90-660 volt goes to 0-277 power supply

[CaEngineer]

Hi Folks!


How I can design a device to give mea voltage between 0 and 277 out of 90-660 volt? I would like to have a pure SIN wave when it passes through.

 

[metalmisers]

Can you be a bit more specific about the project? If i understood correctly you want a adjustable output voltage between 0 to 277 Volts, when the input changes from 90 volts to 660 volts?

 

[CaEngineer]

Can you be a bit more specific about the project? If i understood correctly you want a adjustable output voltage between 0 to 277 Volts, when the input changes from 90 volts to 660 volts?

Yes, I need a pure SIN wave. Lets say if my voltage is less than 277 volt, it is passed through the circuit. otherwise it does not let go through and adjust the voltage.

 

[FvM]

I don't see an easy way to implement the function. Rather unlikely as a series connected element as shown in the schematic, presumning that a variable resistor is a realistic option.

A tapped autotransformer with automatic voltage switching would be a starightforward solution.

 

[CaEngineer]

Let me explain you more. On my electronic board I have a AC/DC converter with the following specifications.

Input voltage max. = 277 volt
Input current max.= 70-80 ma
Freq. = 60 HZ

However, I would like to have the following voltages coming through the board.

120 v

277 v

347 v

600 v

As you can see, I have no problem with 120v or 277v. But for 347 and 600 v I need a self adjuster circuit or I don't know a relay or switch to step down the voltage or clamp it or divide the voltage.

As another solution to my problem, I am also thinking about to have two converters on the board as I could not find any AC/DC converter that works in a range of 90-600. They mostly work in a range of 90-290 v or a range of 300-600 v. I wish I had a converter in a range of 90-600 v instead.

What do you think by explaining the new situation?

 

[FvM]

If the input voltage is sourced from power grid, you have to think also about expectable surges and applicable overvoltage category. The imagined "voltage divider" element must be able to withstand rather high overvoltages.

Provided the AC/DC converter is a regular off-mains switcher, it's input voltage must not necessarily be a pure sine and not even an AC voltage. In so far there are additional options for the "voltage divider" like phase angle control, but it might be effectively cancelled out by the required surge capability.