Difference between Soft Starters and VFDs

1. Difference Between Soft Starters And VFDs Variable frequency drives and soft starters are widely utilized in industrial control and pump control. Both of them are semiconductor devices. VFD and soft starter panel although performing on similar principle are different from one another . 1. Why are VFDs and soft starters used for controlling/starting of motors? 2. Variable Frequency Drives. a. The principle of operation. b. Benefits of variable frequency drives. 3. Soft-starters a. The principle of operation. b. Benefits of sentimental starters. 4. Difference between Soft starters and Variable frequency Drives. 5. Selection – Where to use soft starters and where to use Variable Frequency Drive? 6. Summary Why are VFDs and soft starters used for controlling/starting of motors? When started by DOL, a motor would drain heavy inrush current. Frequent in rush current can decrease the lifetime of the motors. Also starting torque can't be controlled. so as to regulate the inrush currents VFDs and soft starters are used. VFDs and soft starter 1.Variable Frequency Drives VFDs control the motor by varying the frequency and voltage of the input supply. We all know that the speed of a motor is directly proportional to its supply voltage. during a VFD first, the input supply is converted into DC then it's again inverted back to AC of desired voltage. The speed of the motor is varied from zero to full speed by smoothly varying the availability frequency from 0Hz to rated motor frequency. VFDs offers smooth start, smooth stop and complete control over motor speed and torque.

2. Benefits of Variable Frequency Drives Power savings is that the principal advantage of any VFD. Complete control over motor speed are often achieved using VFDs. VFDs are often programmed to vary the speed of the motor it controls, supported factors like flow, pressure, etc. The third quadrant operation is feasible by employing a VFD. Dynamic torque control and excellent speed control. Best fitted to elevators, escalators, crushers, mixers, etc where speed must be maintained in spite of load variations. Advanced overload protection. 2. Soft starters Soft starters also are semiconductor devices wont to start or stop a motor. because the name indicates it offers a smooth start and smooth stop. Usually, soft starters are bypassed by a contactor- overload circuit because the motor gradually reaches its full-speed and gets back to action when the motor stops. Soft start and stop are achieved by temporarily lowering the motor terminal voltage. Principle of operation of sentimental starters A soft starter consists of three pairs of back to back connected semiconductor devices like thyristors for regulating the terminal voltage. These thyristors are switched alternatively to scale back the terminal voltage and inrush current. The terminal voltage of the motors are often controlled by varying the firing angles of the thyristors. Benefits of sentimental starters Effectively reduces inrush current during motor start. No harmonics are generated. Low cost compared to Variable Frequency Drives. Best fitted to conveyors, pumps and other belt-driven applications. Difference between Soft starters and Variable frequency Drives Soft starters:

3. In applications where speed control isn't essential. In low and medium torque applications. Reduce wear and tear during start and stop. In applications where initial cost is low. Variable Frequency Drives: VFDs are utilized in applications where complete control over speed is important . In high torque applications. Where the initial cost and size isn't a drag . Summary Variable frequency drives and soft starters are energy-efficient devices. Selection of 1 over the opposite depends on the appliance , control, cost and space factors. We Accu-panels are the premier organization engaged in manufacture and supply of incredible range of Variable Frequency Panels (VFD) and SOFT Starter Panels. These panels, also known as digital VFD drives play an important function in VFD squirrel cage induction and in motor control applications.