User guide

Safety
information
Product
information
Mechanical
installation
Electrical
installation
Getting
started
Basic
parameters
Running the
motor
Optimization NV Media Card
Advanced
parameters
Technical
data
Diagnostics
UL listing
information
Unidrive M100 User Guide 37
Issue Number: 1
Table 4-10 Maximum motor cable lengths (200 V drives)
Table 4-11 Maximum motor cable lengths (400 V drives)
4.4.2 High-capacitance / reduced diameter cables
The maximum cable length is reduced from that shown in Table 4-9,
Table 4-10 and Table 4-11, if high capacitance or reduced diameter
motor cables are used.
Most cables have an insulating jacket between the cores and the armor
or shield; these cables have a low capacitance and are recommended.
Cables that do not have an insulating jacket tend to have high
capacitance; if a cable of this type is used, the maximum cable length is
half that quoted in the tables, (Figure 4-6 shows how to identify the two
types).
Figure 4-6 Cable construction influencing the capacitance
The cable used for Table 4-9, Table 4-10 and Table 4-11 is shielded and
contains four cores. Typical capacitance for this type of cable is 130 pF/
m (i.e. from one core to all others and the shield connected together).
4.4.3 Motor winding voltage
The PWM output voltage can adversely affect the inter-turn insulation in
the motor. This is because of the high rate of change of voltage, in
conjunction with the impedance of the motor cable and the distributed
nature of the motor winding.
For normal operation with AC supplies up to 500 Vac and a standard
motor with a good quality insulation system, there is no need for any
special precautions. In case of doubt the motor supplier should be
consulted. Special precautions are recommended under the following
conditions, but only if the motor cable length exceeds 10 m:
• AC supply voltage exceeds 500 V
• DC supply voltage exceeds 670 V
• Operation of 400 V drive with continuous or very frequent sustained
braking
• Multiple motors connected to a single drive
For multiple motors, the precautions given in section 4.4.4 Multiple
motors on page 38 should be followed.
For the other cases listed, it is recommended that an inverter-rated
motor be used taking into account the voltage rating of the inverter. This
has a reinforced insulation system intended by the manufacturer for
repetitive fast-rising pulsed voltage operation.
Users of 575 V NEMA rated motors should note that the specification for
inverter-rated motors given in NEMA MG1 section 31 is sufficient for
motoring operation but not where the motor spends significant periods
braking. In that case an insulation peak voltage rating of 2.2 kV is
recommended.
Model
200 V Nominal AC supply voltage
Maximum permissible motor cable length for each of the following switching frequencies
0.667 kHz 1 kHz 2 kHz 3 kHz 4 kHz 6 kHz 8 kHz 12 kHz 16 kHz
01200017
50 m (164 ft)
37.5 m
(123 ft)
25 m
(82 ft)
18.75 m
(61 ft)
12.5 m
(41 ft)
9 m
(30 ft)
01200024
01200033
01200042
02200024
100 m (328 ft)
75 m
(246 ft)
50 m
(164 ft)
37.5 m
(123 ft)
25 m
(82 ft)
18 m
(59 ft)
02200033
02200042
02200056
02200075
03200100 100 m (328 ft)
75 m
(246 ft)
50 m
(164 ft)
37.5 m
(123 ft)
25 m
(82 ft)
18 m
(59 ft)
04200133
100 m (328 ft)
75 m
(246 ft)
50 m
(164 ft)
37.5 m
(123 ft)
25 m
(82 ft)
18 m
(59 ft)
04200176
Model
400 V Nominal AC supply voltage
Maximum permissible motor cable length for each of the following switching frequencies
0.667 kHz 1 kHz 2 kHz 3 kHz 4 kHz 6 kHz 8 kHz 12 kHz 16 kHz
02400013
100 m (328 ft)
75 m
(246 ft)
50 m
(164 ft)
37.5 m
(123 ft)
25 m
(82 ft)
18.25 m
(61 ft)
02400018
02400023
02400032
02400041
03400056
100 m (328 ft)
75 m
(246 ft)
50 m
(164 ft)
37.5 m
(123 ft)
25 m
(82 ft)
18.25 m
(61 ft)
03400073
03400094
04400135
100 m (328 ft)
75 m
(246 ft)
50 m
(164 ft)
37.5 m
(123 ft)
25 m
(82 ft)
18.25 m
(61 ft)
04400170
Normal capacitance
Shield or armour
separated from the cores
High capacitance
Shield or armour close
to the cores