Grundfos SE1 50 Instrucciones De Instalación Y Funcionamiento página 19

8.4 Thermal switch, PT 1000 and thermistor (PTC)
All SE1 and SEV pumps have thermal protection incorporated in
the stator windings.
Pumps without sensor
Pumps without sensor have a thermal switch or a PTC thermistor.
Via the pump controller safety circuit, the thermal switch will stop
the pump by breaking the circuit in case of overtemperature
(approx. 150 °C). The thermal switch will reclose 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 sensor
Pumps with sensor have either a thermal switch and a Pt1000
sensor or a PTC thermistor in the windings, depending on the
installation site.
Via the pump controller safety circuit, the thermal switch or the
thermistor will stop the pump by breaking the circuit in case of
overtemperature (approx. 150 °C). The thermal switch or the
thermistor will reclose 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 via the controller. Pumps from
4 kW and up sold in Australia/New Zealand are fitted with a PTC
thermistor.
Explosion-proof pumps
Warning
The thermal protection of explosion-proof pumps
must not restart the pump automatically.
This ensures protection against overtemperature in
potentially explosive environments. In pumps with
sensor this is done by removing the short-circuit
between terminals R1 and R2 in the IO 111. See
Electrical data in the IO 111 installation and operating
instructions.
Warning
The separate motor-protective circuit breaker/control
box must not be installed in potentially explosive
environments.
8.5 WIO sensor
The WIO sensor measures the water content in the oil and
converts the value into an analog current signal. The two sensor
conductors are for power supply as well as for carrying the signal
to the IO 111 module. 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). The sensor is fitted in a stainless steel tube for
mechanical protection.
Fig. 13 WIO sensor
8.5.1 Fitting the WIO sensor
Fit the sensor next to one of the shaft seal openings. See fig. 13.
The sensor must be tilted into the motor's direction of rotation to
ensure that oil is led into the sensor. Make sure that the sensor is
submerged in the oil.
8.5.2 Technical data
Input voltage: 12-24 VDC
Output current: 3.5 - 22 mA
Power input: 0.6 W
Ambient temperature: 0 to 70 °C
See also the installation and operating instructions for IO 111 at
www.grundfos.com.
8.6 Moisture switch
The moisture switch is positioned in the bottom of the motor.
If there is moisture in the motor, the switch will break the circuit
and send a signal to the IO 111.
The moisture switch is non-reversing and must be replaced after
use.
The moisture switch is connected in series with the thermal
switch and connected to the monitoring cable, and it must be
connected to the safety circuit of the separate pump controller.
See section 8. Electrical connection.
The motor-protective circuit breaker of the pump
controller must include a circuit which automatically
Caution
disconnects the power supply in case the protective
circuit for the pump is opened.
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