Thats not technically a variac. It's a multi tap transformer, so it has pre set "speeds" that you can choose from, assuming thats what the switch is for on the front.
It looks like it's wired to plug into power source and the fan plugs into it. I don't see where the thermostat / temperature probe would go though. Need more information.
The image shown with the transformer and pcb looks like the
basic model. Those unpopulated spots for relays and some kind of suppressor (?) cap, make me think it would be straightforward to upgrade for basic thermostat control. Pity there are no pcb diagrams.
Various vendors selling these, with a choice of models rated for amperage/function. Seems the main manufacturer is Belgium/EU based.
Sentera is one of the leading manufacturers of HVAC sensors, fan speed controllers, logical controllers, potentiometers and frequency inverters.
www.sentera.eu
Found some pics here. Wiring model/options pamphlet.
Hi guys. Here it is http://img.tapatalk.com/d/14/03/18/asa5ydy4.jpg How do I wire it up? I take it I'll have to buy some 3 core wire and use the plug from my fan and hardware the fan into the controller? Here's the instructions lol http://img.tapatalk.com/d/14/03/18/me7uqy9u.jpg Can...
www.thctalk.com
The simplest route would be to just plug into an inkbird or similar, but then only have control of on/off for one selected speed.
Ideally it would be nice to utilise that pcb, to perhaps have control of two possible speed options.