Electrical Connection; Frequency Converter Operation; Operating Conditions - Grundfos LSV Montage- Und Betriebsanleitung

3.3 Electrical connection

The electrical connections must be carried out by an
authorised electrician in accordance with local
regulations.
DANGER
Electric shock
Death or serious personal injury
‐
Before you remove the terminal box
cover and before you remove or
dismantle the pump, make sure that
the power supply has been switched
off and that it cannot be accidentally
switched on.
The operating voltage and frequency are marked on
the motor nameplate.
Make sure that the motor is suitable for the power
supply of the installation site.
Carry out the electrical connections as shown on the
motor nameplate or in the wiring diagram on the back
of the terminal box cover.
For further information, contact the motor supplier.
DANGER
Electric shock
Death or serious personal injury
‐
Whenever you use powered equipment
in explosive surroundings, observe the
rules and regulations generally or
specifically imposed by the relevant
responsible authorities or trade
organisations.

3.3.1 Frequency converter operation

You can connect all three-phase motors to a
frequency converter.
However, frequency converter operation often
exposes the motor insulation system to a heavier load
and causes the motor to be more noisy than usual
due to eddy currents caused by voltage peaks.
If in doubt whether the supplied motor can
handle frequency converter operation,
contact the motor supplier.
In addition, large motors driven via a frequency
converter will be loaded by bearing currents.
When the pump is operated via a frequency
converter, check the following operating conditions:
Operating
Action
conditions
2-, 4- and 6-pole
Ensure that the non-drive-end
motors, frame
motor bearing is electrically
size 225 and
isolated.
larger
Fit a dU/dt filter between the
Noise-critical motor and the frequency
applications converter. It reduces the voltage
peaks and thus the noise.
Particularly
noise-critical Fit a sinusoidal filter.
applications
Fit a cable that meets the
specifications laid down by the
frequency converter supplier.
Cable length
The length of the cable between
the motor and frequency
converter affects the motor load.
Make sure that the motor is
Supply voltage
suitable for frequency converter
up to 500 V
operation.
• Fit a dU/dt filter. It reduces
the voltage peaks and thus
Supply voltage
the noise.
between 500 V
and 690 V
• Or make sure that the motor
has reinforced insulation.
• Fit a dU/dt filter.
Supply voltage of
690 V and
• Make sure that the motor has
upwards
reinforced insulation.
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