6.2.2 Three-phase supply voltage
•
3 x 440-480 V - 10 %/+ 10 %, 60 Hz, PE.
In order to avoid loose connections, ensure that
the terminal block for L1, L2 and L3 is pressed
Caution
home in its socket when the supply cable has
been connected.
Corner grounding is not allowed for supply
Note
Note
voltages above 3 x 480 V, 60 Hz.
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 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.
For maximum backup fuse, see section 21.1 Supply voltage.
L1
ELCB
L2
(GFCI)
L3
PE
Example of a mains-connected motor with mains
Fig. 6
switch, backup fuses and additional protection
Mains connection, three-phase motors
Fig. 7
8
6.3 Additional protection
6.3.1 Single-phase motors
If the motor is connected to an electric installation where an earth
leakage circuit breaker (ELCB) or ground fault circuit interrupter
(GFCI) is used as additional protection, this circuit breaker or
interrupter must be marked with the following symbol:
When an earth leakage circuit breaker or ground
fault circuit interrupter is selected, the total
Note
Note
leakage current of all the electrical equipment in
the installation must be taken into account.
The leakage current of the motor can be found in section
20.2 Leakage current.
6.3.2 Three-phase motors
If the motor is connected to an electric installation where an earth
leakage circuit breaker (ELCB) or ground fault circuit interrupter
L1
(GFCI) is used as additional protection, this circuit breaker or
interrupter must be of the following type:
L2
•
It must be suitable for handling leakage currents and cutting-in
L3
with short pulse-shaped leakage.
•
It must trip out when alternating fault currents and fault
currents with DC content, i.e. pulsating DC and smooth DC
fault currents, occur.
For these motors an earth leakage circuit breaker or ground fault
circuit interrupter, type B, must be used.
This circuit breaker or interrupter must be marked with the
following symbols:
When an earth leakage circuit breaker or ground
fault circuit interrupter is selected, the total
Note
Note
leakage current of all the electrical equipment in
the installation must be taken into account.
The leakage current of the motor can be found in section
21.2 Leakage current.
Protection against phase unbalance
The motor 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.
ELCB
(GFCI)
ELCB
(GFCI)