[ARC5] Solid State 6AL5

[Peter Gottlieb]

If you think it through you can see it. The filter cap is charged to positive peak and then the winding goes to negative peak. Thus, twice 1.414 RMS or 2.8 times RMS. 


Peter

> On Feb 8, 2018, at 5:59 PM, Robert Nickels <ranickel at comcast.net> wrote:
> 
>> On 2/8/2018 2:00 PM, Peter Gottlieb wrote:
>>  looking at the voltages I realized I needed three diodes for each plate!
> 
> An important point to remember (don't ask me why) - solid state rectifiers used in a  full-wave rectifier (full wave with center tap, not a bridge) must have PRV rated at least 2.8 times half of the rms secondary voltage (i.e. the voltage you measure from CT to either end).     That's because the center tap creates essentially two AC sources which are equal in voltage but 180 degrees out of phase with each other.      Diodes in a half-wave or bridge rectifier only need a PRV rating equal to 1.4 times the secondary voltage.
> 
> Especially when converting to solid-state, strongly consider adding inrush current limiting by means of a properly sized NTC thermistor device.  Be nice to those unobtainium transformers.
> 
> 73, Bob W9RAN
> 
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