76 Chapter 6 Maintenance
NetSure 801 CA7 Power Supply System (New Skelecton) User Manual
No.
Item
Test standard
Test tools
Test method
8
Noise index
Psophometrically weigthed noise ≤ 2mV;
peak
– peak noise ≤ 200mV
Noise meter,
oscillograph
During noise measurement, the batteries
should be separated from the power
equipment. However, for the sake of
safety of power supply, the batteries
cannot be disconnected during field
operation. Therefore, this test should
only be done when the communication
quality of the exchange is poor and the
power supply quality of the power
equipment is considered not in
conformity with requirements. The
psophometrically weigthed noise, input
through through the positive and
negative busbar, can be measured by a
noise meter, which shall be geared to
“telephone noise” measurement scale.
The peak
– peak noise can be
measured by an oscillograph. For test
method refer to the equipment operation
instructions
9
Internal connection
The socket shall be well connected; the
cables shall be well laid out and fixed;
there shall be no cables that have been
squeezed out of shaped by metal
components; and there shall be no
partial overheat or aging of connection
cables
10
Vent duct and dust
deposit
There shall be no blockage or dust
deposit in the vent ducts of rectifier fans
or vent ducts in the cabinets
Hairbrushes,
leather bellows,
etch
Remove, clean and wash the guard
boards of the vent ducts and the fan;
replace them after they have been dried
11
DC cables
The permissible voltage drop determined
in circuit design is generally less than
0.5V (low impendance distribution)
Note down the maximum current flowing
through the cables, look up the sectional
area and wiring length of the cable in the
design plan, calculate the voltage drop
and check whether it meets the design
requirements
12
Configuration of
DC circuit breakers
The rated current of the DC circuit
breaker should not be more than twice of
the maximum load current. The rated
current of the circuit breaker in each
special equipment room should not more
than 1.5 times of the maximum load
current
Check the adaptability of the circuit
breakers according to the recorded
maximum current of each load
13
Voltage drop and
temperature rise of
nodes
If below 1000A, the voltage drop should
be
≤ 5mV for every hundred ampere; if
above 1000A, the voltage drop should
be ≤ 3mV; and the temperature rise of
node should not exceed 70°C
Multimeter,
semiconductor
thermometer
Use multimeter to measure the voltage
drop between the buses and cables at
the two terminals of the node; and judge
the rationality of the voltage drop of the
node based on the current flowing
through the node. Use the
semiconductor thermometer to measure
the temperature rise of the node. The
measurement results should meet the
temperature rise limitation and voltage
drop limitation requirements