[Boatanchors] [Milsurplus] OK Smart People: Capacitive Voltage Divider?

[Rob Atkinson]

I have a question about using a filament transformer to buck 125 v.

It seems to me if you put your 125 v. across the filament winding on
the secondary, then the primary (that normally has 120 v. on it) would
have over 1000 v. sitting there?  Unless I am mistaken I'd take care
when doing this to wrap the primary lugs with 1 kv electrical tape or
cover them in some other way.   Or, am I somehow mistaken about this.

73

Rob
K5UJ


>
>> I'm resurrecting a National NC-100A.
>> Sounds beautiful.  Nice AM, BCB and SWL rig.
>> One problem:  our blasted 125 Volt AC power lines.
>> This rig wants 110 volts and 125 is very tough on it.
>> There is no room to hog-wire in a bucking transformer,
>> so that's out.   Niether can I dedicate a variac to running
>> this receiver.
>> I understand one can use capacitors as an
>> AC voltage divider by placing one in series with
>> a leg of the transformer primary and one across the
>> transformer primary.
>>
>> How can a dummy who can barely do the math
>> needed to number book pages determine what
>> values to use to drop this primary voltage from
>> 125 to 110? Or even if it will work?
>>  Easy!  He askes the dozens of people
>> smarter than him on the mailing lists.
>> Ain't that cool?  ;-)
>>
>> TNX ES 73 DE Dave AB5S
>>
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