I guess lots of you still uses the old fashioned fan regulator like the one you see here. These fan regulators works with a copper coil as resistance to regulate the amount of current passing through to the fan. There is of course the speed dial ranging from 1 to 5 or sometimes 0 to 5 where 0 means it fan is switched off with no current passing through. 5 would mean all the current passes through offering no resistance at all. At speed level 5, the fan will be running at full speed. Anywhere in between 9 and 5 will offer a different range of resistance. The bigger the number, the more current will pass through and the fan will run faster.
The Internal OF a Fan Regulator
If you open up the cover of the fan regulator, you will see clearly the copper coil behind the speed dial. You will also see different strands of copper wires coming out from different parts of the coil and connected to their specified speed numbers. Of course, the more times the current travel round the coil, the more resistance it will meet, so less current will pass through, making the fan run at a slower speed.
Terminating this regulator wires simply means connecting the 2 wires to each of the ready terminal that you will see when you open up the cover of the regulator. Preferably, the live wire should go to the end with the smallest number and the switch wire to the terminal at the maximum speed. It will still work the other way round though.
Modern day speed regulators has done away with this old technology and has gone silicon. In place of the copper coil, transistors are used these days. The regulator looks more elegant and compared to the old fashioned type, they are very light weight, smaller and easier to install.