Distance between release posi- tion and normal position.
C Back Travel
Distance between overtravel position and release position.
D Pretravel
Distance between normal posi- tion and operating position.
E Overtravel
Distance the plunger or the actuator travel after actuation. In order to ensure switching safety the minimum value of the respective type must be kept.
F Movement differential
Distance from operating to release position of the plunger or the actuator.

Position, Travel and Forces