Difference Between Soft Starter and Inverter – Reynolds

Soft starters and frequency converters are two completely different products. The inverter is used in the local area where speed regulation is required, and its output not only changes the voltage but also changes the frequency at the same time; A soft starter is actually a voltage regulator, which is used when starting a motor, and the output only changes the voltage and does not change the frequency. The inverter has all the functions of a soft starter, but it is much more expensive and has a much more complex structure than a soft starter.

Difference Between Soft Starter and Inverter – Reynolds

Difference Between Soft Starter and Inverter – Reynolds

Soft start

1. The thyristor communication voltage regulation circuit is a circuit that adjusts the conduction angle of the thyristor and cuts the waveform of sinusoidal communication electricity to obtain a uniform voltage with adjustable communication electricity;

2. This kind of communication voltage regulation circuit is applied to active heating temperature control circuit, stage dimming circuit and other load circuits that have nothing to do with the communication waveform but are only related to the uniform voltage;

3. However, some people and even so-called experts use this thyristor communication voltage regulating circuit for the start of asynchronous communication motors, and call it soft start;

4. Because the asynchronous communication motor works under the three-symmetrical sinusoidal communication waveform, it has a stable rotating magnetic field;

5. If the communication electricity that adjusts the conduction angle of the thyristor and cuts the waveform of the sinusoidal communication electricity is used for the asynchronous communication motor, a stable rotating magnetic field cannot occur;

6. The use of this communication waveform in the asynchronous motor completely destroys the starting performance of the asynchronous motor, the starting torque is low, the starting current is large, and there is no soft engine function that we fantasize about;

7. All soft-started motors are started when they are close to full voltage, which has a long starting time and a large starting current, which has a greater impact on the power grid;

8. The self-coupling step-down start, star-delta start-up, water resistance step-down start, etc., the step-down does not change the sine waveform, which are all good and effective starting equipment, which are better than soft starting;

Frequency converters

1. Regarding the inverter, it is a device that changes the frequency of three-phase sinusoidal communication;

2. Because it is an irreversible process to change the direct current into a sinusoidal communication waveform, it may be impossible to use the PWM widening carrier with a uniform voltage waveform of a sine wave to realize the frequency conversion intention of the sine waveform;

3. The uniform voltage waveform is the PWM widening carrier of the sine wave, which is realized by the switching action of the IGBT of the fully controlled equipment, and the practice of the output of the inverter is a periodic change rectangular wave with unequal width;

4. The asynchronous motor filters out the sinusoidal waveform from the PWM broadening carrier, and generates a stable rotating magnetic field required by the motor;

5. The synchronous speed of the asynchronous motor is changed by changing the frequency to realize the intention of frequency conversion speed regulation of the communication motor

The big differences are:

1. Soft engine is to try to cut and destroy the sine waveform, which is very simple, as simple as water flowing to a low place;

2. The inverter is trying to obtain a sine waveform with adjustable frequency, which is difficult! It's as hard as water to go high.

Difference Between Soft Starter and Inverter – Reynolds

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