Separate Level Controllers; Electrical Connection; Motor Protection - Grundfos APG Serie Montage- Und Betriebsanleitung

6.4 Separate level controllers

Three-phase APG pumps without control box or level
switch can be supplied with a separate level
controller with level switches: type LC for one-pump
installations and type LCD for two-pump
installations.
The LC controller is fitted with two or three level
switches. The third level switch, which is optional, is
for high-level alarm.
The LCD controller is fitted with three or four level
switches: one for common stop and two for start of
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 falls to below the
top of the pump housing.
• Install the start level switch 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 in the
pit.
• If installed, the high-level alarm switch should
always be placed about 10 cm above the start
level switch. However, alarm must always be
given before the liquid level reaches the pit inlet
pipe.
To ensure correct operation of the pump,
make sure to adjust and fit the level sensor
Note
correctly. Carry out a test run of the pump
after each adjustment of the level sensor.
8

7. Electrical connection

The electrical connection of the pump should be
carried out in accordance with local regulations.
The operating voltage and frequency are stated on
the nameplate. Voltage tolerance: ± 10 % of the
voltage stated on the nameplate. Make sure that the
motor is suitable for the power supply available at
the installation site.

7.1 Motor protection

All pumps are supplied with 10 metres of cable and a
free cable end.
All single-phase pumps supplied without control box
must be connected to a separate control box with
motor starter and run capacitor. Furthermore, the
pumps must be connected to a starting capacitor.
For capacitor sizes, see the table below.
60 Hz
Starting
capacitor
Pump type
[μF]
APG.50.12.1 50
APG.50.18.1 80
APG.50.30.1 150
APG.50.33.1 150
APG.50.12.1 has a thermal switch built into the motor
windings. The thermal switch cuts out the motor in
case of overtemperature and cuts it in again
automatically after cooling.
All 3-phase pumps supplied without control box must
be connected to a separate motor starter.
APG pumps of 4.8 kW and up are prepared for star-
delta starting, i.e. both ends of the motor windings
are accessible through the motor cable. See fig. 2.
• T1 and T3 are connected to the standard set of
temperature sensors.
• T1 and T2 are connected to the extra set of
temperature sensors in explosion-proof pumps.
• S1 and S2 are connected to a moisture sensor in
the oil chamber.
Run
capacitor
[V] [μF] [V]
1 x 230 25 1 x 450
1 x 230 40 1 x 450
1 x 230 60 1 x 450
1 x 230 60 1 x 450