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127
You can refer to the following sheet for the file size in one hour per channel. (All the data listed below are
for reference only.)
Bit stream size (max)
File size
Bit stream size (max)
File size
96K
42M
128K
56M
160K
70M
192K
84M
224K
98M
256K
112M
320K
140M
384K
168M
448K
196M
512K
225M
640K
281M
768K
337M
896K
393M
1024K
450M
1280K
562M
1536K
675M
1792K
787M
2048K
900M
Appendix B
Earthing
1.
What is the surge?
Surge is a short current or voltage change during a very short time. In the circuit, it lasts for microsecond.
In a 220V circuit, the 5KV or 10KV voltage change during a very short time (about microseconds) can be
called a surge. The surge comes from two ways: external surge and internal surge.
⚫
The external surge: The external surge mainly comes from the thunder lightning. Or it comes from the
voltage change during the on/off operation in the electric power cable.
⚫
The internal surge: The research finds 88% of the surge from the low voltage comes from the internal
of the building such as the air conditioning, elevator, electric welding, air compressor, water pump,
power button, duplicating machine and other device of inductive load.
The lightning surge is far above the load level the PC or the micro devices can support. In most cases, the
surge can result in electric device chip damage, PC error code, accelerating the part aging, data loss and
etc. Even when a small 20 horsepower inductive engine boots up or stops, the surge can reach 3000V to
50000V, which can adversely affect the electronic devices that use the same distribution box.