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Testing a rectifier

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This video is on the techniques for testing a bridge rectifier.
*** UPDATE ***
"I think you are on the right track in thinking the regulator component is messing up your test.
You see, when I saw your blackboard charging circuit I wondered what was limiting the charge current applied to the battery. In the simplest case a resistor is placed in series with the battery to limit the charge current.
But from what I can see the regulator inside the rectifier unit takes the different approach of shunting excess current away from the battery. If you take a look at the first circuit diagram on this page, you’ll see the bridge rectifier and then to the right the shunt regulator using 3 SCRs - silicon controlled rectifiers - which look like diodes with an extra connection:
(Note this is for a 3 phase system so the bridge uses 6 diodes and the shunt 3 SCRs).
So my guess is that you have a shunt regulator in your unit. It contains an SCR. When you measure from the green to black terminal and get 0.99v, I think you are measuring the voltage drop across the SCR. Ie you are making it behave like a diode.
According to Wikipedia “The device [SCR] behaves as 2 diodes are connected in series with reverse voltage applied.”. That would explain why you are seeing a voltage drop of about 1v, double that of the 0.5v your other diodes are dropping.
I suspect your smaller device is a pure bridge without a built in regulator."
*** UPDATE ***
"I think you are on the right track in thinking the regulator component is messing up your test.
You see, when I saw your blackboard charging circuit I wondered what was limiting the charge current applied to the battery. In the simplest case a resistor is placed in series with the battery to limit the charge current.
But from what I can see the regulator inside the rectifier unit takes the different approach of shunting excess current away from the battery. If you take a look at the first circuit diagram on this page, you’ll see the bridge rectifier and then to the right the shunt regulator using 3 SCRs - silicon controlled rectifiers - which look like diodes with an extra connection:
(Note this is for a 3 phase system so the bridge uses 6 diodes and the shunt 3 SCRs).
So my guess is that you have a shunt regulator in your unit. It contains an SCR. When you measure from the green to black terminal and get 0.99v, I think you are measuring the voltage drop across the SCR. Ie you are making it behave like a diode.
According to Wikipedia “The device [SCR] behaves as 2 diodes are connected in series with reverse voltage applied.”. That would explain why you are seeing a voltage drop of about 1v, double that of the 0.5v your other diodes are dropping.
I suspect your smaller device is a pure bridge without a built in regulator."
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