NBK-19
NBK-19 K03/0322
Seite 9
8. Operation
8.1 Operation of the level indicator
The screw connections should be checked and tightened where necessary.
Fill the container and switch on the electrical control system, where used.
The liquid, which now enters the tank, raises the tank float and lowers the bypass float,
which then shows the level of liquid in the tank in the bypass tube and on the scale or
the roller indicator where present.
8.2 Operation of the electrical limit contact
Function of the limit contacts
All contacts have three terminals (black, blue and brown). The black wire represents
the common terminal for both switches (N/C and N/O).
So that the switch function corresponds to the wiring diagram / the table below, the
float must pass the contact once in both directions.
This point is frequently neglected where an alarm light is connected directly, and it is
assumed that the contact is defective.
The contact is ready for operation once the contact has been passed and does not
require any maintenance.
Black / blue
Black / brown
Float above
open
electrically conducting
Float below
electrically conducting open
Hysteresis
The difference between the points at which the contact switches
on and off is known as the hysteresis. Factory tuning of the float
magnet contact strength gives a hysteresis of about 15 mm of
vertical travel of the float.
