[Collins] 30S-1 power connection question....

[Dr. Gerald N. Johnson]

On Wed, 2007-08-22 at 17:01 -0500, Phil M. wrote:
> I am currently troubleshooting a 30S-1 that seems to have a short in
> the ac primary circuitry.  The symptom is that the control relay has
> a bright flash and the same fuse in one leg of the 230 volt power blows.
> 
> Now the real question has to do with the difference in the manual
> schematic and the plastic tab on the ac power connections.  The manual
> schematic (page 25/26 in my manual) clearly shows the 230 volt connection
> as having terminals 2 and 3 jumpered and 3 and 4 jumpered.  However,
> the plastic plate that covers the terminal strip is also plainly labeled as
> having only 3 and 4 jumpered with 2 being neutral and 1 and 5 being the
> hot legs.  Which is correct?  The bias supply and pilot lights are working.
> 
> thanks for any advice and help, 73,
> Phil
> W5BVB
The schematic in my 1959 vintage yellow book shows pin 1 hot, pin 2
neutral, 3 jumped to 4 and pin 5 the other hot for 240 volts. Shows pins
1, 2, and 3 jumped for 120 volts neutral and pins 4 and 5 for hot 120
volts.

Pins 3 and 4 when jumpered together for 240 volts make the transformer
primary center tap and so under balanced line voltage conditions should
be at the same voltage as the neutral so a connection to neutral is a
safe option.

-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer