Anti Spin Brakes
The principal of the anti-spin brake is to provide the traction equipment, with means to obtain a rapid yet light brake application to the driving wheels. The friction thus generated between the brake shoes and the tyres immediately absorbs the torque, which is in excess of the value that can be absorbed by the normal adhesion between the tyre and railhead. The net result is to prevent any increase of existing wheel slip.
The principal advantages are that the slip is prevented or controlled, so avoiding the possibility of damaging the traction equipment, and at the same time it normally enables the traction power to be maintained so improving and simplifying the control of the locomotive when operating under conditions which may cause wheel slip.
The anti-spin brake can give an improved adhesion condition between the rail and tyre, due to the cleaning effect of the brake shoe when used with ‘On tread’ braking.
A further important advantage of the anti-spin brake is that its use often enables a reduction in the use of sanding. This device is provided on each bogie behind MCP.
The automatic anti – spin protection is initiated as soon as the ratio between effective tractive/braking effort and requested tractive/braking effort is less than 0.5
As required, one or more of the following actions is/are initiated:
- Sanders start
- LSP glows
- TE/BE difference is reduced by control electronics.
- If necessary required braking force is given to wheel by applying loco brakes by control electronics- you can see that BC needle ups and down. (Which is limited to 0.6 kg/cm2 to 1.0 kg/cm2?)
Note :
1-If anti spin brakes are not applied at the time of wheel slipping, then wheels will get off loaded and to avoid further spinning, CE will reduce tractive effort. This will affect the hauling of load
2- When train is in motion with speed more than 10 KMPH, Start/Run interlock get activated if BC pressure rushes above 0.6 kg/cm2 and TE becomes 0.
On run during anti spin brakes, 0.6 kg/cm2 to 1.0 kg/cm2 pressure rushes in brake cylinder. So as per above, due to this 0.7 kg/cm2 pressure TE get reduced to 0 affecting haulage of load. P/ZRTI-BSL 54 3-Presently as per RDSO’s instructions anti spin brakes are isolated on the locos to avoid TM failure.
Brakes Through Blending Valve:-
If train is running in regenerative (DBR) mode and suddenly regenerative braking gets cut off automatically due to internal fault or VCB tripping, to compensate regenerative braking, blending valve send the MR pressure in the brake cylinder in proportion. This pressure activates the relay valve (57), further this relay valve allows MR pressure into BC.
Synchronous loco brakes:-
Whenever BP pressure drops below its pre- determined value (5 kg/cm2 ), distributor valve gets activated and allows MR pressure to activate relay valve (57),further this relay valve allows MR pressure to rush in brake cylinder (2.5 kg/cm2 ). Like this, when BP restores, DV gets balanced and releases the brakes accordingly.
Parking Brake:-
In 3-phase loco, hand brakes are not provided. For parking the loco a new type brakes are available on this loco, called parking brake. The great feature of parking brake is that, it remains applied to indefinite time as per your requirement in absence of air pressure. Its function is just opposite to that of conventional brakes. i.e. it remain release when there is 6 kg/cm2 pressure in parking activator and get applied when pressure exhausted below 3.8 kg/cm2 in parking activator. But the brakes are applied through the same brake block of conventional loco brakes.
Parking brakes are provided on Wheel No.2-6-7-11 (WAG9/WAP-7) and on wheel no. 1-4-5-8 in WAP-5 loco.
Applying Parking Brake
1. Press push button BPPB, a red lamp illuminated in it. Due to which 6 kg/cm2 air in parking activator get exhausted and the PB gauge show ‘0’ kg/cm2 which indicates the application of P.B. (this is possible only when CE is ON) OR
2.Press ‘Apply’ push button solenoid valve-30, BPPB red lamp will glow, P.B. pressure gauge show ‘0’ kg/cm2 and PB get applied. (This is possible when there is MR / AR pressure in the loco and lamp will glow if CE is ON) OR
3.When ‘BL’ key is moved from ‘D’ to OFF parking brakes get automatically applied through control electronics. BPPB will not be illuminated since CE in OFF but P.B.gauge will show “0” kg/cm2
