Frankly, I don't know what would make them self cleaning either, but
what you describe makes sense. I haven't burnished my contacts for
several years now and they keep working OK even in a windy environment
where there's bound to be a lot of vibration.
Jim Lux wrote:
> At 08:33 AM 12/5/2006, Joe Giacobello wrote:
>> Some time ago, another correspondent on this or a similar list said that
>> the relays in the RCS8 were self-cleaning. Up until that time I had
>> been doing an annual PM by using a burnishing tool on the contacts. Are
>> you guys saying that they are not self-cleaning and do require periodic
> I don't know if the RCS-8V relays are self cleaning; since they're a
> MFJ custom part, there's no data sheet to go look at, although an
> inquiry to Tom, W8JI, might be productive on this point, since he's
> probably seen more of these relays than I've had hot dinners.
> There are other relays that have been mentioned on this list which ARE
> standard parts, and for which the datasheet says what the behavior is.
> To be honest, I'm not sure precisely what makes a contact self
> cleaning, at least by looking at it. There needs to be some lateral
> wiping action, but I suspect it doesn't take much. The overall
> mechanical slop in the mechanism, in combination with the contact
> surface being slightly convex, might be all you need. In a high
> current contactor (a starting relay for an airplane), the cleaning was
> accomplished by setting the contacts at a slight angle, so every time
> it closed, the copper ring that served as the contacts for the
> armature rotated a few degrees. A very clever scheme.
> The contact material also has something to do with it.
> Jim, W6RMK
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