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8.1.6 Pump vibration sensor (PVS 3)
The PVS 3 sensor monitors the vibration level of the pump in
order to protect the pump and the pipe system against damage.
A change in the vibration level is an indication of an abnormal
situation. The reason for this can be a clogged impeller, worn
bearings, a closed discharge valve etc., indicating that a service
inspection should be carried out before the pump or the pipe
system is damaged.
8.1.7 SM 113
The SM 113 is used for collecting and transferring sensor data.
The SM 113 works together with the IO 113 through power line
communication using the Grundfos GENIbus protocol.
The SM 113 collects data from the following devices:
• 3 current sensors, 4-20 mA
• 3 Pt1000 thermal sensors
• 1 PTC thermal sensor
• 1 digital input.
8.1.8 IO 113
The IO 113 forms the interface between a Grundfos sewage and
wastewater pump with analogue and digital sensors and the
pump controller. The most important sensor data are indicated on
the front panel.
One pump can be connected to an IO 113.
Together with the sensors, the IO 113 forms a galvanic separation
between the motor voltage in the pump and the controller
connected.
The IO 113 enables the following functions:
• protecting the pump against overtemperature
• monitoring the sensors for analog measurement of:
– motor temperature
– pump vibrations
– leakages (WIA)
– stator insulation resistance
– bearing temperature
– digital measurement of moisture in motor
• stopping the pump in case of alarm
• remotely monitoring the pump via RS485 communication
(Modbus or GENIbus).
Measurement of insulation resistance
The IO 113 measures the insulation resistance between a stator
winding and earth:
• Resistance above 10 MΩ = ok.
• Resistance between 10 MΩ and 1 MΩ = warning.
• Resistance below 1 MΩ = alarm.
8.2 Frequency converter operation
In principle, all three-phase motors can be connected to a
frequency converter.
However, frequency converter operation will often expose the
motor insulation system to a heavier load and cause the motor to
be more noisy than usual due to eddy currents caused by voltage
peaks.
In addition, large motors driven via a frequency converter will be
loaded by bearing currents.
For frequency converter operation, please observe the following:
• Requirements must be fulfilled.
• Recommendations ought to be fulfilled.
• Consequences should be considered.
8.2.1 Requirements
• The thermal protection of the motor must be connected.
• Peak voltage and dU/dt must be in accordance with the table
below. The values stated are maximum values supplied to the
motor terminals. The cable influence has not been taken into
account. See the frequency converter data sheet regarding the
actual values and the cable influence on the peak voltage and
dU/dt.
• If the pump is an Ex-approved pump, check if the Ex certificate
of the specific pump allows the use of a frequency converter.
• Set the frequency converter U/f ratio according to the motor
data.
• Local regulations/standards must be fulfilled.
8.2.2 Recommendations
Before installing a frequency converter, calculate the lowest
allowable frequency in the installation in order to avoid zero flow.
• Do not reduce the motor speed to less than 25 % of rated
speed.
• Keep the flow velocity above 1 m/sec.
• Let the pump run at rated speed at least once a day in order to
prevent sedimentation in the piping system.
• Do not exceed the frequency indicated on the nameplate as
this may cause motor overload.
• Keep the motor cable as short as possible. The peak voltage
will increase with the length of the motor cable. See data sheet
for the frequency converter used.
• Use input and output filters on the frequency converter.
See data sheet for the frequency converter used.
• Use a screened motor cable if there is a risk that electrical
noise may disturb other electrical equipment. See data sheet
for the frequency converter used.
8.2.3 Consequences
When operating the pump via a frequency converter, please be
aware of these possible consequences:
• The locked-rotor torque will be lower. How much lower will
depend on the frequency converter type. See the installation
and operating instructions for the frequency converter used,
for information on the locked-rotor torque available.
• The working condition of bearings and shaft seal may be
affected. The possible effect will depend on the application.
The actual effect cannot be predicted.
• The acoustic noise level may increase. See the installation
and operating instructions for the frequency converter used,
for advice as to how to reduce the acoustic noise.
8.3 Cable data
Standard H07RN-F
EMC
Maximum repetitive peak
voltage
[V]
Maximum dU/dt U
N
400 V
[V/μ sec.]
850 2000
SE/SL
pump
range
[kW]
Cable type
[mm
2
]
Outer cable diameter
[mm]
Bending
radius
min. max. [cm]
9-30
7 x 4 + 5 x 1.5 21.0 23.0 12.0
7 x 6 + 5 x 1.5 23.8 26.8 13.0
7 x 10 + 5 x 1.5 24.5 27.5 14.0
SE/SL
pump
range
[kW]
Cable type
[mm
2
]
Outer cable diameter
[mm]
Bending
radius
min. max. [cm]
9-30
3 x 6 + 5 x 1 24.5 27.5 14
3 x 10 + 5 x 1 24.7 27.7 14
3 x 16 + 5 x 1 24.9 27.9 14
Cross section of phase
conductor (S) of the
installation
[mm
2
]
Minimum cross section of
earth conductor
[mm
2
]
S ≤ 16 S
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