Kobold NBK-R series, Operating Instructions Manual

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NBK-R...
page 4 NBK-R... K04/0617
4.1 Electrical limit switch
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For standard applications NBK-R/NBK-RM: Bistable changeover contact fitted in
a polycarbonate housing with 3m connection cable
-
For high temperature applications NBK-RT200/-RT400: Bistable changeover
contact fitted in an aluminium die cast housing with terminal connectors.
-
For ATEX applications NBK-RA: Bistable changeover contact as an
encapsulated proximity switch fitted in metallic cast housing with 3 m connection
cable.
ATEX-marking for contact NBK-RA (encapsulated version):
II 2G Ex mb IIC T6 / T5 Gb
II 2D Ex mb IIIC IP67 T 105 °C Db

Use the contacts appropriate and as intended.

Make sure that only accessories are used in hazardous areas that meet
all the requirements of the European directives and national legislation.
The contacts NBK-RA with ATEX approval meet the requirements of category
2 GD. The proximity switches with ATEX approval are used in the following
zones:

2G in zone 1

3G in zone 2

2D in zone 21

3D in zone 22
5. Operating Principle
Kobold Bypass Limit Transmitter are used for the monitoring of limit values in
tanks or vessels.
They are firmly attached with mounting plates and ribbon clamps to the Bypass
Level Indicator, model NBK, and can be moved to any position on the bypass-
tube within the measuring length.
The reed-contacts in the limit switches react bistable and they are switched by
the magnetic float inside the NBK tube as passing by.
One or more limit switches can be mounted on the bypass.