English (GB)
17
To find out whether the pump is fitted with a thermal
switch or a PTC thermistor, measure the motor
winding resistance. See table below.
Protection and control functions
Level controllers
To prevent air intake, dry running and vibrations,
install the stop level switch so the pump is stopped
before the liquid level falls below the upper edge of
the pump’s clamp.
Fig. 10
Start and stop levels
Switches and sensors
Explosion-proof pumps are assembled with a
WIO sensor optionally. The sensor measures the
water content from 0 to 20 %. It also sends a signal if
the water content is outside the normal range
(warning), or if there is air in the oil chamber (alarm).
Thermal switch, Pt1000 and PTC thermistor
All SL1 and SLV pumps have thermal protection
incorporated in the stator windings.
Pumps without sensor
Pumps without sensor have a thermal switch or a
PTC thermistor. Through the pump controller safety
circuit, the thermal switch will stop the pump by
breaking the circuit in case of overtemperature
(approximately 150 °C). The thermal switch will close
the circuit after cooling. For pumps equipped with a
PTC thermistor, connect the thermistor to either the
PTC relay or the I/O module to break the circuit at
150 °C.
The maximum operating current of the thermal
switch is 0.5 A at 500 VAC and cos
φ
0.6. The switch
must be able to break a coil in the supply circuit.
Pumps with WIO sensor
Pumps with WIO sensor have either a thermal switch
and a Pt1000 sensor or a PTC thermistor in the
windings, depending on the installation site.
Through the pump controller safety circuit, the
thermal switch or the thermistor will stop the pump
by breaking the circuit in case of overtemperature
(approximately 150 °C). The thermal switch or the
thermistor will close the circuit after cooling.
The maximum operating current of both the Pt1000
and the thermistor is 1 mA at 24 VDC.
Non-explosion-proof pumps
When closing the circuit after cooling, the thermal
protection can restart the pump automatically
through the controller. Pumps from 4 kW and up sold
in Australia and New Zealand are fitted with a PTC
thermistor.
Without
cable
With 10 m
cable
With 15 m
cable
Thermal
switch
< 50 m
Ω
< 320 m
Ω
< 390 m
Ω
PTC
thermistor
> 100 m
Ω
> 370 m
Ω
> 440 m
Ω
TM
04
26
5
4
28
08
The pump must not run dry. Dry running
may cause ignition hazard.
Install an independent secondary level
switch to the same level to ensure that the
pump is stopped in case the primary stop
level switch is not working.
Stop level switches must be set to Stop S1
or Stop S3 levels, depending on operation.
Start
Stop S1
operation
Alarm
Min. 10 cm
Stop S3
operation
