power supplies Flashcards
Commercial power that feeds our power supplies and home are _______ or ________ VAC
120 or 240
Commercial power that feeds our power supplies is ______Hz
60
Commercial power that feeds our power supplies is a _________ wave
Sine
3 battery power supplies have a voltage of ______
36V
What changes the DC battery volts to VAC?
Power Supply Inverter
What changes the input VAC from 120V or 240V to 60V or 90V output?
Step Down Transformer
What device combines the PS voltage with the network RF signal?
LPI (Line Power Inserter)
SPI
Service Power Inserter
What devices are used to direct AC power?
Fuses or Shunts
This device has a low pass filter on each leg, this prevents RF leakage in the Power Supply
LPI (Line Power Inserter)
Powering architecture where there is only one power supply used to power the entire node and actives
Centralized powering
this power architecture is the most commonly used
distributed powering
Center Conductor Resistance + Sheath Resistance
DC Loop Resistance
Span current X Span resistance
Voltage drop
Voltage difference between batteries should be no more than:
0.3VDC
Battery terminals should be protected w/ corrosion inhibitor like NO-OX or NCP-2, True or False
True
Before disconnecting the batteries always turn off the _______ ________ first
Battery Breaker
Use a ________ to accurately measure power supply output VAC
True RMS Volt Meter
The most accurate & Reliable way to test batteries is to test them under _______ Conditions
Load
When testing with a load tester, batteries should or should not be disconnected
Should
Power supply batteries produce what gas when charging?
Hydrogen
Powering architecture where there is more than one power supply feeding the node and actives
Distributed power
Divide and conquer means
Cut the problem in half
The purpose of divide and conquer is to
Reduce Repair time
A frequency selective volt meter
SLM (Signal Level Meter)
two most commonly used pieces of test equipment
SLM & VOM (or DMM)
The majority of outages are _______ related
Power
TDR
Time Domain Reflectometer
In a terminated cable with no faults, the TDR energy is absorbed meaning there is _________ reflected energy
NO
Correct ________ is needed for correct TDR Measurements
VOP (Velocity of Propogation)
Resistance to AC is called
Impedance
two types of TDRs
Waveform & Digital
VOP
Velocity of Propogation
this is caused by the time lag needed for the TDR pulse to enter the cable
Dead Zone
use a ________ ________ to minimize the effect of a dead zone
Launch Jumper
The most accurate way to find a fault with a TDR is to
TDR from both ends and divide the difference in half
A TDR trace with the same polarity
Open
A TDR Reflection with the opposite polarity
Short
a properly terminated cable will _______ the TDR pulse energy
absorb
Locate colors-Power:Gas:Telecom:Water:
Redyelloworangeblue
Sending AC from two different power supplies to the same point
Bucking Power
A low resistance connection between two points in an electric circuit
Shunt
used to direct power in the CATV network
shunts & fuses
In the return path, the pads and EQs are insalled on the ________ side of the return amplifier to provide flat inputs to the next upstream amplifier
output
cumulative effect of the return path distortions
funnel effect
CPD beats fall _____ apart in the upstream
6MHz
In the forward path, CPD contributes to ______ distortions
CTB
Return path noise caused by arching electrical motors
Impulse Noise
Trenches greater than _______ feet must be shored to prevent cave ins
4ft
In coax, the attenuation of the reverse signals is _______ than that of the forward signals
Less
