Switching Of Inductive Loads - ProMinent DULCOMETER Assembly And Operating Instructions Manual

3.
Large threaded connection (M 20 x 1.5)
Small threaded connection (M 12 x 1.5)
4. Guide the cable into the controller
5. Connect the cable as indicated in the terminal diagram
6. Tighten the clamping nuts of the threaded connections so that they are properly
sealed
7. Plug the controller housing top section on to the controller housing bottom section
8. Manually tighten the housing screws
9. Once again check the seating of the seal. Only if the mounting is correct, is the
degree of protection IP 67 (wall/pipe mounting) or IP 54 (control panel mounting)
achieved
6.3.5

Switching of inductive loads

If you connect an inductive load, i.e. a
consumer which uses a coil (e.g. an
alpha motorised pump), then you
must protect your controller with a
protective circuit. If in doubt, consult
an electrical technician for advice.
The RC member protective circuit is a
simple, but nevertheless very effective,
circuit. This circuit is also referred to as a
snubber or Boucherot member. It is pri‐
marily used to protect switching contacts.
Mounting and installation
When switching off, the connection in
series of a resistor and capacitor means
that the current can fade out in a damped
oscillation.
Also when switching on, the resistor acts
as a current limiter for the capacitor
charging process. The RC member pro‐
tective circuit is highly suited to AC
voltage supplies.
The magnitude of the resistance R of
the RC member is determined according
to the following equation:
R=U/I
L
(U= Voltage divided by the load // I
load current)
Units: R = Ohm; U = Volt; I
C = µF
=
L
= Ampere;
L
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