SIEMENS
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Siemens D 83.1 · 2016
1
Introduction
General technical specifications
Converter operation – General information
■
Overview
(continued)
Operating explosion-proof motors on a converter
For the safe operation of explosion-proof motors on a converter,
some basic rules must be observed. These rules are summa-
rized in the R20000 guideline. The current version of R20000 is
stamped on the rating plate.
The guideline must be complied with regardless of the type and
manufacturer of the converter.
If explosion-proof motors are to be operated at frequencies
above 60 Hz or 10 % above the cutoff frequency, it may be
necessary to perform a system test of the motor with the
converter.
The minimum requirement for the ordering options is described in
detail under "Power tables for converter operation.” The customer
is responsible for fulfillment of the regulations which may be
affected by the use of sine-wave filters, long cables, etc.
Operating dust explosion-proof motors
on a converter
Dust explosion-proof motors can be operated on a converter if
suitable monitoring equipment is used (e.g. PTC thermistor for
sole protection and certified evaluation units). The boundary
conditions described above also apply in this case and
compliance with the R20000 guideline, in particular, is essential.
For motors in the admissible type of protection for Zone 21, the
limits of the control range between 5 and 50 (60 Hz) also apply.
The maximum possible power in converter operation must not
exceed the power for line operation even in the case of higher
thermal utilization on the converter. In special cases, it may be
necessary to test the original system comprising the motor with
the converter, or a system comprising the same types.
If the motor is operated on SINAMICS G180 or on a different
SINAMICS converter with a suitable filter (e.g. d
v
/d
t
filter),
operation on line supplies from 500 V to 690 V is possible.
Operation on converters with vector control is admissible.
Compliance with the boundary conditions described in the
guideline No. 20000 must be ensured by the operating
company.
Siemens R20000 guideline for converter operation
of explosion-proof, low-voltage, three-phase motors
Converter operation of explosion-proof, low-voltage,
three-phase motors with type of protection
“Explosion-proof enclosure" and "Non-sparking"
for temperature classes T1 - T4
Explosion-proof three-phase motors may be operated on a
converter if the following conditions are satisfied:
1.
The output voltage of the converter shall be controlled such
that within the frequency range below the rated frequency of
the motor, an approximately linear relationship is maintained
between the voltage (fundamental component) and the
frequency (fundamental component), i.e. practically constant
machine flux in accordance with the rated data.
Operation above 1.1 times the rated frequency is only
admissible when the motor has an appropriate rating plate for
converter operation.
2.
I
continuous
is the value to which the current is restricted by
converter control in continuous duty.
The maximum value which can be set for
I
continuous
is the
continuously admissible rated motor current in accordance
with the rating plate on the motor or the value specified in the
documents that describe converter operation (R No.).
3.
I
temp
is the value to which the current is limited by converter
control in the case of temporary overloads of a maximum
duration of
t
temp
.
The maximum value which can be set for
I
temp
is 1.5 ×
I
continuous
.
4.
t
temp
is the amount of time for which the converter permits
I
continuous
to be exceeded.
t
temp
is to be set for a maximum of 60 seconds.
5.
The installed thermistors (e.g. PTC thermistors), which must
be suitable as sole protection, are to be connected to a
tripping device conforming to guideline 94/9/EC with a
prototype test certificate such as CK140: PTB 04 ATEX 3038
or CK144/145: PTB 02 ATEX 3059.
6.
Voltage peaks
(especially for pulse converters with long motor cable)
a)
The assessment of the terminal box in relation to
clearances and creep age distances allows for converter
operation with voltage peaks (
Û
LL
and
Û
LE
) of up to
Û
= 4600 V with explosion protection type Ex eb (formerly
Ex e) terminal boxes and up to Û = 3000 V for explosion
protection type Ex ec (formerly Ex nA) terminal boxes. This
is not permitted to be exceeded for reasons of explosion
protection.
b) To prevent partial discharges arising, with Ex ec
(formerly Ex nA) machines with standard insulation
the voltage at the motor terminals must also be limited in
relation to the rise time to values which fall below the
characteristic curve of the "withstand voltage curve"
diagram (see picture below). With Ex d motors, this is
recommended so as not to limit the service life.
Ruhstorf, 2016-04-01
Siemens Aktiengesellschaft
© Siemens AG 2016