Does anybody know which is the nominal H.V. delivered by the BC-453 dynamotor?

Thanks and 73

Tony I0JX

I think the DM-32A was the designated dynamotor for the BC-453. The design
output was 250 volts at .05 amps with 28 volts input. In conversions, the
DM-32 could be used for powering it, as it had 12 volts input and the same
output.

73, Colin K7FM

In article . net,
"COLIN LAMB" wrote:

I think the DM-32A was the designated dynamotor for the BC-453. The design
output was 250 volts at .05 amps with 28 volts input. In conversions, the
DM-32 could be used for powering it, as it had 12 volts input and the same
output.

Colin-

Back in the 50s I used a low frequency ARC-5 receiver (BC-453?) to tune
the 455 KHz IF of a National SW-54, making it a double-conversion
receiver.

The dynamotor had a 28 volt field winding that consisted of two sections
in series. It was common to reconnect them in parallel, and operate off
of 12 volts. However, that produced half the HV output. If there was
more to the mod that gave the full 250 Volts, I never came across it.

Fred
K4DII

On May 17, 4:48 pm, Fred McKenzie wrote:
In article . net,
"COLIN LAMB" wrote:

I think the DM-32A was the designated dynamotor for the BC-453. The design
output was 250 volts at .05 amps with 28 volts input. In conversions, the
DM-32 could be used for powering it, as it had 12 volts input and the same
output.

Colin-

Back in the 50s I used a low frequency ARC-5 receiver (BC-453?) to tune
the 455 KHz IF of a National SW-54, making it a double-conversion
receiver.

The dynamotor had a 28 volt field winding that consisted of two sections
in series. It was common to reconnect them in parallel, and operate off
of 12 volts. However, that produced half the HV output. If there was
more to the mod that gave the full 250 Volts, I never came across it.

Fred
K4DII

Back around 1948, in the UK I recall buying a transformer that had 24
volt heater winding instead of 6.3, along with 5 volts for a rectifier
heater and centre tapped B+ 250-0-250 winding, specifically for war
surplus receiver power supplies. The input was of course 230 volts at
50 cycles. At around age 14 I built a such a power , supply but used
selenium rectifiers instead of a 5 volt tube.

It's just occurred that one could, and people probably have done so
many times already, use any conventional power transformer? Rewiring
the war surplus tube heaters from 24/28 volt to 12 volts, i.e all in
parallel. Then connecting them to the 6.3 + 5 = 11.3 volts windings in
series. An ARC 5, for example, has six 12 volt 0.15 amp tubes; 6 x
0.15 = 0.9 amps, well within the ampacity of both heater windings.
Then using SS diodes for the B+ which even at 250 volts was a maximum
of 60 m/a.

Taking all the wattage into consideration, even at 80% efficiency, the
consumption and heat dissipation would only be 25 watts or less?

A listing on Ebay shows the input at 28VDC and the output as 250VDC.

Dick

On Sat, 12 May 2007 11:01:30 +0200, "Antonio Vernucci"
wrote:

Does anybody know which is the nominal H.V. delivered by the BC-453 dynamotor?

Thanks and 73

Tony I0JX


--
Posted via a free Usenet account from http://www.teranews.com

Thanks for answers

Tony I0JX

On May 12, 7:56 pm, "Antonio Vernucci" wrote:
Thanks for answers

Tony I0JX

But I've also read that the variuos 'command' receivers (BC453, 454
etc,) will work well with much lower B+ voltages.
Which are much kinder on the 60 year old decoupling capacitors etc.
can't remember the value but could it have been as low as 120 volts
DC?
Cos it occurs to me that one could use a 150 volt gas regulator tube
(OD3?) on the output of a power supply to achieve that?

terryS ) writes:
On May 12, 7:56 pm, "Antonio Vernucci" wrote:
Thanks for answers

Tony I0JX

But I've also read that the variuos 'command' receivers (BC453, 454
etc,) will work well with much lower B+ voltages.
Which are much kinder on the 60 year old decoupling capacitors etc.
can't remember the value but could it have been as low as 120 volts
DC?

I can't say that I've seen that applied to Command sets specifically,
but it's not an unknown concept.

IN 1970, there was a two-part article by Fred Brown about updating an
HRO receiver. He replaced the full size tubes with more modern
equivalents, did some other changes, and ran it at a lower voltage than
originally. He gave all kinds of reasons for the lower plate voltage,
and mentioned that the Collins S-line receiver used lower plate voltage.

I think it was that article where he said the only disadvantage was lower
audio output.

Michael VE2BVW


Cos it occurs to me that one could use a 150 volt gas regulator tube
(OD3?) on the output of a power supply to achieve that?

Michael Black wrote:


IN 1970, there was a two-part article by Fred Brown about updating an
HRO receiver. He replaced the full size tubes with more modern
equivalents, did some other changes, and ran it at a lower voltage than
originally. He gave all kinds of reasons for the lower plate voltage,
and mentioned that the Collins S-line receiver used lower plate voltage.

I recall that at the HAMfest at Birmingham (AL) several years ago
(possibly as many as 15) some chap had a BC-348 that he had converted to
solid state. All of the tubes had been replaced by transistors - and it
worked pretty well - at least there in the Jefferson Convention Center.

I've thought about trying the same with one of the arc5 receivers - just
never got around to it. Dave Stinson would probably be one to ask about
such a project - Dave- got your ears on?

best regards...
--
randy guttery

A Tender Tale - a page dedicated to those Ships and Crews
so vital to the United States Silent Service:
http://tendertale.com

Randy or Sherry Guttery ) writes:
Michael Black wrote:


IN 1970, there was a two-part article by Fred Brown about updating an
HRO receiver. He replaced the full size tubes with more modern
equivalents, did some other changes, and ran it at a lower voltage than
originally. He gave all kinds of reasons for the lower plate voltage,
and mentioned that the Collins S-line receiver used lower plate voltage.

I recall that at the HAMfest at Birmingham (AL) several years ago
(possibly as many as 15) some chap had a BC-348 that he had converted to
solid state. All of the tubes had been replaced by transistors - and it
worked pretty well - at least there in the Jefferson Convention Center.

Hank Cross, W1OOP, had an article in Ham Radio magazine in 1969 about
converting one to solid state. It's always interesting how that sort
of conversion went, becuase different people had different philosophy.
Some try to make universal type solid state "tubes". Others build
modules that fit the specific tube socket, but don't tamper with the
existing circuitry. Others, made modules but did do some fiddling
with the existing values.

Hank Cross's philosophy was to basically treat it as a chassis
with coils and capacitors, and hence wasn't stuck with trying to retro
fit solid state devices. It was a mixture of mosfets, bipolar transistors
and ICs. Of course, he also used the opportunity to add some things
he felt missing, like an FM detector (he did a lot of VHF work) and
I think he even made it double conversion.

Michael VE2BVW

I've thought about trying the same with one of the arc5 receivers - just
never got around to it. Dave Stinson would probably be one to ask about
such a project - Dave- got your ears on?

best regards...
--
randy guttery

A Tender Tale - a page dedicated to those Ships and Crews
so vital to the United States Silent Service:
http://tendertale.com