Electrical Connections; Information On The Correct Operation Of Reed Contacts In Bühler Level Switches - Buhler NS Serie Guía Rápida

NS xx/xx-AM, HD-NS xx-AM
3 Transport and storage
Only transport the product inside the original packaging or a
suitable alternative.
The equipment must be protected from moisture and heat
when not in use. It must be stored in a covered, dry, dust-free
room at room temperature.
4 Setup and connection
DANGER
Electric voltage
Risk of electric shock
a) Always disconnect the unit from the mains before per-
forming work.
b) Secure the equipment from accidental restarting.
c) The equipment may only be installed, maintained and
put into operation by instructed, competent personnel.
d) Always observe the applicable safety regulations for the
operating site.
WARNING
Fluids or gasses discharged at high pressure harmful to
the environment or health
a) Depressurise the system/component prior to installation.
b) Drain the system/component in accordance with envir-
onmental regulations. Wear suitable protective clothing.
4.1 Installation
The float is included in the package (not model NS 25/...AM)
and must be installed prior to installation.
Proceed as follows:
Note: After installing or removing the float, be sure the mag-
net inside the float is above the fluid level. This can easily be
verified with a piece of iron to determine the magnet position
inside the float.
NS 10/... AM NS 64/25 and NS
100/25 AM
Unscrew
the
hexagon
cap at the
bottom of
the riser
top and insert
top
the float
(SK166),
top end
first.
Reattach
the cap
with the
seal at-
tached.
BX200001 ◦ 08/2020
HD-NS ...
Unscrew
the plug
Screw the
from the
dummy
bottom of
flange onto
the riser
the bottom
and insert
end of the
the float,
steel tube
top top end
and insert
first.
the float
After check-
(SK596), top
ing the
end first.
O-ring and
Reattach
back-up
the dummy
ring, screw
flange with
the plug all
seal
the way in
again.
Now attach the side fittings of the level switch to the tank fit-
ting. The holes in all seals must be large enough to prevent
cross-section constriction in the connection fitting. Mounting
to the connections must be tension-free. Therefore tighten all
screws to the same torque.
Every switch has a display. The sight glass is made from
polycarbonate and mounted to the indicator scale. The indic-
ator has a scale and, as the unit, is made from stainless steel.
The solenoid switches (type MKS) are flush mounted to the in-
dicator scale and are variable.

4.2 Electrical connections

DANGER
Electric voltage
Risk of electric shock
When connecting devices, please note the maximum voltages
and currents currents (see technical data) and use the correct
wire cross-sections and circuit breakers.
When selecting the connection lines, also note the maximum
operating temperatures of the devices.
Installation in special areas of application:
If the device will be installed outdoors or in wet areas, the
maximum operating voltage is max. 16 V DC effective or 35 V
DC.
The solenoid switches are available as change-over contact,
single NC contact/NO contact, or as double NC contact/NO
contact. Please refer to the appendix for the terminal config-
uration and technical data of the contacts.
4.3 Information on the correct operation of reed
contacts in Bühler level switches
Based on their construction, reed contacts are very long last-
ing and reliable components. Yet the following should be con-
sidered when using them:
Life of reed switches
The life of reed switches can be up to 10
by high stress and / or incorrect or the absence of protective
circuits when switching inductive, capacitive or lamp loads.
It's therefore important to ensure NEVER to exceed one or sev-
eral of the maximum approved limits, even temporarily, and
to install a contact protective circuit for loads which are not
purely ohmic. Using test lamps when installing the devices is
also prohibited, as these can temporarily allow too much cur-
rent to flow, which can damage the reed contacts. In this case
non-volatile testing equipment should always be used.
9
cycles. This is reduces
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