SIEMENS
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Siemens D 83.1 · 2016
1
Introduction
General technical specifications
Converter operation – General information
■
Overview
(continued)
Typical voltage stress of motors for operation on the
SINAMICS G180 converter at 690 V
Motors of the 1PS or 1MD5 series with standard insulation are
designed for peak voltages up to 1500 V (IEC/TS 60034-25).
As an option, 1PS motors are also available with special
insulation for peak voltages of 2.25 kV. In this case, the
winding is suitable for peak voltages in accordance with
IEC/TS 60034-25 Curve B. Due to the space required by the
special winding insulation, this option can only be ordered for
frame size 160 and above. The possible power of the motor is
then 5 % lower than a motor with standard insulation. The limits
for peak voltage with regard to explosion protection, especially
for the terminal box, are applicable as specified in the
R20000 regulation.
Engineering information for converter operation
Admissible voltage stress
More stress is placed on the insulation of the motor winding with
converter operation than with line operation. The voltage stress
also depends on the type of converter used.
Voltage stress on a converter with pulse width modulation (PWM)
The PWM converter subjects the motor windings to wear and
tear mainly by quickly applying voltage pulses. Each switching
process of the converter releases a voltage wave onto the motor
supply cable that can result in excessive motor voltages due to
reflection (see diagram).
Typical progression of converter voltage
U
FC
and motor voltage
U
Motor
on the PWM converter (converter with and without output filter, length of
motor cable 100 m)
The maximum voltage is influenced by the rise time of the pulses
and by the length of cable used between motor and converter.
A d
v
/d
t
output filter at the converter can reduce the maximum
motor voltage to uncritical values. With the SINAMICS G180
converters, a high-quality d
v
/d
t
output filter is included as
standard. With converters without d
v
/d
t
output filters,
inadmissible voltage peaks can occur even with a relatively
short motor cable (approx. 10 m). With the d
v
/d
t
output filters
of the SINAMICS G180 converter, depending on the supply
voltage, cable lengths of 150 m (at 690 V) to 300 m (at 400 to
500 V) are possible. The admissible voltage stress for the motor
depends on the rise
t
r
of the converter output voltage. The
admissible voltage stress for our motors with standard insulation
(1.50 kV curve) is shown in the diagram below. Special insulation
is necessary for higher voltage stress (2.15 kV curve; on request,
additional charge).
Admissible voltage stress for motors with standard insulation
(
Û
LLmax
= Maximum value of phase-to-phase voltage)
The operation of the 1PS0/5 and 1MD5 motor series on Siemens
G180, G150, G130, G120 PM230, G120 PM240x, S150 and
S120 converters is possible in the standard version with a supply
voltage up to 500 V with a typical cable length up to 150 m.
Testing using the provisions set out in guideline R20000 is
necessary for other converter types or manufacturers.
Motor operation on converter with sine-wave filter
In special applications, e.g. with extremely long motor cables,
so-called sine-wave filters are used which result in a smoother
converter voltage than d
v
/d
t
filters. When a sine-wave filter is
used, it is important to note that a significant drop in motor
voltage of up to 15 % occurs. Under these operating conditions,
derating is necessary to prevent the motors from overheating.
For operation with sine-wave filters and the consequent
reduction of 10 to 15 % in motor voltage, the admissible power
ratings for converter operation must be similarly reduced by
10 to 15 %.
For the LOHER CHEMSTAR and LOHER VARIO series, it is
possible to dimension the motors for the reduced voltage at the
motor terminals that results from the converter, which can
prevent a reduction in power rating due to reduced voltage.
μs
V
400
800
1600
1200
2000
0
SINAMICS
G180 standard
filter
Typical
cable lengths up to
150 m
SINAMICS
G180 reinforced
filter
Typical
cable lengths
up to 300 m
Rise time
t
r
Characteristic A
from IEC/TS 60034-25
G_D083_EN_00045b
Peak voltage
U
0.0
0.4
0.8
1.2
1.6
2.0
2.4
2.8
3.0
Time
t
without filter
with filter
G_D083_EN_00046
U
Motor
U
FC
μs
2.15 kV
without filter for motors up to 690 V AC
without filter for motors up to 500 V AC
1.50 kV
kV
0.4
0.8
1.2
1.6
2.0
2.4
0.01
0.2
0.4
0.6
0.8
1.0
1.2
t
A
Û
LLmax
G_D083_EN_00047a
Time
t
t
A
U
Motor
0
10 %
90 %
100 %
© Siemens AG 2016