Features and advantages of using electronic soft starters for a motor starting

What is a Soft Starter? 

A soft starter is a device that can be added to an electric motor for a different start method. The main reason behind using a soft starter is to reduce the strain on a motor when the power is turned on. A soft starter helps in the gradual starting of a motor by applying increasing voltages. So there is no sudden start or burst of power but a smooth acceleration. It prevents possible damage to a motor and subsequently the entire machine. A soft starter gives a steady and linear slope of power. There are different types of soft starters available which can let you adjust the starting voltage and amount of time to fully power up an electronic motor. 

Here are some of the features of an electronic soft starter: 

• Range setting adjustments of a working machine
• Variable characteristics of current, voltage and torque
• Bypasses power semiconductors after the motor starting to reduce loss
• Limited number of starts per hour depending on the starting conditions and specifications 
• Integrated into communication network 
• Integrated motor protection against overcurrent, undercurrent or failure 
• Designed to accelerate or decelerate electric motors 

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Why use a soft starter on a motor? 

Electric motors in commercial or industrial systems require a lot of electricity when they are accelerated. Using a soft starter reduces the torque and power load. It smoothens the operation process and avoids complications or sudden jolts in the machine. Here are some other advantages of using electronic soft starters: 

• A soft starter helps to limit the transient voltages and protects against sudden power surges when the machine is in operation or there is a power outage. 
• It helps in the smoother operation of the machine and reduces the risk of personal harm to the worker. 
• A soft starter is easy to operate and is suitable for most types of induction motors. You just have to get it hooked onto the device and it will work properly. 

• Using a soft starter can help to increase the life of the motor. A motor that otherwise runs on heavy currents is risked of damage and defects. 
• Soft starters also protect the motor from overheating as it limits the current supplied during the start. It is useful for applications that require the motor to start and stop multiple times. 
• Soft starters are energy efficient as they automatically reduce the load when the motor reaches full speed.
• Compared to other alternatives like a VFD, soft starters are much cheaper. 

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How does a soft start motor starter work? 

To understand the working principle of an electronic soft starter, we will need to know its components. A soft starter essentially has two major components: 

Power circuit: This consists of Triac, which is a series of back-to-back thyristors that regulate the voltage supplied to the motor. Through this circuit, the current is circulated to the motor. 

Control circuit: This circuit controls, monitors and protects the components of a power supply circuit. 

When a pulse is applied to a set of thyristors, it allows the flow of current to energize the motor. The angle of each pulse determines how much current can pass and for how long. Thyristors can control the variation of firing angles which generates a voltage at the output. This voltage is gradually increased until it reaches the nominal point required. The duration of the current flow can be controlled by the user by setting the parameters of a current flow. The current is slowly applied to the motor, which allows the soft starter to reduce torque and power load. The soft starter controls the amount of voltage running through the motor’s circuits and allows for a smooth progression of the current.