VEGA Capacitive electrodes EL 4 … 20 mA - Compact - Manual (Page 24)

24
Capacitive electrodes EL 4 … 20 mA - Compact
22652-EN-020809
Electrical connection
A
B
2
1
E2
E1
A2
A1
2
1
A2
A1
E2
E1
V
essel with cathodic corr
osion pr
otection
(Ex) area Zone1 Non (Ex) area
Overvoltage
protection unit
mounted to
oscillator
Oscillator
b)Capacitive electrodes with external
overvoltage protection unit
Screen
Cathodic tank protection
2 … 24 V (object voltage)
CB
2-36
C A P
E32(H)EX
External ground terminal
Internal ground terminal Vessel
Zone 0
Li, Ci of the oscillator with overvoltage
protection unit
Li = 0.27 mH
Ci = 8.5 nF
Control room
optionally:
Overvoltage
protection insert
Signal
condit-
ioning
instru-
ment
or
safety
bar-
rier
Type B62-36G
Li=0.15 mH
Ci=2.5 nF
Overvoltage protection unit
Overvoltage arrester in
metal housing or in plastic
housing must be installed
earth-free
External ground terminal
Internal ground terminal
Cathodic tank protection
2 … 24 V (object voltage)
Insulated cable
min. 4 mm
2
Vessel
Zone 0
Oscillator
Li=0.12 mH
Ci=6 nF
Screen
CAP
E32
(H)Ex
Type
B62-36G
Li=0.15 mH
Ci=2.5 nF
A suitable cable, if necessary with metal cover or
screen, must be used between control room and
overvoltage protection system. Metal cover or
screen - if necessary - should only be connected to
the electrode side of the overvoltage protection
system. The cable must have an outer insulation.
Test voltage of cable A: • 500 V AC
A suitable cable with metal cover, screen or a
suitable cable in a protective metal tube must be
used between overvoltage protection system and
capacitive electrode (metal cover or protective
tube must not be earthed)
Test voltage of cable B: • 1500 V AC
a) Capacitive electrodes with integrated
overvoltage protection unit type CB 2-36
A
B