brake controller manual

Electro-Pneumatic Brake Controller for EMUs

Description Manual

Issue: 082012

Copy Right 2008© Knorr-Bremse AG. All rights reserved, including industrial property rights applications. Knorr-Bremse AG retains any power of disposal, such as copying and transferring.

Knorr-Bremse Group

of 11

Electro-Pneumatic Modular Brake

Controller for EMU

Description Manual


Description Manual

Issue: 082012


Knorr-Bremse Group

of 11

Contents

1. General Description

2. Description of Sub-assemblies

3. Drawing of EP Brake Controller


Description Manual

Issue: 082012


Knorr-Bremse Group

of 11

INTRODUCTION Electro-Pneumatic brake controllers are installed

in the driving cabs of trains fitted with Electro-

Pneumatic brake equipments to control the

application and release of both the E P and

pneumatic brakes.

EP brake controllers are suitable for controlling

EP brake equipment in which the magnet valves

are used for electrical brake control. The

pneumatic brake is controlled by a group of

poppet valves which, together with the self-

lapping elector-pneumatic mechanism and

equalizing discharge valve is housed in the brake

valve unit.

WORKING OF E.P BRAKE CONTROLLER Handle Positions:

Both the E.P and pneumatic brakes are controlled

by one handle. (Refer the installation drawing)

Selection between the two brakes is by handle

position. The E.P brake is controlled in positions I

& II and the Automatic brake in positions I, III and

IV. Both brakes (EP & Pneumatics) are applied in

position V (Emergency position),

Sub- Assemblies

There are three sub-assemblies of the brake

controller. The BRAKE VALVE UNIT, REDUCING

VALVE and ISOLATING VALVE SWITCH are

mounted on the controller pipe bracket.

Pneumatic connections between the valves and

the pipe brackets are made through ports in the

fixing flanges and bolting faces. The connections

are sealed by synthetic rubber gaskets. The

external pipe work is permanently connected to

the pipe bracket and compressed air is distributed

within the controller by passages in the pipe

bracket manifold.


Description Manual

Issue: 082012


Knorr-Bremse Group

of 11


Description Manual

Issue: 082012


Knorr-Bremse Group

of 11

OPERATION

E.P Brake Automatic Brake

Operation of E.P. BRAKE (Position I, II & V) The E.P brake is an electrically controlled ‘straight air’ brake which admits compressed air to the brake cylinders under the control of two magnet valves on each of the vehicles of a train. All the magnet valves and brake controllers are connected by train wires. Movement of the brake controller handle is between positions I and II. It switches the electrical supply onto the train wires to energize the magnet valves in sequence. One of the two magnet valves – the ‘Holding’ magnet valve – closes the brake cylinder exhaust when it is energized and the other – the ‘ Application’ magnet valve – admits compressed air from the main reservoir supply to the brake cylinders, when energized. The degree of braking is determined by the amount of handle movement from position I. Maximum E.P. service braking is obtained with the handle in position II. Release and Running Position I (Fig. N) When the brake controller handle is in position I. (a) The Holding circuit is open (All holding magnet valves open; brake cylinders vented) (b) The Application circuit is open (All application magnet valves closed to prevent compressed air from entering the brake cylinders) Both the E.P. and Automatic brakes are released; the brake pipe and equalizing reservoir are maintained charged to the pressure at which the reducing valve has been set. Partial Application and ‘’Self Lapping’’

Handle moved to a position between positions I and II. Full Service E.P Position II When the controller handle is moved to position II the E.P. brake is applied to the maximum brake cylinder pressure – usually determined by the limiting valve on the brake unit. The direct acting contacts, connected in parallel with the self-lapping contacts, close and keep the Application and Holding magnet valves energized until the handle is moved back into the ‘Release’ Position or self- lapping range. Self-lapping does not have any effect in position II. Emergency Position V In position V the self-lapping and direct acting contacts are closed in exactly the same way as in position II and the Automatic brake is also applied pneumatically. Automatic Pneumatic Brake The Automatic brake is controlled by varying the air pressure in the brake pipe which is a pipe carried throughout the length of the train. The brake pipe is charged with compressed air delivered at constant pressure by the pressure reducing valve mounted on the controller pipe manifold. The Automatic brake is applied by discharging air from the brake pipe and released by restoring the air pressure in the brake pipe. A triple valve (available on EP brake unit) on each vehicle is connected to the brake pipe and applies or releases the automatic brake in response to the brake pipe pressure variations The Automatic brake can be applied in stages but Do NOT get release gradually.


Description Manual

Issue: 082012


Knorr-Bremse Group

of 11


Description Manual

Issue: 082012


Knorr-Bremse Group

of 11

FUNCTIONS OF SUB ASSEMBLIES Equalizing Discharge Valve The Equalizing Discharge Valve reproduces in the

brake pipe the pressure reduction made in the

equalizing reservoir during service applications of

the Automatic brake.

Space above the diaphragm, is connected to the

equalizing reservoir; space below the diaphragm,

is connected to the brake pipe. When the

equalizing reservoir pressure (above the

diaphragm) is reduced, the brake pipe pressure

lifts the diaphragm, opens valve and releases air

from the brake pipe.

As the diminishing brake pipe pressure

approaches the (reduced) equalizing reservoir

pressure, the pressure difference above and

below the diaphragm diminishes also, the

diaphragm moves downwards and gradually

closes valve. The tapered shape of the valve

assists in preventing abrupt closure which might

set up undesirable pressure surges in the brake

pipe.

Pressure Reducing Valve

The pressure reducing valve delivers compressed

air from the main supply, at a constant reduced

pressure, to the Brake pipe. The flow of air from

the high pressure connection to the low pressure

connection to the low pressure connection is

controlled by a piston operated slide valve. The

piston movement is governed by a small pilot

valve which is opened and closed by the action of

metal diaphragm balanced between brake pipe

pressure on its upper surface and a spring on its

lower surface. The compression of the spring can

be varied to adjust the output pressure.

Isolating Valve Switch The Isolating valve switch isolates controllers both electrically and pneumatically at non-operative cabs. 1. The pneumatic valve assembly contains three spring loaded poppet valves operated by a cam and rocker mechanism turned by the operating spindle. 2. The electrical switch consists of three contact drums, also turned by the operating spindle, and contact fingers arranged in three banks. There are also two junction terminals. The operating crank fitted to the spindle where it protrudes through the controller casing, is shaped to receive a key. In the ‘open’ position the valve sets up the pneumatic and electrical connections to make the controller operative and in the ‘closed’ position it isolates the controller. A spring loaded plunger located in the recess of the cam to give a positive stop in the ‘open’ and closed’ positions. The terms ‘open’ and ‘closed’ refer to the air connections.

brake controller manual

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