Electromagnetic Flowmeter COPA-XT
7
3.3
Electrical Connections
3.3.1 Grounding
The ground connections described herein are to be observed.
In accordance with VDE 0100, Part 540 a Cu-wire with a cross
section of at least 4 mm
2
is to be connected between the
ground screw on the flowmeter primary (at the flange or the
converter housing) and ground. Grounding of the converter is
essential in order to achieve EMC-Interference resistance. For
measurement reasons the potential of the ground should be the
same as the pipeline potential. An additional grounding at the
connection terminals is not required.
For plastic pipelines or pipelines with insulating liners the
ground connection is made to a grounding plate or grounding
electrode. If there are stray currents present in the pipeline, a
grounding plate up- and downstream of the flowmeter primary
is recommended.
Three grounding methods are describing in the following. In
examples a) and b) the fluid is in electrical contact with the
pipeline. In examples c) and d) the fluid is insulated from the
pipeline.
a) Metal Pipeline
1) Drill blind holes into the flanges
(18 mm deep).
2) Thread the holes, (M6 = 6 mm).
3) Using a screw (M6), spring washer and flat washer attach
the ground strap and connect it to the ground connection on
the flowmeter primary.
4) Connect a 4 mm
2
Cu-wire between the ground connection
on the flowmeter primary and ground.
b) Metal Pipeline with Loose Flanges
1) In order to assure problem free grounding of the fluid and
the flowmeter primary in pipelines with loose flanges, a
6 mm threaded stud should be welded to the pipeline.
2) Using a nut, spring washer and flat washer attach the
ground strap and connect it to the ground connection on the
flowmeter primary.
3) Connect a 4 mm
2
Cu-wire between the ground connection
on the flowmeter primary and ground.
Fig. 11
Wafer Design Primary 3/8”-4” [DN 10-100]
Fig. 12
Flanged Primary 3/8”-4” [DN 10-100]
Fig. 13
Wafer Design Flowmeter Primary
Fig. 14
Fixed Flange Flowmeter Primary