Configurable, communications-capable soft starter with
plug-in control signal terminals and interface for optional units:
- Operator control and programming unit
- Serial interface
- Fieldbus module
Application selector switch with user-programmable parameter sets for 10
standard applications
I2t controller
- Current limitation
- Overload protection
- Idle/undercurrent detection (e.g. belt breakage)
Kickstarting and heavy starting
Automatic control voltage detection
3 relays, e.g. fault signal, TOR (top of ramp)
Ten default parameter sets for typical applications can be simply called up with a selector switch.
Additional plant-specific settings can be defined with an optional keypad.
In three-phase regulator control mode, for example, three-phase
resistive and inductive loads – heaters, lighting systems, transformers – can be controlled with the DM4. Both open-loop and – with measured
value feedback – closed-loop control are possible.
Instead of the keypad, intelligent interfaces can also be used:
- Serial RS 232/RS 485 interface (configuration through PC software)
- Suconet K fieldbus module (interface on every Moeller PLC)
- PROFIBUS DP fieldbus module
The DM4 soft starters provide the most convenient method of implementing
soft starting. Because – in addition to phase failure and motor current monitoring – the motor winding temperature is signalled through the
built-in thermistor input, the soft starters eliminate the need for additional, external components, such as motor protective relays. DM4
conforms to the IEC/EN 60947-4-2 standard.
With the soft starter, reducing the voltage results in a reduction of
the high starting currents of the three-phase motor, although the torque is also reduced [Istartup ~ U] and [M ~ U2]. After starting, the motor
reaches its rated speed with all of the solutions described above. For starting motors at rated-load torque and/or for motor operation at a
motor speed that is independent of the supply frequency, a frequency inverter is required.
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