[ARC5] Receiver AC Power Supplies

[Roy Morgan]

On Dec 12, 2014, at 9:58 PM, Brian <brianclarke01 at optusnet.com.au> wrote:

> ...Be very, very, very careful of marketing 'claims'. A transformer rated at 25 V and 2 A, may not be designed to deliver both at once. The actual deliverable VA depends on the design specifications, not the marketing PR. 

Indeed,

I remember a report about the Radio Shack small filament transformer (maybe the 12.6 volts at 1.2 amps one).  Reportedly, the core in this device went into saturation at a load current much less than the rating . At full current, the output wave form was seriously clipped at both upper and lower peaks.  And, under these conditions, the thing became so hot as to burn the fingers if they were held on the transformer.

Apparently the wire coating and sealing material used in the transformer were good enough to prevent very premature failure of the things.

A friend who is very familiar with late stage tube color TV sets reports that the power transformers in them would run at blistering hot temperatures.  Of course they were used in nearly continuous duty, certainly not ICAS service, and certainly with no fan.

Roy

Roy Morgan
RoyMorgan at alum.mit.edu
K1LKY Since 1958