Electrical Systems Flashcards
metrorail has ___ distinct type of electrical systems
3
in the metrorail system, the most important electrical system to the fire service is the traction power system, which is used to ___________
propel the rail cars
the second electrical system that is important to the fire service provides electrical power to run lighting, ventilation and any other type of service that does not propel the car. this system is a ______power system
AC
the emergency power on the metrorail service is provided by _________ power
battery
battery power can be found when emergency lighting is needed along with the ________ system
communication
a conductor is used to supply power to propel rail cars. the conductor is also known as the __________
third rail
The third rail which is converted from AC power to DC power producing _____ volts
750 volts
the redundancy of each traction power substation is provided by _____ separate feeders
2
pepco supplies _______ volts of power to metro traction power substations
13,800
normally, traction power substations can be found every ________ throughout the metrorail system
mile
the transformers contain a coolant that does not contain any __________
PCB’s
the transformers are located in concrete or block structures with a minimum fire rating of ____ hours
2
each transformer is monitored by a sophisticated system that can be shut down the transformer within _______ when a problem arises
30 milliseconds
the third rail is _____ inches higher than the running rails
4 1/2”
once you pick up the telephone in the ETS box, you dial _____ to talk to OCC
0
one should not confuse the volt probe prong color that touches the third rail and WSAD paddle that touches the third rail. both are colored ________
red
the pot heads are what color
orange and yellow
the grey protective cover located over the third rail is rated at _______ lbs per inch of force
250
the max length of third rail section is
800 ft
power removal of the third rail can be done two ways ________ and ________
ETS and OCC
when testing the third rail with the volt probe, what do you do first?
red probe to running rail
an ETS box (blue light station) has an emergency push button that is colored _______
red
testing the volt probe can be done by using the 110 volt receptacle located under every other ________ in the tunnels, under every other ______ on the station platform, the walls and occasionally in the floor of ______ platforms
fluorescent lights, bench, station
what is recommended if the volt probe shows that the third rail power is down?
retest on a known electrical source
if a paddle on the WSAD falls off the ______ will activate
warning horn
if the WSAD activated during use or restoration of third rail power, it shall be returned to Metro via ________
the metro liaison officer
when OCC receives a call from the ETS box to shut electrical power down, OCC complies buy shutting power down utilizing computer control. this is known as ________
supervisory power outage
ETS boxes are located every _____, and at ________of each metro station
800 ft, each end
the ETS (emergency trip switch) should only be used when it’s ____________
immediate threat to life safety
in stations emergency battery power will supply lighting and communications for up to ______ hours
3
when emergency power is being used every _____ light above the safety walk will be powered
4th
when emergency power is being used _____% of the lighting above the safety walk will be powered
25
“stray current” moving between the rail car can be as high as ______ volts
60
In regards to “stray current, rail cars and the rails may contain as much as ______ volts after power is shut diwn from the third rail.
60
