[Top] [All Lists]

Re: [TowerTalk] More possible RCS8V problems

To: Jim Lux <>
Subject: Re: [TowerTalk] More possible RCS8V problems
From: Joe Giacobello <>
Date: Tue, 05 Dec 2006 13:30:51 -0500
List-post: <>
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.

73, Joe

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
>> cleaning?
> 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


TowerTalk mailing list

<Prev in Thread] Current Thread [Next in Thread>