Technical question - trailer emergency brake

1) yes... however initially charged and supplied by the trucks compressor.

2) im not really sure what youre asking... so click here

3) yes, if it has working spring brakes.

 

All air brakes are supposed to engage when pressure fails. It is a safety feature. Same on trains.

The air supply actually counteracts a spring in your airbrake cannister and compresses the spring releasing your brakes. When you step on your pedal you are allowing the pressure to bleed off.

 

Sorry, doesn't work that way. Although the cannister is one piece, the two lines operate two completely separate systems. You're right one line supplies air to a diaphragm and compresses a large spring to release the "parking brake". The other line supplies air at various pressures for brake application.(service brake)

 

When the driver pulls the button on his dash it drains the system. Otherwise the driver will get a nasty surprise when he goes to remove the glad hand connector between the truck and trailer (red and blue air lines).

 

No, it is not legal by DOT and EU laws. European trailer park valve differs, there are brake buttons on it. Why trailer park brakes are not directly connected to air tank... see answer to q #2

If supply (red) air line is disconnected trailer park valve dumps air from park spring brakes, but with some delay and wheels lock in some seconds. So if you pull red button in truck trailer park brakes will apply

 

Ouh, man, it was answer about old style trailers with ABS, newer TEBS, especially TEBS-E have some valves built in TEBS mosulator.

But in the USA simple ABS systems are popular and ABS modulator is combined with accelerating valve. As example - Wabco VCS and VCS-II.

As typical US trailer system http://www.wsafc.org/WSFMA/Shared Documents1/Bendix Air Brake Handbook.pdf

And about Wabco trailer ABS with air diagram http://inform.wabco-auto.com/intl/scripts/intl/pdf/815/00/08/8150100083.pdf