Departure method; motor power, load type (starting torque) and speed control requirements The appropriate system is selected: DOL for small motors, star-delta or softstarter for fans/pumps, softstarter for high torque loads, and frequency inverter (VFD) if speed control is required.
Choice = power + starting torque + need for speed control.
Example calculation: 30 kW fan (low starting torque, no speed control) → star-delta or softstarter recommended.
Engine Starting Method Selection
See the appropriate starting method according to engine power and load type (DOL, star-delta, softstarter, VFD).
Notes: This recommendation is a general guideline; the final choice will be made considering grid constraints, start-up frequency, start-up time, and load moment of inertia. Star-delta configuration is only suitable for no-load/low-load start-ups.
How is it calculated?
- Enter the engine power (kW).
- Select the load type (fan/pump, conveyor, crusher).
- If speed control is required, check the box and press Suggest.
Frequently Asked Questions
When is the star-delta symbol used?
In medium-power engines that start at no-load or low load, it is not suitable for loads with high starting torque.
Softstarter or VFD?
If only a soft start is required, a soft starter is used; if speed/RPM control is also needed, a frequency inverter (VFD) is used.
Which method for a small engine?
If the network allows it, direct lane change (DOL) is the simplest and most adequate method.
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