Permanent Magnet Synchronous Motor; Thermal Overload And Short-Circuit Protection; Thermal Overload Protection Of The Drive And The Input And Motor Cables - ABB ACS800-07-0610-3 Hardware Manual

If voltage is raised by the drive (this is a parameter selectable function for special applications only),
select the motor insulation system according to the increased intermediate circuit DC voltage level,
especially in the 500 V supply voltage range.
Note 8: Calculating the rise time and the peak line-to-line voltage
The peak line-to-line voltage at the motor terminals generated by the drive as well as the voltage rise
time depend on the cable length. The requirements for the motor insulation system given in the table
are "worst case" requirements covering installations with 30-metre and longer cables. The rise time can
be calculated as follows:
the values of the graph by the supply voltage (U
braking, the Û
3.0
2.5
2.0
1.5
1.0
0.5
0.0
100
Note 9: Sine filters
Sine filters protect the motor insulation system. Therefore, a du/dt filter can be replaced with a sine
filter. The peak phase-to-phase voltage with a sine filter is approximately 1.5 × U

Permanent magnet synchronous motor

Only one permanent magnet motor can be connected to the inverter output.
It is recommended to install a safety switch between a permanent magnet
synchronous motor and the motor cable. The switch is needed to isolate the motor
during any maintenance work on the drive.

Thermal overload and short-circuit protection

Thermal overload protection of the drive and the input and motor cables

The drive protects itself and the input and motor cables against thermal overload
when the cables are dimensioned according to the nominal current of the drive. No
additional thermal protection devices are needed.
WARNING! If the drive is connected to multiple motors, a separate thermal overload
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t = 0.8 · Û
and du/dt values are approximately 20% higher.
LL
Û /U
LL N
du/dt
------------ - (1/μs)
U
N
200 300
Cable length (m)
With du/dt Filter
/(du/dt). Read Û and du/dt from the diagrams below. Multiply
LL LL
). In case of drives with an IGBT supply unit or resistor
N
5.5
5.0
du/dt
------------ - (1/μs)
U
4.5
N
4.0
3.5
3.0
2.5
2.0
1.5
1.0
100
Without du/dt Filter
Û /U
LL N
200 300
Cable length (m)
.
N
Planning the electrical installation
59