Editing Brake (section)

==Types==
[[File:Drum brake testrender.jpg|thumb|Rendering of a drum brake]]
[[File:Bicycle caliper brake highlighted.jpg|thumb|left|Single pivot side-pull [[Bicycle brake#Caliper brakes|bicycle caliper brake]]]]
Brakes may be broadly described as using friction, pumping, or electromagnetics. One brake may use several principles: for example, a pump may pass fluid through an orifice to create friction:

===Frictional===
[[File:Impianto frenante.svg|thumb|typical braking system for cars:<br />
FAD: Brake disc front<br />
FPD: Brake disc rear<br />
FPT: Rear brake drum<br />
CF: Brake control<br />
SF: servo brake<br />
PF: Brake Pump<br />
SLF: Brake Fluid Reservoir<br />
RF: Splitter braking<br />
FS: Parking Brake]]
Frictional brakes are most common and can be divided broadly into "[[Brake shoe|shoe]]" or "[[Brake pad|pad]]" brakes, using an explicit wear surface, and hydrodynamic brakes, such as parachutes, which use friction in a working fluid and do not explicitly wear. Typically the term "friction brake" is used to mean pad/shoe brakes and excludes hydrodynamic brakes, even though hydrodynamic brakes use friction. Friction (pad/shoe) brakes are often rotating devices with a stationary pad and a rotating wear surface. Common configurations include shoes that contract to rub on the outside of a rotating drum, such as a [[band brake]]; a rotating drum with shoes that expand to rub the inside of a drum, commonly called a "[[drum brake]]",   although other drum configurations are possible; and pads that pinch a rotating disc, commonly called a "[[disc brake]]". Other brake configurations are used, but less often. For example, [[PCC trolley]] brakes include a flat shoe which is clamped to the rail with an electromagnet; the Murphy brake pinches a rotating drum, and the [[Ausco Lambert disc brake]] uses a hollow disc (two parallel discs with a structural bridge) with shoes that sit between the disc surfaces and expand laterally.

A [[drum brake]] is a vehicle brake in which the friction is caused by a set of [[brake shoe]]s that press against the inner surface of a rotating drum.  The drum is connected to the rotating roadwheel hub.

Drum brakes generally can be found on older car and truck models. However, because of their low production cost, drum brake setups are also installed on the rear of some low-cost newer vehicles. Compared to modern disc brakes, drum brakes wear out faster due to their tendency to overheat.

The [[disc brake]] is a device for slowing or stopping the rotation of a road wheel.  A brake disc (or rotor in U.S. English), usually made of [[cast iron]] or [[ceramic]], is connected to the wheel or the axle.  To stop the wheel, [[friction]] material in the form of [[brake pad]]s (mounted in a device called a [[brake caliper]]) is forced [[mechanical engineering|mechanically]], [[hydraulics|hydraulically]], [[compressed air|pneumatically]] or [[electromechanics|electromagnetically]] against both sides of the disc.  Friction causes the disc and attached wheel to slow or stop.

===Pumping===
Pumping brakes are often used where a pump is already part of the machinery. For example, an internal-combustion piston motor can have the fuel supply stopped, and then internal pumping losses of the engine create some braking. Some engines use a valve override called a [[Jake brake]] to greatly increase pumping losses. Pumping brakes can dump energy as heat, or can be [[regenerative brake]]s that recharge a pressure reservoir called a [[hydraulic accumulator]].

===Electromagnetic===
{{main|Electromagnetic brake|Regenerative braking}}
Electromagnetic brakes are likewise often used where an electric motor is already part of the machinery. For example, many hybrid gasoline/electric vehicles use the electric motor as a generator to charge electric batteries and also as a [[regenerative brake]]. Some diesel/electric railroad locomotives use the electric motors to generate electricity which is then sent to a resistor bank and dumped as heat. Some vehicles, such as some transit buses, do not already have an electric motor but use a secondary "retarder" brake that is effectively a generator with an internal short circuit. Related types of such a brake are [[eddy current brake]]s, and [[electro-mechanical brake]]s (which actually are magnetically driven friction brakes, but nowadays are often just called "electromagnetic brakes" as well).

[[Electromagnetic brake]]s slow an object through [[electromagnetic induction]], which creates [[Electrical resistance and conductance|resistance]] and in turn either heat or electricity. Friction brakes apply pressure on two separate objects to slow the vehicle in a controlled manner.