This voltage regular was designed by a new electronics graduate locally 20 years ago and it was not commercially produced (only privately sold) and discontinued. I need to know what kind of design it used and whether it's a buck and boost type.
This is the front and back of the voltage regulator (he used the acronym UPS for Universal Power Stabilizer.. he made it up. It's not an Uninterruptible Power Supply).
[ [ In the following image. The transformer 220V primary wires are connected directly to the output leads (or black outlet). Note the black wire is the neutral, the white at middle is connected to the 110V output outlet at back (I read that in buck and boost type, it is the secondary that is connected to both source and load, but in this case it is the primary that is connected to the load)
[ Here you can see the all secondary leads of the transformer connected to the circuit board.
[ The following is the circuit board. The 833H-1C-C is a general purpose relay. The circuit doesn't have any DSP controller. Here http://www.stabilizer-regulator.com/voltage-stabilizer/static-voltage-regulator-dubai it says a buck/boost type voltage regular has DSP.
Anyone has encountered or familiar what kind of voltage regulation this uses?