Chapter 2 - General Safety Precautions
Medha Servo Drives Pvt Ltd.
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RUN digital Input signal), the parallel Brake Grid path is connected
to the DC LINK by four Braking contactors (B1, B2, B3, B4). This
method discharges the DC LINK capacitors in less than ONE second.
3. Brake Chopper and Hard Crow Bar
Whenever the DCL V >= 2800V Brake Chopper fires to bring the
DCL V to <= 2600 V, if the DCL V >= 3000 V TCC Lockout the
operation of Inverters, and the DCL V >= 3400 V Locomotive
Control Computer fires Hard Crowbar, at DCL V >= 3600 V HW
Fires Hard Crowbar. Automatically recycling of DCL switch gears
when DCL Voltage decoys, if there was no other Crowbar event in
last 10 minutes.
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After the DC LINK has been discharged by braking grids or the brake
chopper or crow bar, the DC LINK Contactors moves to the open
position. Moving all the DC LINK switch gears to the open position
causing all Traction Inverters to be shorted and grounded with busbar
connected to connectors of the DCL contactors.
a. When the Engine is shutdown (regardless of the Isolation switch
position) the control computer picks up all the Braking contacotrs,
the DC link Voltage dissipate through grid resistors. Once the DC
LINK capacitors are discharged, DCL contactor moves to open
position.
b. Whenever the Battery Knife switch or Local control circuit breaker
is opened, the LCC detects the loss of Local control or Knife
switch and moves all DCL contactors to shorted position. Indian
Railways Electrical Control Cabinet 1 comprises of all electrical
controls of the locomotive along with Locomotive Control
Computer.
