Re: MOT w/doubler question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Marco Denicolai by way of Terry Fritz <twftesla-at-uswest-dot-net>" <marco.denicolai-at-tellabs-dot-com>

tesla-at-pupman-dot-com wrote:
> 
> Original poster: "Peter Lawrence by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <Peter.Lawrence-at-Eng.Sun-dot-com>
> 
> I'm trying to make sure I understand how a voltage doubler (like in a
> microwave oven circuit) works
(SNIP)

Hello.

Here it goes again, my old post about the double voltage doubler.

I know, my doubler is a little tricky, but here below is a copy of one
of my old emails about it. Note that I actually measured the
thing with a oscilloscope, so my speculations should be rock-solid. Keep
in mind that each voltage doubler block simply shifts the AC
waveshape up of half of its peak-to-peak value. So a plain 2 VAC (peak
values +/- 2.8V) becomes a pulsed voltage with peak values 0 and
+5.6 V. So, there is a doubling but also a level shift: the average
value is no more zero.

***************************************************************************
I had eventually a chance of performing a real measurement on the
circuit
below. I used a digital scope and applied to the mains 3.5 VAC instead
of 220 VAC. After the measurements, I scaled up the results and these 
I am reporting in the following.

                         | |    
       --------|| ||-----| |----*---------- V-
             * || || *   | |    |
               || ||          -----
   220V        || ||          \   /
               || ||           \ /
               || ||          -----
               || ||            |
       --------|| ||------------*--- GND
                                |
                                |
       --------|| ||------------*
             * || || *          |
               || ||          -----
               || ||          \   /
    220V       || ||           \ /
               || ||          -----
               || ||     | |    |
       --------|| ||-----| |----*----------- V+
                         | |    

Voltage V+ to GND oscillates between 6270 V and 0 (2200 VAC * 2 *
sqrt(2) = 6270 Vpp). 
Voltage between V- and GND oscillates between -6270 V and 0.
If the transformers are in phase, voltage between V+ and V- is almost DC
at 6270 VDC.

  V+ |----|    |----|    |----|
     |    |----|    |----|    |
 GND ------------------------------     V+ - V- = 6.3kV DC
     |----|    |----|    |----|
  V- |    |----|    |----|    |----
     
If the transformers are NOT in phase, the output is a sinusoid at 50 Hz
going from 0
to 6270 Vpp * 2 = 12540 Vpp.

  V+ |----|    |----|    |----|
     |    |----|    |----|    |----
 GND ------------------------------     V+ - V- = 0 to 12.5kV DC pulsed
     |    |----|    |----|    |----
  V- |----|    |----|    |----|

I use the last configuration (transformers NOT in phase, 12.5kV pulsed
output).
***************************************************************************

I hope this helps.

Regards