Switch mode power supply

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Robert
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Switch mode power supply

Post by Robert » Tue Jul 02, 2002 1:31 pm

I have a Tamura switch mode power supply
model OVS-24J 24volts DC 16 amps. Would anyone
have a diagram for this unit and is it
possible to convert it to a 13.8 VDC supply?

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Externet
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Re: Switch mode power supply

Post by Externet » Tue Jul 02, 2002 3:56 pm

Hello Robert.<p>Check if there is a potentiometer or resistor trimmer on the circuit. If so, try to reverse engineer that portion schematic diagram to confirm such trimmer does set the output voltage and check its operating range.
If the range is not enough to come down to 13 V, try changing the reference dividing resistor network to suit your goal.
If not, a way I know of is not pretty, but works, since five years ago:
I disassembled the switching transformer, counted the secondary turns, luckily that is the exterior winding, and rewound a lower ratio of turns with a thicker gauge (to fit) enameled wire.
Then, used a very fine enameled wire with the same original number of turns for the voltage sensor circuitry only.
You may need better rated rectifiers for the new secondary.
The new secondary must not connect to the same original PC board traces as those will be used for the reference winding only.<p>Good luck,
Miguel
- Abolish the deciBel ! -

toejam
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Re: Switch mode power supply

Post by toejam » Tue Jul 02, 2002 4:24 pm

If you only need the rated current output of the supply you are trying to use, there are switching regulator circuts available in texas instruments apps books that will do the job easily.The parts cost would probabaly be less then ten bucks

Robert
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Re: Switch mode power supply

Post by Robert » Sat Jul 06, 2002 1:07 pm

Thanks Externet & toejam for your replies.
Iwill check them out later.<p>Robert

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