Why Is a Soft Starter Needed?
When an electric motor starts directly across the line (DOL starting), it typically draws a very high starting current—often 5 to 8 times its rated current. This sudden surge can cause several problems:
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Voltage drops in the power supply network
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Excessive mechanical stress on motor shafts, couplings, and driven equipment
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Increased wear and tear, leading to shorter equipment lifespan
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Higher risk of electrical and mechanical failures
A soft starter addresses these issues by limiting the starting current and torque, allowing the motor to ramp up smoothly to its rated speed.
Key Features of a Sosiat Soft Starter
Modern soft starters typically offer the following features:
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Soft start: Limits inrush current and starting torque
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Soft stop: Prevents water hammer in pumps and mechanical shock in driven loads
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Current and voltage control
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Motor protection functions such as:
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Overload protection
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Phase loss protection
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Phase imbalance protection
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Under-voltage and over-voltage protection
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Adjustable parameters for different load types