28
MagCheck
5.5 Coil
insulation
Coil insulation is a vital parameter for accurate function of a magnetic flowmeter. Causes for poor
insulation may be found in wet or defective field current cable, wet or dirty terminals and connectors
or liquid entrained in the meter body. What to do if result "Coil insulation" is "NOT OK":
•
Check converter field current cable connectors,
flowhead terminals and PC-board. Clean, dry?
•
Bottom side of PC-board and connector in flowhead
connection box. Clean and dry thoroughly!
Disconnect field current wires at flowhead terminals
7,8.
•
Do not disconnect cable shield terminals 1, GND
•
Make sure that open cable ends are clean, dry and do
not contact each other or any flow meter part.
•
Repeat verification. Does MagCheck indicate
insulation > 10 MOhm? Now?
→
NOT OK?
Field current cable
defective,
low insulation
Exchange!
↓
OK?
•
Cable is ok. Investigate flowhead connection box:
Terminals and PC-board clean, dry?
(also Bottom side and connector). Clean and dry
thoroughly! Re-assemble the cable connections.
•
Disconnect all cables to converter
•
Do an insulation test (
≤
100 VDC) on flowhead
terminals 7 or 8 to 1 or GND > 10 MOhm?
→
NOT OK?
Contact KROHNE
↓
OK?
Field coil insulation OK
5.6 Limitations
of
accuracy
statement
MagCheck is verifying all vital electrical data of the flowmeter and converter. The verification result
does not include factors as: deposits in flowtube, installation not according to installation rules,
gases in the liquid.
