How to avoid lightning in electromagnetic flowmeter

2019-09-16
Thunder has become the biggest threat to electromagnetic flowmeters. Thunderstorm weather is the most
headache for enterprises using electromagnetic flowmeters. More than half of the electromagnetic flowmeter converters
are damaged by lightning due to thunderstorms. 
 
So how do we make the electromagnetic flowmeter converter lightning-proof?
 
The electromagnetic flowmeter can only be accurately measured if it has good grounding protection. In
an environment without such interference, the grounding does not affect the accurate measurement of
the flowmeter, but once the environment changes, the flowmeter cannot work accurately and stably. 
When installing, it is best to do sensor grounding protection to create a good working environment for
the electromagnetic flowmeter.
 
The electromagnetic flowmeter lightning protection method is as follows:
 
1. The signal cable length between the converter and the sensor cannot be greater than 50M, and the
signal cable must be sheathed with a galvanized pipe. If the galvanized pipe is in the air, the galvanized
pipe should be reliably grounded with a grounding resistance of less than 10 ohms.
 
2. The length of the grounding wire of the arrester should not exceed 1M, and the stranded copper core
insulated wire with a cross-sectional area greater than 6MM. If there is no ground net nearby, a simple net
should be made near the arrester. The method is as follows: three flat steels or angle steels with a length of
1.5M are used to drive into the ground in a regular triangle arrangement, and the flat steel bars are used to
weld the three flat steels. 
In one of the corners, the bolts are welded, and then the grounding wire of the arrester is connected to the
220 VAC lightning grounding plane to install the panel.
 
3. The power supply is 220v one-way AC, and an air switch is installed inside the instrument box. The arrester
and the air switch are connected in parallel. The wire is connected from the air switch and then connected to
a three-terminal socket.

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