Re: component electrical specifications?


I would use a 1 Ampere "Microswitch" or sometimes called a lever or roller switch.  Note that a magnetic reed switch is not a "Microswitch".   This rating will only be exceeded under a rare condition where there is a short circuit and the lift gate switch activates at precisely the same moment as the short.  All DCC systems will remove power milliseconds after the short occurs.

If you use a higher rated switch the contact material will be silver or similar metal and constitutes what is called a wet contact.  The reliability of this contact depends on enough current being present to wet or partially melt the contact material on making the contact.   Most of the time you will have little or no current flowing when the contact is made.  A high current contact will fail over time by oxidizing the surfaces.  There are exceptions but in general you want a gold or dry contact and gold contacts are rarely rated for more than 1 Ampere.  Exceptions are switches that are designed to rub off oxidization each time they are made, or combination contacts that are silver with a gold over plating.  Combination contacts will remain dry contacts  if the current is always low.  In a high current situation the gold layer of the combination contact is burnt by the current leaving a silver contact.

There are a lot of engineers out there that do not know this information.  It is rarely taught in school and in my case was learned in the field.

Best Regards,
Ken Harstine

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