[Boatanchors] motor driven variable capacitors

[Randall Berry]

On 08/05/2014 07:02 AM, David Knepper wrote:
> Has anyone “experimented” with using a low rpm motor (3 RPM) to remotely turn a variable transmitting capacitor?
> 
> I am restoring a 1938 Collins 20K broadcast transmitter that used 833A tubes.
> 
> Originally, this Collins transmitter employed several motors to control a number of variable capacitors and rheostats  from the front panel.  Collins Radio  quit replacing these motors in the 20K because the gears were made of a fiber material rather than steel.  The motors in my 20K are missing, of course, for that reason.
> 
> There are relatively small motors that are used to turn the glass plate in a microwave oven.  These motors seem ideal to use when one gets the mechanics all worked out.
> 

 The only problem with microwave oven rotator motors is that they don't
care which direction the are going. They start up and spin one way, next
time they may start up and spin the opposite. At least mine have been
that way.


> I guess you could say that I have my work cut out for me.  Any ideas?
> 
> Thanks