Pump Controllers; Thermal Switches - Grundfos SEG Instrucciones De Instalación Y Mantenimiento

8.3 Pump controllers

The following LC and LCD pump controllers are
available:
LC controllers are for one-pump-installations and
LCD controllers are for two-pump-installations.
• LC 107 and LCD 107 with air bells.
• LC 108 and LCD 108 with float switches.
• LC 110 and LCD 110 with electrodes.
In the following description, "level switches" can be
air bells, float switches or electrodes, depending on
the pump controller selected.
Controllers for single-phase pumps incorporate
capacitors.
LC: The controller is fitted with two or three level
switches: One for start and the other for stop of
pump. The third level switch, which is optional, is for
high-level alarm.
LCD: The controller is fitted with three or four level
switches: One for common stop and two for start of
the pumps. The fourth level switch, which is optional,
is for high-level alarm.
When installing the level switches, the following
points should be observed:
• To prevent air intake and vibrations, install the
stop level switch in such a way that the pump is
stopped before the liquid level is lowered below
the middle of the motor housing.
• The start level switch should be installed in such
a way that the pump is started at the required
level; however, the pump must always be started
before the liquid level reaches the bottom inlet
pipe to the pit.
• The high-level alarm switch, if installed, should
always be installed about 10 cm above the start
level switch; however, the alarm must always be
given before the liquid level reaches the inlet pipe
to the pit.
For further settings, see the installation and
operating instructions for the pump controller
selected.
Warning
The pump must not run dry.
An additional level switch must be
installed to ensure that the pump is
stopped in case the stop level switch is
not operating.
Stop the pump when the liquid level
reaches the upper edge of the clamp on
the pump.
Float switches used in explosive
environments must be approved for
this application. They must be
connected to the Grundfos LC, LCD 108
LC 107, LC 110 pump controller via the
intrinsically safe LC-Ex4 barrier to
ensure a safe circuit.

8.4 Thermal switches

All SEG pumps have two sets of thermal switches
incorporated in the stator windings.
Thermal switch, circuit 1 (T1-T3), breaks the circuit
at a winding temperature of approx. 150 °C.
This thermal switch must be connected
Note
for all pumps.
Thermal switch, circuit 2 (T1-T2), breaks the circuit
at a winding temperature of approx. 170 °C (three-
phase pumps) or 160 °C (single-phase pumps).
Warning
After thermal cutout, explosion-proof
pumps must be restarted manually.
The thermal switch (circuit 2) must be
connected for manual restarting of
these pumps.
The maximum operating current of the thermal
switches is 0.5 A at 500 VAC and cos φ 0.6.
The switches must be able to break a coil in the
supply circuit.
In the case of standard pumps, both thermal
switches can (when closing the circuit after cooling)
generate automatic restarting of the pump via the
controller.
Warning
The separate motor-protective circuit
breaker/control box must not be
installed in potentially explosive
environments.
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