Siemens SIRIUS System Manual

3RW3 semiconductor motor control unit
SIRIUS System Manual
8-8
GWA 4NEB 430 0999-02b
Frequency converter
A frequency converter converts the AC voltage from the grid to direct volt-
age, which can then be converted to any voltage and frequency.
The illustration below shows how a frequency converter works:
Figure 8-3: Method of operation of a frequency converter
Disadvantages:
• Relatively complicated wiring needed in order to meet radio interference
suppression requirements; filters are often essential
• Line capacitances limit the lengths of motor feeder cables; it may be nec-
essary to use chokes, sinus filters, or even dV/dt filters.
• Expensive
• System startup is complex and time-consuming on account of the multi-
plicity of operating parameters
• It can be necessary to use shielded motor feeder cables
Advantages:
• Motor speed is variable; speed can be accurately pegged at constant lev-
els.
The U/f ratio remains virtually constant. It is therefore possible to achieve
high torques at relatively low currents.
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Siemens SIRIUS Specifications

General

Product brand name	Siemens
Series	SIRIUS
Coil Voltage	24V DC, 110V AC, 230V AC
Switching Capacity	Up to 10A
Mounting Type	DIN rail
Product designation	SIRIUS
Contact Material	Silver alloy
Contact Rating	Varies depending on the specific SIRIUS relay model (e.g., 6 A at 250 V AC, 10 A at 250 V AC)
Switching Voltage	Varies depending on the specific SIRIUS relay model (e.g., 250 V AC, 400 V AC)
Mechanical Life	Up to 10 million operations
Electrical Life	Up to 100, 000 operations
Operating Temperature	-25°C to +55°C
Protection Class	IP20
Size of relay base	Varies depending on the specific SIRIUS relay model