Output Current Ratings - Micromaster Integrated - Siemens COMBIMASTER Reference Manual

COMBIMASTER & MICROMASTER Integrated
REFERENCE MANUAL
8.6 Output Current Ratings
The MICROMASTER Integrated is designed to be fitted to a motor, and in most cases, to use
air from the motor fan for cooling of the inverter. For this reason it is not possible to specify
continuous current ratings which will be achieved under all circumstances. This section
provides information about the designed current ratings, and explains the factors which effect
the continuous ratings achievable when the inverter is installed on a motor.
Introduction
There are two factors in the design of an
inverter which define what current can be
delivered the motor :
The first factor is the selection of electronic
components. For example, the current rating of
the transistors in the output stage of the
inverter. This factor normally limits the peak
(short time) current that the inverter can
provide.
The second factor is the method of cooling of
the inverter. Whenever current flows through a
conductor, or an electronic component, heat is
generated. The cooling method chosen for the
inverter must be able to remove enough heat
so that when the inverter is run at its maximum
current rating continuously then
Voltage Class
Type
MI12
MI25
MI37
MI55
MI75
MI110
MI150 CS A Inverter
MI150 CS B Inverter
MI220
MI300
MI400
MI550
MI750
Siemens plc. 1999
© | G85139-H1731-U300-D2
- MICROMASTER Integrated
208 - 240V
P(kW) P(Hp) I (A)
0.12 0.16 0.8
0.25 0.33 1.7
0.37 0.50 2.3
0.55 0.75 3.0
0.75 1.00 3.9
none of the components in the inverter exceed
their rated operating temperatures.
With a standard inverter, the cooling method is
part of the design of the inverter, therefore it is
possible to specify the continuous current
ratings of the inverter when it is correctly
installed.
The cooling efficiency for MICROMASTER
Integrated is dependant upon the motor to
which it is fitted, and therefore the continuous
current rating must be determined by thermal
tests, when the inverter is fitted to the target
motor.
Designed Current Ratings.
The following table gives the designed current
ratings for the MICROMASTER Integrated. All
the inverters are capable of short-term
overload up to 150% of the values shown.
Power Ratings
380 - 500V
KVA P(kW) P(Hp)
0.32
0.67
0.91 0.37 0.50
1.2 0.55 0.75
1.5 0.75 1.00
1.10 1.50
1.50 2.00
1.50 2.00
2.20 3.00
3.00 4.00
4.00 5.30
5.50 7.30
7.50 10.0
I (A) KVA
1.1 0.76
1.4 0.97
1.9 1.3
2.7 1.9
3.75 2.6
4.0 2.8
5.9 4.0
7.7 5.2
10.2 7.0
13.2 9.0
17.0 12.0
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