There is a positive wire from your battery to the trailer socket on the rear of your vehicle the controller sits in this line and varies the amount of current that can go to the socket based upon a number of factors, the setting the driver makes on the controller and for some types the G-Forces involved in the decelleration. The higher the setting/more G-forces the greater the current sent to the socket. Everething is activated by an electrical tap into the stop light switch/wiring.
For the trailer side, (mostly) you have special drum brakes on the trailer, they have both smooth braking surface for the shoes, just like normal drum brakes, and also the back of the hub is machined flat. A pair of electro-magnets are mounted close to this flat hub back. When current is applied to the electro-magnets they try to clamp onto the drum but because of the rotation of the wheels the magnets are rotated slightly within the drum, this movement drags on a mechanism connected to the shoes forcing them onto the braking surface of the drum. The more current applied the harder the magnets clamp and the more mechanical (braking) effort is applied to the shoes.
Electric drum brakes don't work in reverse and the mechanisms are sided.
Bookmarks