Re: Using SCR's For Regulating Input Current (fwd)

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Original poster: <sroys@xxxxxxxxxxxxxxxxx>



---------- Forwarded message ----------
Date: Thu, 3 Feb 2005 23:06:57 -0000
From: colin heath <colin.heath4@xxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Using SCR's For Regulating Input Current (fwd)

hi there,
            the scrs are indeed as you say used for pulse width modulation.
the control signal needs to come from some source that controls this. i
would suggest an ic instead of the discreet method as they include zero volt
switching and other useful features. there are many chips about to do this
just google it. i have just aordered some form texas which are the uc3524an
chips but without knowing the current and voltage required to switch the
gates on your devices i wouldnt know if its any good.
cheers
colin heath
----- Original Message -----
From: High Voltage list <hvlist@xxxxxxxxxx>
To: hvlist <hvlist@xxxxxxxxxxxxxxxxx>
Sent: Thursday, February 03, 2005 10:28 PM
Subject: Using SCR's For Regulating Input Current (fwd)


> Original poster: <sroys@xxxxxxxxxxxxxxxxx>
>
>
>
> ---------- Forwarded message ----------
> Date: Mon, 31 Jan 2005 10:57:56 -0600
> From: Carl Litton <Carl_Litton@xxxxxxxxxx>
> To: High Voltage list <hvlist@xxxxxxxxxx>
> Subject: Using SCR's For Regulating Input Current
>
>
> Would someone please explain how the brick-like high current 'power
> module' blocks containing 2 SCR's are used to regulate current?  We are
> interested in pursuing this as an alternative to heavy/bulky variable
> inductors.
>
> We have such a module rated at about 250 Amps continuous and 1200 Volts.
> It has the 3 main terminals: 1 for AC in and 2 (+/-) used to connect the
> SCR's and provide output.  It also has four small terminals, 2 to the
> gates of the SCR's and 2 to the cathodes of the SCR's.
>
> We have been given to understand that such a module may be placed in 1
> leg of the AC input line (along with a potentiometer and such) to
> regulate the input current as a sort of pulse width modulator.  Current
> demand on our input line is about 80-120 Amps and we would like to
> restrict it to a variable 25 to 60 Amps with this type of setup.
>
> We would appreciate a brief description of such a control circuit or a
> link to the explanation and/or a schematic.
>
> Thank you,
>
>
> Carl Litton
>
>
>
>
>