HCMT Electrics Flashcards
Overview of train electrics
Where are the Pantos located?
Number one end of all motors
What type of process raises the Pantos electric pneumatic or mechanical?
Electric & pneumatic
What main reservoir pressure is required to raise the Pantos when the cab is activated
700 KPA
What level of power is available from the batteries to power and auxiliary compressor which raises the local Panto?
110V DC
At what main res pressure will the Pantos on the DMp cars raise automatically?
400 to 450 K PA
Where is the high-voltage box located and what is contained in it?
No. 1 end of all motors and it contains the high Speed circuit breaker and harmonic wave detection device
What is the purpose of the high Speed circuit breaker?
The HSCB protects the traction inverter from further damage if there was a fault by tripping.
- Extra info …If this happens, you might get an alert, which is a level one or level two on the HMI to let us know.
- The TCU/ACU reset push button can be used to reset the HSCB when prompted by the TMS it is located in the electrical cabinet on the A side of the cab.
What does the harmonic wave detection device HWDD do?
Protects against power quality problems
due to harmonic currents generated from either the traction system, or from the overhead contact wire
When does the harmonic wave detection device cut off power to both traction and the auxiliary inverters?
When a preset threshold limit of harmonic, frequency is exceeded by two seconds, or more
if it detects 3 consecutive breaches over a period of 1 minute, the traction and auxiliary contactor will remain open indefinitely
What does the electrical auxiliaries system do?
The overhead 1500 V DC provides power to the auxiliary inverters in the auxiliary power supply unit.
This convert 1500 V DC into 415 V AC that powers, the
battery charger,
main compressors
HVAC’s and the
traction cooling system
What does the battery charger do?
Convert 415V AC in 110V DC that charges the battery and provides power to auxiliary loads
What does the vehicle traction system do?
Traction power comes from the overhead via the high-voltage box, which supplies 1500V DC to the two traction inverter modules located in the variable voltage variable frequency cabinet.
This, then provides three phase power to the traction motors
What are the two main functions of the vehicle traction system?
Providing traction combined with electrical braking
Collecting electrical energy from the overhead and transforming to different voltage levels
How many Traction inverter modules are in the VVVF Cabinet?
2
What do the brake resistors do?
Release the energy generated from the ED braking
How are Traction faults reset in the traction inverter?
The reset, automatically through the inbuilt system fault protection
What will happen if the traction inverter has a repetition of faults within a certain timeframe?
It won’t be automatically reset. The traction inverter will be locked and a manual reset becomes required.
How are some faults such as overvoltage, overcurrent, and module failures dealt with?
They can be reset via the TCU APS reset push button the driver will be prompted via TMS
When is the driver able to use the TCUAPS button?
Only if prompted by the TMS and authorized by the train controller
What is the purpose of the auxiliary inverter?
Convert 1500 V DC into three phase 415 V AC to power all AC loads. 240 V AC to cabin saloon GPO’s
What does the medium voltage box do?
Maintains the 415 V AC train bus that runs the length of the train
How many cells in the battery box and how many volts?
80 cells provide 110 V DC
What if there is a fault or failure on one battery set?
The other battery sets can supply 110 V DC to the train line
How long does each train have sufficient battery power to restore normal functions?
There is enough power, even After supplying emergency power for 2 hours
What does the battery charger do?
The battery charger convert three phase 415 V AC to 110 V DC power to the auxiliary loads
What makes up 415 V AC equipment that is relevant to the driver?
• Battery chargers
• Air compressors (main compressor)
• Traction equipment cooling systems
• HVAC - cab and saloon
What makes up 240 V AC equipment
General power outlets, (cab and saloon)
110 V DC equipment
Safety loop
Brake and traction commands.
Driver control
Marker lights
Communication systems
CCTV
TMS/ eTIS / event recorder.
Door controls
Smoke detection
Event recorder.
Saloon lighting.
Cab lighting.
Auxiliary compressor
Electrical auxiliary power supply
What is the definition of permanent loads?
Always connected to the battery whether the cab is activated or not
What is the definition of non-permanent loads?
These loads can only obtain power from the batteries when the cab is activated
What is the definition of emergency loads?
Emergency loads can be either permanent or non-permanent, which will have power during emergency conditions where a battery charging system has failed or due to the loss of overhead
What functions will be reduced during emergency conditions and what will the battery sets power voltage be and for how long?
All 110 V DC equipment for approximately two hours
reduced functions include:
• Saloon lighting, reduced to 50% of normal brightness after 10 minutes
• HVAC fresh air fan operates with 110 V DC battery power for at least 2 hours
• Saloon door controls will operate as normal
What are the fresh air dampers that attached to each HVAC unit do?
They vent fresh air into the train
What temperature can be set in the cab regardless of external temperature?
Between 18 and 26°
What kind of temperatures are achieved in 30 minutes ?
Internal temperature of 18° regardless even if it’s zero outside.
26° inside even with an external temperature of 40°C
When the train wash motor selected what will happen to the fresh air dampers ?
The HVAC unit closes the damper and stops the fresh air fan
What is setback mode?
It’s like a standby mode that reduces power consumption by 50%
Used when neither Cab is activated
Only one HVAC per saloon will operate.
Only one refrigeration circuit / one heating bank will operate in the cab, HVAC unit.
What happens if one HVAC unit on the saloon fails?
The other HVAC will continue to operate
What will occur in the event of internal smoke detection?
- The internal detector relays a signal to the 2 HVAC units on the car
- level 2 alert & 15 sec timer will begin
- after 15 sec alert will escalate to level 1 & initiate smoke mode
- HVAC units will shut down operation and open the fresh air dampers. The internal fire doors will also close.
HVAC’s send a confirmation to eTIS that Smoke mode has been activated
How many external smoke detectors must detect smoke on a car to trigger the HCMT into external smoke mode
2
What are the four miniature circuit breakers That will disable the train if they’re tripped?
- Cab activation.
- Train control.
- Emergency brake loop power supply.
- Brake control supply
What is the effect on the train when cab activation MCB is tripped?
Unable to drive from that cab - disabled
What is the effect on the train when traction control MCB is tripped?
Train disabled, BCU and TC. You do not receive any direction from the reverser & master controller.
What is the effect on the train when emergency brake loop power supply, MCB is tripped?
When tripped at both ends emergency brake supply, and cannot be released. Train is disabled.
What is the effect on the train when brake control supply MCB is tripped?
Train is disabled ,
affects BCU status monitoring only if both CB’s were tripped,
holding brake, won’t release
loss of park brake control
recovery mode switch inoperative
local get home inoperative
local zero speed input inoperative
How many times my drivers attempt to reset a tripped, miniature circuit breaker
Maximum of two times
How will the Safety Loop de energise?
When there is a loss of power
Or
because one of the components is not set correctly, then the emergency brake will apply
When will the emergency brake apply in connection to the safety loop de energizing?
-MC handle is placed into EMY position
- Hand and foot Paula valves are not set for a certain time when moving
or not set, & the MC has less than 50% brake application when stationary - ESB pressed
- Trip activated
– vigilance, penalty application
– MR below 600 K PA
– towing unit demand for EMY brake
Dash safety system bypass reminder timer.
– physical interruption of the safety loop e.g. train separation
When can the safety loop be reset?
The train is stationary more than 3 seconds
The reason for the EMY brake application has been reset
MC to max brake and reverse it to neutral, and then back to FWD
