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5.3.2 Three-phase supply voltage
Three-phase motors are available for the voltages below:
•
3 x 380-500 V - 10 %/+ 10 %, 50/60 Hz, PE
•
3 x 200-240 V - 10 %/+ 10 %, 50/60 Hz, PE.
Check that the supply voltage and frequency correspond to the
values stated on the nameplate.
The wires in the motor terminal box must be as short as possible.
Excepted from this is the separated ground (earth) conductor
which must be so long that it is the last one to be disconnected in
case the cable is inadvertently pulled out of the cable entry.
In order to avoid loose connections, ensure that the terminal
block for L1, L2 and L3 is pressed home in its socket when the
supply cable has been connected.
For maximum backup fuse, see section
If you want to supply the motor through an IT
network, make sure that you have a suitable motor
variant. If you are in doubt, contact Grundfos.
Only the following motors can be supplied through an IT network:
•
Motors with speed of 1450-2000/2200 rpm and up to 2.0 HP
(1.5 kW)
•
Motors with speed of 2900-4000 rpm or 4000-5900 rpm and up
to 3 HP (2.2 kW).
Corner grounding is not allowed for supply voltages
above 3 x 480 V, 50/60 Hz.
GFCI, type B
L1
L2
L3
PE
Fig. 6
Example of a mains-connected motor with mains
switch, backup fuses and additional protection
Fig. 7
Mains connection, three-phase motors
8
25.1 Supply
voltage.
L1
L2
L3
5.4 Additional protection
DANGER
Electric shock
Death or serious personal injury
- Only use residual-current circuit breakers (ELCB,
GFCI, RCD) of type B.
The residual-current circuit breaker must be marked with the
following symbol:
The total leakage current of all the electrical equipment in the
installation must be taken into account. You find the leakage
current of the motor in sections
25.2 Leakage current,
AC.
This product can cause a direct current in the protective earth
conductor.
Overvoltage and undervoltage protection
Overvoltage and undervoltage may occur in case of unstable
power supply or a faulty installation. The motor is stopped if the
voltage falls outside the permissible voltage range. The motor
restarts automatically when the voltage is again within the
permissible voltage range. Therefore, no additional protection
relay is required.
The motor is protected against transients from the
power supply according to EN 61800-3. In areas with
high lightning intensity, we recommend external
lightning protection.
Overload protection
If the upper load limit is exceeded, the motor automatically
compensates for this by reducing the speed and stops if the
overload condition persists.
The motor remains stopped for a set period. After this period, the
motor automatically attempts to restart. The overload protection
prevents damage to the motor. Consequently, no additional motor
protection is required.
Overtemperature protection
The electronic unit has a built-in temperature sensor as an
additional protection. When the temperature rises above a certain
level, the motor automatically compensates for this by reducing
the speed and stops if the temperature keeps rising. The motor
remains stopped for a set period. After this period, the motor
automatically attempts to restart.
Protection against phase unbalance
Three-phase motors must be connected to a power supply with a
quality corresponding to IEC 60146-1-1, class C, to ensure
correct motor operation at phase unbalance. This also ensures
long life of the components.
and
24.2 Leakage current
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