Permanent Magnet Motor - ABB ACS800-04 Hardware Manual

44 Planning the electrical installation
Resistor braking of the drive
Note 7:
When the drive is in braking mode for a large part of its operation time, the
intermediate circuit DC voltage of the drive increases, the effect being similar to
increasing the supply voltage by up to 20 percent. Consider the voltage increase
when you determine the motor insulation requirement.
Example: Motor insulation requirement for a 400 V application must be selected as if
the drive were supplied with 480 V.
Calculating the rise time and the peak line-to-line voltage
Note 8:
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-meter and longer cables. The rise time can be calculated as
Û
follows: t = 0.8 ·
Multiply the values of the graph by the supply voltage (
IGBT supply unit or resistor braking, the
higher.
3.0
2.5
2.0
1.5
1.0
0.5
0.0
100
With du/dt Filter
Note 9: Sine filters protect the motor insulation system. Therefore, d
be replaced with a sine filter. The peak phase-to-phase voltage with the sine filter is
approximately 1.5 ×
Note 10: Common mode filter is available as an option (+E208) or as a separate kit
(one box with three rings for one cable).

Permanent magnet motor

Only one permanent magnet motor can be connected to the inverter output.
ABB recommends a safety switch between the permanent magnet motor and the
drive output. The switch isolates the motor during maintenance work.
u t Û
/(d /d ). Read
LL
Û /U
LL N
du/dt
------------ - (1/s)
U
N
200 300
Cable length (m)
U
.
N
u t
and d /d from the diagrams below.
LL
U
Û u t
and d /d values are approximately 20%
LL
5.5
5.0
du/dt
------------ - (1/s)
U
4.5
N
4.0
3.5
3.0
2.5
2.0
1.5
1.0
100
Without du/dt Filter
). In case of drives with an
N
Û /U
LL N
200 300
Cable length (m)
u t
/d filter can