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Thermal switches (Klixon/
PTC)
Moisture sensor, top
Leakage switch
Leakage switch, stator
housing
Pt1000 in stator winding
Pt1000 in upper bearing
Pt1000 in lower bearing
PVS3 vibration sensor
SM 113
IO 113
IO 113 is available with and without communication. IO 113 with
communication is used when the number of sensors in the pump
require installation of the sensor board (SM 113).
5.1.2 Thermal switches
The thermal protection against overheating is made with
thermistors and with PTC as optional. The three thermal switches
that are hard wired from the pump to the IO 113 unit 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 software alarm in IO 113,
and the alarm relay will open.
5.1.3 PT1000 (stator winding temperature)
It is an analog measurement from 32-356 °F (0-180 °C).
The value from sensor version 1 or Ex. 1 is measured by external
SM 113 (in the control cabinet).
The value from sensor version 2 or Ex. 2 is measured by internal
SM 113 (inside the pump) and transferred to IO 113 through serial
communication.
5.1.4 PT1000 (bearing temperature)
It is an analog measurement from 32-356 °F (0-180 °C). The
value is measured by SM 113 and transferred to IO 113 through
serial communication.
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5.1.5 Moisture and leakage switches
There are two switches placed in an explosion-proof pump, one in
the top cover and one in the stator housing. See fig. 42, sections
C-C and D-D.
There are also two switches in a non-explosion proof pump: a
moisture switch which is placed in the top cover and a leakage
switch which is placed in chamber above the shaft seal. See fig.
42, sections C-C and E-E.
The switches are hard wired from the pump to IO 113. The
switches will open if moisture or leakage is detected and thus
break an electrical circuit. This will generate both a hardware and
a software alarm in IO 113, and the alarm relay will open.
Do not touch the expansion part, that is the
cardboard discs, of the moisture switch with moist or
oily hands.
The moisture and leakage switches must be stored in
an air-tight packaging in order to protect the
expansion part against moisture. The relay is factory-
set to 0.196 in (5 mm) and requires no further setting.
We do not recommend that you exchange a moisture
switch with a leakage switch as it may damage the
pump.
Installation of the leakage switch
Maintenance and service work on explosion-proof
FM
products must be carried out by Grundfos or a
service workshop authorized by Grundfos.
During the installation of the leakage switch (521) on explosion-
proof products an additional safety precautions must be taken.
The reason for this is to avoid the safety distance between the
leakage switch and lower winding heads to be compromised.
Tests has proved that it is possible to reduce the distance by
pulling the wires from the switch during installation. The reason
for the sensor protector (521c) is to ensure that there is no risk of
arching or spark if the minimum safety distance between the
leakage switch and lower winding (48) head is compromised. See
fig. 22.
Fig. 22 Safety distance for leakage switch
48
Safety distance
521c
521
15
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