Frequency Converter Operation; Before Starting The Bmpx - Grundfos BMPX Serie Instrucciones De Instalación Y Funcionamiento

9.2.1 Frequency converter operation

Three-phase Grundfos MS motors can be connected to a
frequency converter.
If an MS motor with temperature transmitter is
connected to a frequency converter, a fuse
incorporated in the transmitter will melt and the
transmitter will be inactive. The transmitter
Caution
cannot be reactivated. This means that the motor
will operate like a motor without a temperature
transmitter.
If a temperature transmitter is required, a Pt100 sensor for fitting
to the motor can be ordered from Grundfos.
During frequency converter operation, it is not
advisable to run the motor at a frequency higher
than the rated frequency (50 or 60 Hz).
In connection with pump operation, it is
Caution
important never to reduce the frequency (and
consequently the speed) to such a level that the
necessary flow of cooling liquid past the motor is
no longer ensured.
The permissible frequency ranges are 30-50 Hz and 30-60 Hz,
respectively.
During starting, the maximum acceleration time from 0 to 30 Hz is
1 second.
During stopping, the maximum deceleration time from 30 to 0 Hz
is 1 second.
Depending on the frequency converter type, it may expose the
motor to detrimental voltage peaks.
The above disturbance can be abated by installing an RC filter
between the frequency converter and the motor.
Possible increased acoustic noise from the motor can be abated
by installing an LC filter which will also eliminate voltage peaks
from the frequency converter.
For further details, please contact your frequency converter
supplier or Grundfos.
9.2.2 Motor protection
See section 9.1.1 Motor protection.
The control circuit must always be made in such a way that all
pumps of the BMPX system are stopped if one pump fails.
9.2.3 Setting of motor starter
For cold motors, the tripping time for the motor starter must be
less than 10 seconds (Class 10) at 5 times the rated current
(I /I ) of the motor. See motor nameplate.
1/1 SFA
If this requirement is not met, the motor warranty
Note
will be invalidated.
To ensure optimum protection of the motor, the starter overload
unit should be set in accordance with the following guidelines:
1. Set the starter overload to the rated current (I
motor.
2. Start the BM hp circulation pump and let it run for half an hour
at normal performance. See section 9.2 BM hp circulation
pump.
3. Slowly grade down the scale indicator until the motor trip point
is reached.
4. Increase the overload setting by 5 %, but not higher than the
rated current (I /I ) of the motor.
1/1 SFA
For motors wound for star-delta starting, the starter overload unit
should be set as above, but the maximum setting should be as
follows:
Starter overload setting = rated current (I
The maximum permissible run-up changeover time for star-delta
starting is 2 seconds.
8
/I ) of the
1/1 SFA
/I ) x 0.58.
1/1 SFA

10. Before starting the BMPX

Check the following:
• Electricity supply in accordance with nameplate.
• Pipework according to the diagram, fig. 12.
• Functionality of the solenoid valve (BM hp circulation pump
only).
• Functionality of the low-pressure switch on the inlet side of the
BMP hp feed pump.
See set value in the installation and operating instructions for
BMP pumps.
In addition, flush all pipes to remove all impurities before
connecting the units.
HP
CV1
V5
V2
S1
CV1
P3
P4
FM1
LP
V1
P1 P2
Fig. 12 Piping and instrumentation diagram
Pos. Description
P1 Sea-water feed pump
P2 Cleaning/flush pump
P3 BMP hp feed pump
P4 BM hp circulation pump with variable-frequency drive
V1 Three-way valve for feed water and cleaning
V2 Control valve for controlling pressure and flow
V3 Low-pressure reject-water valve
V4 Solenoid valve
V5 Control valve for controlling pressure and flow
V6 Cleaning/flush valve
CV1 Non-return valve
FM1-3 Flowmeter for balancing the system
X1 X-Changer
HP High-pressure switch
LP Low-pressure switch
S1 Pressure relief valve
Semi-permeable membrane
V4
FM3
V6
FM2 X1
V3