English (GB)
25
8.1.4 Thermal bearing protection
Standard pumps incorporate one Pt100 sensor for
analog measurement of the temperature of the lower
bearing and one Pt100 sensor for the upper bearing.
The sensors are connected in separate circuits in the
power or control cables. See section
The sensors must be connected to a Pt100 relay in
the control cabinet, preferably a Grundfos SM 113 or
IO 113.
The resistance of the sensors varies with the
temperature. The table below shows the
approximate values.
The following temperature limits are defined:
•
90 °C: alarm for bearing temperature
•
130 °C: pump stop caused by high bearing
temperature.
Check the following when you have installed the
pump:
1. Using a multimeter, check whether the resistance
at 20 °C is approximately 107.8
Ω
.
2. Carry out similar measurements at COM1, B/S-L
and B/S-H of SM 113 and of the power cables.
See section
.
– In case SM 113 is installed inside the pump the
measurement must be done from SM 113
wirings in the junction box. See fig.
appendix.
– In case SM 113 is installed outside the pump
the measurement must be done from SM 113
wirings or end of the control cables. See fig.
in the appendix.
Connect the Pt100 sensor to a recording device
during pump check.
8.1.5 Water-in-oil sensor (WIO) (only KPL and
KWM)
The WIO sensor measures the water content in the
oil chamber and converts the value into an analog
current signal. The two sensor wires are for power
supply and for carrying the signal to the measuring
device or controller. 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 the oil level is low (alarm). The sensor is fitted in
a stainless steel tube for mechanical protection.
The WIO sensor can be used together with Grundfos
IO 113 or SM 113, but it can also be used together
with other controllers with 4-20 mA inputs.
Together with IO 113, the WIO sensor filters the
signal and provides an easy readout of the actual
value. Furthermore, it is possible to set a user-
defined warning limit and calibrate IO 113 and the
sensor to the motor oil.
The WIO sensor works in the following way:
Sensor signals
Technical data
[
Ω
]
[°C]
100
0
138.5
100
107.8
20
Do not use a megohmmeter to test this
alarm due to the low resistance of the
sensor circuits.
Do not use Shell Ondina 420X motor oil in
case a WIO sensor is in use.
Lack of oil may cause overheating and
damage of the mechanical shaft seals. The
WIO sensor in the oil chamber trips the
alarm if the oil quality is poor or there is
not enough oil in the oil chamber.
The WIO sensor signal is only valid when
oil and water are mixed, that is when the
pump is running.
4-20 mA =
0-20 % water in the oil
Accuracy is better than 2 %
22 mA
=
Warning:
The water content is above 20 %
3.5 mA
=
Alarm:
There is air in the oil chamber
Input voltage:
12-24 VDC
Output current:
3.4 - 22 mA
Power input:
0.6 W
Ambient temperature:
0 to 70 °C
