Topband: Vacuum relays powering

[Tom Rauch]

> I would not advise anyone to run Vacuum relays with 
> underrated voltage.The HF-current allowance is a direct 
> function of the contact surface, and that is a direct 
> function of contact pressure and in a "Non-latching"-relay 
> that again is a function of coil current. In short words 
> it may result in reduced current ability and burnt out 
> contacts !! Either use correct Voltage or go for 
> "latching-relays" vacuum style.

I've never thought of this or measured it but doesn't that 
assume the contact surface is compressive and not rigid?

If the contact surface is rigid and in direct contact 
without movable particles or a film that changes resistance 
with pressure, I don't see how increased voltage could 
increase current capacity.

I'm not convinced low voltage is an issue so long as it 
reliably moves the contact. I was experimenting with regular 
relays the other week to see if increased voltage would make 
a relay with a connection problem work, and was not 
successful in finding any change in a go...no go test of 
failed connection through the relay by simply increasing 
voltage. Of course that wasn't testing current capacity at 
all.

It's an interesting thought.

73 Tom