cheap solution on AC power regulator

[mikeye04]

Hello everyone,

The unregulated output AC power is from 22VAC to 30VAC, 2.5A max, but the input voltage range of the load is 22VAC~28VAC, load may demage when the power is over 28VAC.

Also, there is a motor inside the load and the motor is remote controlled, when it works, the un-regulated output voltage may drop to 28VAC, but it will go back to 30VAC when the motor stops.

Is there any way I can control the output voltage always safe---that means, when it's 30VAC, I can reduce it to 28VAC. When it's already 22VAC, don't do anything.

Thanks

Mike

 

[itsmoked]

A crummy way would be to provide enough load to always keep the output below 28V perhaps a resistor. (Horrible waste of energy.)

Or replace the transformer with one that has better regulation.

Or add an appropriate autotransformer to shave off the 2V without a lot of power loss.

Or buy the correct supply.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[mikeye04]

autotransformer to shave off the 2V without a lot of power loss is good.

would you pls explain it in detail?

 

[itsmoked]

http://en.wikipedia.org/wiki/Autotransformer

Note that a normal transformer has to pass all the energy thru a magnetic structure. This makes a standard (fully isolated) transformer a certain size. An auto transformer provides no isolation what-so-ever but this results in only a fraction of the power needing to pass thru a magnetic structure. This allows them to be dramatically smaller than their counterparts. Since you only need a 2V adjustment no isolation is probably needed.

Keith Cress
kcress -

http://www.flaminsystems.com