5.8 Additional protection
5.8.1 Residual-current circuit breakers
WARNING
Electric shock
Death or serious personal injury
‐ This product can cause a DC current in the protective-
earth conductor. If a residual current-operated
protective (RCD) or monitoring (RCM) device is used
for protection in case of direct or indirect contact, only
an RCD or RCM of Type B is allowed on the supply
side of this product.
The residual-current circuit breaker must be marked.
Take into account the total leakage current of all the electrical
equipment in the installation.
This product may cause a direct current in the protective-earth
conductor.
Connection example for three-phase supply
The figure shows an example of a mains-connected three-phase
motor with a main switch, a backup fuse and a residual-current
circuit breaker, type B.
TM069815
Pos.
Description
1 Residual-current circuit breaker, type B
L1 Phase 1
L2 Phase 2
L3 Phase 3
PE Protective earth
5.8.2 Overvoltage and undervoltage protection
Overvoltage and undervoltage may occur in case of unstable power
supply or a faulty installation. The product stops if the voltage falls
outside the permissible voltage range. The product restarts
automatically when the voltage is within the permissible voltage
range. The product requires no additional protection relay.
The product is protected against transients from the power
supply according to EN 61800-3. In areas with high
lightning intensity, we recommend external lightning
protection.
Overvoltage category:
The product is approved for Overvoltage category III rating.
5.8.3 Overload protection
The motor-current protection settings are fixed for each motor
variants. The settings ensure that the motor is protected against
overtemperature in all operating states with regard to supply voltage
and shaft load, including a blocked shaft.
The motors are current controlled and will respond by reducing the
speed if the shaft load increases more than 10 % of the nominal
load.
If the shaft load forces the speed down to minimum speed, the
motor shuts down.
A sudden increase in the motor current caused by a fault where the
peak of the motor current is increased 60 % above nominal will
cause the motor to shut down within 0.5 ms.
The product requires no additional protection.
5.8.4
Overtemperature protection
The motor is thermally protected by a temperature measurement in
the drive. It can handle the lack of airflow over the motor in case the
fan cover is blocked. It also means that the protection has a built-in
memory retention.
The time from start to shutdown due to overtemperature is therefore
always longer when starting at a motor temperature close to the
ambient temperature compared with restarting after a shutdown due
to overtemperature.
5.8.5
Protection against phase unbalance
Phase unbalance on the power supply must be minimised. The
three-phase motor must be connected to a power supply with a
quality corresponding to IEC 60146-1-1, class C. This also ensures
long life of the components.
14
English (US)
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