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- description "Substation 18 month exam
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- fileName "18 month review"
- freezingBlueDBID -1.0
- Explain clearance procedures starting from switching through grounding.
- The request process, switching, issuance of the clearance, test the circuit, ground the circuit, explanation process, actual work, clearing of men, removing grounds, releasing clearance, and switching.
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Name all forms involved in clearance.
260 clearance, 105 red tag, 182 switching.
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Explain the rail return system. What would you need to work on it?
A combination of jumpers cables and impedance bonds that provide an electric path from train to substation. You need a jumper.
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What is a section break?
A point where 2 circuits are separated while providing continuous power.
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What is a phase break?
A point where 2 power sources are separated.
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What are the load dispatchers duties?
He Monitors and regulates power demands.
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What are the power directors duties?
He is in charge of the power system within an assigned territory.
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Prior to grounding transmission lines what steps must be taken?
Obtain power clearance and visually check the air break is open and ground switch is closed at the substation.
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Grounds for caternary should be no less then what size cable?
4OT
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Grounds for signal lines should be no less then what size cable?
2OT
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What is an impedance bond?
A device that separates signal power from traction return.
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What would occur if 1 leg of signal line would go to ground?
There would be a ground detected.
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What would occur if both legs of signal line would go to ground?
The breaker would trip.
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Name 4 things to check for while doing a substation inspection.
Targets, trolly voltage, battery voltage, and station ground.
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What device would measure the flow of oil through cooling equipment on a transformer?
An oil flow gauge.
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What is the difference between synchronous speed and full load speed of a motor?
Slip of the motor.
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What are the ratings for our step down power transformers?
45000 kva
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What are the ratings for our potential and service transformers?
Potential 200 va / service
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Draw the configuration of an additive and a subtractive transformer.
H1. H2. H1. H2
- X2. X1. X1. X2
- Additive. / subtractive
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What is control battery voltage?
132 - 140 volts. Dc
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What do we use to charge the batteries in the substation?
Battery charger.
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When receiving a clearance on a bus section in a sub with only one potential transformer what must be done before receiving the clearance?
Switch power to other PT (power transformer)
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What are the feeder breakers of the signal system?
252
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What is the voltage and frequency of the 152 contactor ?
480 volts. 100 Hz
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Ratio of output power to input power of a motor is what?
Efficiency
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Describe the CR relay
Reverse current relay, trips the low side.
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Describe the CA relay
Internal fault relay trips the low and the high side
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Describe the CO balance
Line to ground relay, trips the low side
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What is the JD what relay does it work with?
Timed relay that protects the bus, it works with the CA4 ( will trip the bus in 1.25 Sec if CA4 does not do its job)
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What is a relay that operates in response to an expanding Bi metal?
Thermal relay
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Power transformers used by Amtrak are what configuration?
Delta wye
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What are the primary and secondary voltages of a heater station?
Primary is 12 kv / secondary is 480 V
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What is the main breaker of a heater station rated?
1200 amps
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What are the secondary breakers rated?
400 amps
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What are Amtraks trolley breakers rated for?
1500 amps
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What is a current transformer what does it do?
It provides current for the meters and relay equipment. It brings current down to a readable amperage.
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What are the secondary wires of a CT what are the hot legs ?
F, ff. S, ss
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What are the following relays? 27 and 230
- 27 is under voltage relay
- 230 is lockout relay
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What is "A" contact?
Normally closed contact.
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What is a rectifier?
It changes AC to DC
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What is an inverter?
It changes DC to AC
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Before working on a lightning arrestor what must be done?
Discharge
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Before working on a trolley breaker what must be done?
Discharge and remove DC
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What is a megger how does it work?
An instrument that uses high voltage to test the insulation value of wires.
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