[Amps] loss of cooling interlock

[John Lyles]

I ran a 4CX1000A at 100 MHz, 1.5 kW CW, with a plugged cooling duct years ago. It started drifting out of tune, and eventually baked some of the nickle plating to a dark tarnish. It was still working, but 
quite far out of tune, i suspect that things were warped inside. 

Another approach is to use a cord or spring, with a temperature sensitive polymer thing attached to the tube. This melts at some temperature and the spring retracts and lets go an interlock contact. 

John 
K5PRO




> 1. The cut-out mechanism would be one of these TO220 sized bimetal switches.  They are available in a variety of trip points.  
> 
> 2. The switch has no electronics inside and should be RF immune.  
> 
> 3. The switch can be set in the chimney near the silicon wall and would not significantly impede airflow.
> 
> 4. The switch has a very low thermal mass and will switch quickly.
> 
> 5. Even with a failed blower, the tube would be dissipating tons of heat and convection would ensure heat-up of the switch.
> 
> 73, Jeff AC?C
> www.ac0c.com