### Author Topic: Vic design guide  (Read 1245 times)

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##### Vic design guide
« on: June 07, 2016, 10:01:41 am »
Hello

i will share with you one of my vics design understanding...

meyer gave us some numbers to start with so lets get on play and see if the results are plausible...

he said he had in a working cell in resonance when applied 26 to the primary of a transformer

lets say this transformer has a 20 turn primary coil and a step up ration of 30:1 so the secondary must have 600t and should have an output of 780v AC Square pulses

lets say across the primary there is a diode

meyer say the objective with the vic is to pulse it and the secondary will open the circuit together with the diode...

780v/0,02 amps = 39kohm so it would take a coil with this reactance to restrict the amps to 20ma

being the water a short circuit with around 2 ohms resistance or less

when tne secondary reverts the voltage the chokes being in the same core also reverts is voltage

if the chokes also have a 30 : 1 ratio to the primary it totaly chokes of the secondary voltage

the resistance of the coils play a role when the chokes and secondary are on the same core... since it will be the only responsible to restrict any current deriving from a residual voltage in the circuit.. .

the chokes opose the secondary voltage (subtract)

for example if the secondary has 780v and the chokes have 700v there is 80v left

if the coils have 100ohms of resistance total there will be 800ma to flow.. of course 1 amp times 100ohms is 100 watts dissipation

of course the chokes will still have some inductance left even if they are being pulsed.. but arranged in this way it basicaly is arranged as a feedback system since the secondary apply a voltage into it and this induce a voltage on the secondary once again.

15watts should be going for 780v 20ma so the primary will have less than 600ma

the diode across the primary will hold the magnetic field from colapsing all in once maintaining the circuit state

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##### Re: Vic design guide
« Reply #1 on: June 07, 2016, 23:59:47 pm »
Hi Sebosfato.

Transformers are amp restrict tools too.

Are the coils opposing or aiding?

This is a part that make some confusion:

Meyer draws from Thech brief shows the dots in phase, Don's drawings shows positive choke reversed...

Coils outside the transformer core can act as resistance (reactance) too and restrict even more than wire resistance.

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##### Re: Vic design guide
« Reply #2 on: June 08, 2016, 01:25:39 am »
being a restricted amp voltage source is analogous to a high impedance output meaning a amp surge would create such a voltage drop that its output is reduced to zero. .

transformers are impedance transformation devices.. .it translates to the primary the impedance seeing in the secondary side...

To design a transformer you start with current rating than start all the calculation

when i had that problem with my probe power supply i made a nice description how to engineer a transformer for iron cores...

the resistance of the coils is what restrict the amps to obtain regulation.

FOR exx

my load needs 9v 300ma so

i design the secondary to output 10v if the secondary has 3ohm as it will have a 1v drop under load..

the primary voltage drop also must be calculated... for example its feed with 120v and the primary have    to allow 10v x 0,3a so it will absorb this 3w plus the energy that will be dissipated on the primary resistance.. lets say the primary has a thinner wire and longer so its resistance is maybe 100 ohm

i dont really know how to calculate exactly but it goes in approximations

for example you start with the transformer factor for 120vrms to 10vrms already compensating for the secondary resistance... 12x

so the current in the primary is 0,3/12 so 25ma than it will cause a voltage drop of 2,5 volts

so the stepdown should now be a little smaller to get exact 10vrms at the output under no load and to have 9v under load 3,33ohm

the correct transformation factor is than 120-2,5 =117,5v/10v so 11,75 should be the transformation factor

the core size will tell how much power it will handle... the more laminations you add the less turns is needed for a given working voltage input...

to obtain maximum power of the core it must work close to the saturation level such it can use max the flux swing and this can be achieved using known equations like Vrms/4,44/f/A/Bmax  where area is in meters, frequency in hz and Bmax in tesla ... this will give the primary number of turns required for at that voltage to obtain that bmax hz times per second...

http://ludens.cl/Electron/Magnet.html

http://ludens.cl/Electron/trafos/trafos.html

the transformer work by creating a magnetic field on the primary and the secondary when loaded creates a contrary magnetic field a field that cancel the field created by the primary so the power output of a transformer is related also to the coupling and resistance of the coils as the resistance will directly limit the power output by creating a voltage drop.

if we short the circuit of the secondary the current output will lead to a burn...

if we take a 120v input transformer and connect to 5 volt instead we could use a frequency 24 times smaller than the frequency it was rated for.... so it would allow 2,5 hz square wave

« Last Edit: June 08, 2016, 01:48:18 am by sebosfato »

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##### Re: Vic design guide
« Reply #3 on: June 08, 2016, 08:46:03 am »
Hi Sebosfato.

Transformers are amp restrict tools too.

Are the coils opposing or aiding?

This is a part that make some confusion:

Meyer draws from Thech brief shows the dots in phase, Don's drawings shows positive choke reversed...

Coils outside the transformer core can act as resistance (reactance) too and restrict even more than wire resistance.