HF Predator mod to parallel

road-runner wrote:

Just buy this step down transformer/voltage regulator

The specs are vague. This device kind of "quacks" like a 1,500 VA continuous, 3,000 peak VA device. I'm concluding this from its price, the fact that it weighs almost exactly half of a good quality 3,000 VA continuous transformer, and the following statements from the Amazon page:

-Maximum capacity is 3000-Watt including the power surge
-Remember to leave at least a 100-percent slack for the voltage converter transformer
-Televisions, heating appliances, laser printers and power tools spike when you turn them on. For these products you need to buy a voltage converter transformer that is at least 3-4 times the items capacity.

I'm curious what technology it uses for the voltage stabilization.

I believe these devices typically use a variac with the wiper controlled using a servomotor setup--basically a variac with a robot to adjust it to maintain an approximately steady output voltage. It's possible instead they use a multitap (auto)transformer and some sort of discrete switching circuit to switch in and out various taps, which is more or less equivalent but quicker acting and arguably more reliable.