Design Tool
- 1: Switch Basics.
- 1.1: General.
- 1.2: Positions - forces - movements.
- 1.3: Actuator - movement - diagram.
- 1.4: Actuating / Contact force - movement - diagram.
- 1.5: Switch Technology.
- 1.6: Electrical Ratings.
- 1.7: Approvals.
- 1.8: Switch Life.
- 1.9: Application Technology.
- 1.10: Contact.
- 1.11: Switch Actuation.
- 1.12: Environmental Protection.
- 1.13: Recommendations.
- 2: Typical Applications.
Check Availability of our Stock ProductsContact
Contact Materials
Silver and silver alloys are the primary contact materials used in Saia-switches. The ratings tables shown refer to switches with silver/silver alloy contacts. Gold contacts should be specified when switches are to be used in low voltage control or logic circuits, especially when long periods of inactivity are expected or when atmospheres with a high sulphur content may be encountered. Gold contacts are generally available in two forms; gold plated silver alloy contacts, which can also be used at higher currents or gold alloy cross-point contacts, which are only suitable for switching low currents.
Gold-plated contacts
Gold-plated contacts (4 μm) are used for low currents of a few mA and voltages below about 20 V (for DC and AC) and for sulphurous atmospheres. They are unsuitable for higher breaking capacities.
Gold
Gold flash, a thinner deposit, is applied to certain switch terminals to ensure good solderability even after prolonged storage.
How to determine the contact material for SAIA XG/XC-series only
The selection of the appropriate contact material will depend on a number of factors:
- current and voltage
- resistive or inductive load
- inrush current peak
- frequency of switching operations
- atmospheric conditioons
- required switching reliability
Pure silver contacts (standard)
Saia Snap-Action Switches are normally equipped with pure silver contacts (Ag999). These are suitable for most applications and have satis-factory electrical and thermal properties.
Silver-cadmium oxide (AgCdO 90/10)
contacts should be used where high inrush current peaks (30 A or more) are switched on as they tend to weld less at high current loads. They can resist peaks of 80 A or more for several ms provided that they are used with a Saia Snap-Action Switch with high operating and contact force (80 cN in the free position and total-travel position).
At high breaking capacities, switches fitted with such contacts have about 50% longer life expectancy than those fitted with pure silver contacts. Normally, silver-cadmium oxide contacts are not suitable for voltages under 50 V.
Please ask Saia if you would like an assessment for your specitic application.
Contact Resistance
The contact resistance is the electrical resistance measured at the terminals of the switch when the contacts are closed. The resistance specifications refer to unwired switches in new condition.