English (GB)
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7.5.1 Thermal switches
The thermal protection against overheating is achieved with
bimetallic switches as standard or thermistors as optional.
The three thermal switches that are hardwired from the pump to
IO 113, or similar controller, will open if the stator windings
become too hot. The thermal switches are of the reversible type
and will close again when the motor has cooled down.
This generates both a hardware and a software alarm in IO 113,
and the alarm relay will open.
7.5.2 Moisture switches
Non-explosion-proof pumps have one moisture switch which is
fitted in the chamber below the motor top cover.
Ranges 50-58 and 70 explosion-proof pumps have two moisture
switches, one below the motor top cover and one in the stator
housing in the bottom of the motor.
Range 62 pumps have both moisture switches placed below the
motor top cover.
The moisture switches are hardwired from the pump to IO 113, or
similar controller. They will open if moisture is detected and thus
break an electric circuit. This will generate both a hardware and a
software alarm in IO 113, and the alarm relay will open.
7.5.3 Pt100, optional
The Pt100 temperature sensor is available as an accessory or as
an FPV (Factory Product Variant) option.
The Pt100 sensor is primarily used for the monitoring of the
bearing temperature, but it can also be used in the stator.
If the pump does not have an SM 113, hardwire the Pt100 sensor
out of the pump and connect it to an external unit. See fig.
. If
the pump has an SM 113, connect the Pt100 sensor to SM 113.
No external unit is required.
Maximum alarm temperatures can be seen in table below:
7.5.4 Thermistors, optional
Thermistors are available as an accessory or as an FPV option.
The thermistors can be used as motor protection devices to
monitor stator temperature instead of thermal switches and must
be connected to the thermistor relay in the control cabinet.
7.5.5 WIO sensor, optional
The WIO sensor is available as an accessory for all standard
(non-explosion-proof) pumps with motor sizes of 5.5 to 155 kW. It
can be factory fitted or installed after the pump has been started
up.
The oil chamber is filled with oil acting as lubricant and coolant for
both mechanical seals. The WIO sensor measures the water
content in the oil chamber:
• 0-20 % water in the oil causes no reaction.
• Water content outside measuring range causes a warning.
• Oil level too low causes an alarm.
The sensor consists of a plate capacitor which is immersed in the
oil and measures the electronic circuit, emitting a 4-20 mA
proportional current signal.
More detailed information can be found in the installation and
operation instructions, 96591899, or in Grundfos Product Center
at www.grundfos.com.
Install an automatic circuit
breaker, which disconnects the
power supply in case the thermal
switches or the moisture switches
are not operating.
For range 50 and 54 explosion-
proof pumps, the temperature
sensor is only available for
monitoring the lower bearing
temperature.
Pump
range
Alarm temperatures
Winding
temperatur
e
[°C]
Upper
bearing
[°C]
Lower
bearing
[°C]
50-54
150
130
90
58-70
150
120
100
In case of overheating caused by
wear, lack of lubricant etc., the
Pt100 sensor trips an alarm and
disconnects the power supply at a
preset temperature.
The maximum acceptable alarm
temperature can be seen in the
table above.
The WIO sensor is only available
for the explosion-proof pumps in
the ranges 58, 62 and 70. The
sensor must be fitted from
factory.
Lack of oil may cause
overheating and damage to the
mechanical shaft seals. The WIO
sensor in the oil chamber will trip
the alarm if the oil quality is poor
or there is not enough oil in the oil
chamber.
Do not use Shell Ondina X420 oil
in pump fitted with WIO sensor.
