VEGA VEGACAP 27 - Relay (DPDT) - Manual (Page 19)

19
7 Maintenance and fault rectification
VEGACAP 27 • - Relay (DPDT)
33758-EN-130916
6
7
4
3
CPH
CM
2 MΩ
2 MΩ
2 MΩ
3
2
1
Fig. 21: Check the resistance in the probe
1 Contact 1 (middle pin)
2 Variable capacitor (phase)
3 Capacitor
Measure the resistance values between the following contacts with an
ohmmeter (range MΩ).
Contact 4 against contact 1 (middle pin)
The resistor must be 2 MΩ.
If the resistor is lower, this means moisture in the housing or a fault in
the electrode insulation. A possible reason could be also a non-insu-
lated electrode which is used in a conductive (humid) medium.
If the resistor is higher or if the connection is interrupted, the reason is
mostly a contact error in the adapter plate or a defective resistor due
to strong electrostatic arking.
In both cases, the probe must be repaired in our premises.
Contact 4 against vessel
The electrical connection between contact 4 and metal vessel (not
the mounting boss or probe flange) should good. Measure the resist-
ance value between contact 4 and vessel with an ohmmeter (range
very small).
•
Shortcircuit (0 … 3 Ω) - optimum connection
•
Resistor > 3 Ω - bad connection