Electric brakes are commonly used in conjunction with RV trailers. In this application, they are normally match with standard automotive braking component construction.These components can perform to the manufacturer's specifications provided that the followng points are adhered to:
In some instances these brakes could cause a problem when used in conjunction with boating trailers, particularly using the wet launch boat trailer application, particularly in salt water launching.
Trailers and caravans towed by light vehicles including SUV/Pick-up must have a braking system if the trailer gross mass exceeds a certain value as determined by some legislative bodies/Government. An electric braking system is commonly used to activate the drum-type friction brakes on the trailer.
Braking effect can be increased or reduced by the driver, adjusting a control unit to suit the load on the trailer.
When the brakes in the towing vehicle are applied, the brake-light circuit sends the signal to the control unit. The control unit then sends an appropriate current to the trailer brake actuators, to operate the trailer brakes, at the level selected. This should be appropriate for the loaded conditions of the trailer and the relative speed.
Legislative Background
Many legislative jursidictions around the world have varying requirements for auxilliary braking for trailers and so forth.For instance, one jurisdiction has the following legislative requirement enacted:
"All trailers with a Gross Trailer Mass (GTM) exceeding 750kg (1650 lbs) and first registered after 30 June 1990 are required to be fitted with an efficient braking system. For trailers with a GTM of up to 2 tonnes (2.2 ton),this braking system can be either an overrun sysytem or one that is operated from the driver's seat.
For trailers with a GTM exceeding 2 tonnes (2.2 ton), the braking system must be capable of being applied from the driver’s seat - overrun brakes are not acceptable. In addition, the braking system must be such that if the trailer accidentally breaks away (from the towing vehicle), the trailer brakes will apply automatically and remain applied for at least 15 minutes''."
Selection of Braking System
When selecting the appropriate electric brake components for your trailer, consideration must be given to:
For multi-axle trailers, consideration to the number of axles that will be equipped with brakes to meet the vehicle and its combination's stopping requirements.
Electric brake systems consist of components mounted both on the tow vehicle and the trailer. An electric brake controller must be properly mounted in aconvenient location within the vehicle. The trailer side of an electric brake system consists of left & right electic brake components, drum & hub assemblies, EMERGENCY BREAKAWAY KIT-(battery w/box, breakaway switch, trickle charger) and end plug connector.
Basic Componentry
Brake Control Unit
All electric brake systems require a brake controller to apply power to the brake system. With the majority of electric brakes, as power is applied to the electromagnets in the brake cluster, the magnets are pulled to the interior flat surface of the hub drum. As the wheel and drum turn during highway travel, this attraction of the magnet to the flat drum face pulls the lever arm of the brake actuating cam, rotating the cam and forcing the brake shoes out to contact the drum braking surface. The more power applied to the magnets the greater the leverage on the came resulting in greater braking response.
As a safety overview, most installers locate the electric brake controllers on or near the dash allowing the driver access to the manual override button. As with any auxilliary braking component, it must have a manual override button allows the driver to activate the trailer brakes without operating the tow vehicle braking system. This can be important if your trailer is prone to sway. Some compoent manufacturers have suggested that, by bumping the electric brakes on the trailer during sway, the driver can dampen and control sway problems should they occur.
Major Disadvantage for Electric Auxilliary Brakes
If you use a dash mounted brake controller, you must have a controller on every vehicle that you tow the electric brake equipped trailer with.
Electric brake controllers come in a variety of types:
Source: CDX Global & Wikipedia - en.wikipedia.org
