>
>
>> >No, it has air insulation.
>>
>> The coil-form has air insulation? Did you mean to say ceramic insulation?
>
>Air.
>
How?
>> > >The Oren Elliot Products roller was never used at Ameritron.
>>
>> Where did the Delrin roller inductor come from that reportedly melted down
>> twice in the ARRL lab? thanks > cheers, Tom
>
>Don't know. Ameritron never used the Oren Elliot Products roller.
>
>But I can tell you this, the Q difference between ceramic and
>Delron when only the roller material is changed is minimal. The Q
>of the OEP roller measures about 110 at 3 MHz, the same size
>ceramic core inductor measures 132 both at full inductance.
>
>The actual problem is the wire gauge and resistivity, and the fact
>there is little air circulated across the roller winding, which heats
>primarily from I^2 R losses. As little as 50 watts of heat can ruin an
>OEP roller. Replace it with a ceramic core roller, and the same
>dissipation rises to over 125 watts.
How do you measure disipation in the inductor?
>
>WA1OXT is using two ceramic form rollers in a tuner designed by
>you,
I did not design the balanced L network tuner in Feb.1990 QST. . It was
from Bell Labs research in the 1930s.
> and it has severe heating problems on 160 meters.
Extraordinary. L networks have the lowest Q possible.
>Fortunately ceramic melts at very high temperature.
>
>To cure the problem, he needs to switch to a large gauge
>conductor in the rollers.
>
most people that have built the balanced L Tuner use 12ga variable
inductors.
later, Tom.
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|