What is a soft start? Is it to change voltage or current or frequency?

The principle is different.

Soft starter is a new type of motor control device integrating soft start, soft stop, light load energy saving and a variety of protection functions, when starting the motor with a soft starter, the output voltage gradually increases, and the motor gradually accelerates until the motor works on the mechanical characteristics of the rated voltage.

Generally, step-down start means that the voltage change added to the stator winding of the motor during the start-up process is instantaneous and abrupt; Soft start, on the other hand, uses a voltage regulating device to automatically continuously and smoothly rise the starting voltage until the rated voltage is reached within the specified starting time.

The impact of the start-up mode on the power grid.

Comparing the various starting modes of asynchronous motors, when the motor is started at full voltage, the impact on the power grid is the largest, and the impact time is also the longest, while the impact of the usual step-down start on the power grid is relatively small, but because it involves a coil voltage switching process, there is an unfavorable link of secondary impact.

Soft start because a starting current that does not affect the power grid is set before starting, and the current is slowly increased to the set current, so there is no impulse current, the impact on the power grid is minimal, and the impact of the starting torque can be eliminated.

Summary. Kiss, here comes the answer! As follows: firstly, when the soft starter is set to start with a voltage ramp, the setting value of the initial starting voltage is the output voltage value when the soft start starts, which is generally 30% of the rated voltage.

Kiss, here comes the answer! As follows: First of all, when the soft start envy stove is set to start with a voltage ramp, the setting value of the initial starting voltage is changed to the output voltage value of the electric brother when the soft start starts, which is generally 30% of the rated voltage.

And then said. 1. Most soft starters can adjust the initial voltage, because the initial voltage determines the initial torque, the initial voltage is set according to the load torque, and the setting is too small, and it cannot be started or the starting time is too long; If the setting is too high, the start-up will cause mechanical shock, and the start-up current will be too large; For no-load start, the starting voltage can be set to 20%-40% of the rated voltage, and for medium load and heavy-load start, the starting voltage can be set to 40%-70% of the rated voltage. Shed Mega.

Final words 2. Start time and stop time to slow setting: the start time is set at about 10s, and the parking time is set within 20s. 3. Other parameter settings:

Some soft starters can be set to start the spike moment curve, and the voltage adjustment method is used to make the torque start and stop according to the set torque curve; Some soft starters have a setting of starting current limit, and the adjustment current is 10%-50% of the rated starting current; The soft starter has electronic overload protection and can be adjusted to a trip level of 10, 10A, 20 or 30 depending on the nature of the loadIn short, the commissioning is carried out according to the actual requirements of the load, and everything is fine after the installation of the rental mold, and it cannot be considered that the soft starter is limited to the function of limiting the starting current.

Kiss, follow the above method step by step, it's not a big problem.

Soft and hard starts operate differently when starting the motor, so the current required for starting is also different.

Hard start means that before the motor starts, the rated voltage and frequency are directly added to the motor, and the motor will instantly absorb a large amount of current for starting. Because the start-up of the motor will cause a sharp increase in current, which may cause a large impact on the power grid and distribution equipment, and will also increase the loss of the motor.

Soft start refers to the process of gradually accelerating the motor to the rated speed by controlling parameters such as voltage, frequency or time before the motor starts. During the soft start, the starting current of the motor will gradually increase, but the total current amplitude will not be as drastic as that of a hard start. Because the soft start can gradually accelerate the motor to the rated speed, this trillion positive can avoid the problem of the motor instantaneously absorbing a large amount of current to the power grid and power distribution equipment, and can also reduce the starting vibration and noise of the motor.

Therefore, there is a difference between the current size of the hard start and the soft start of the bright guess size. Under the same motor and load conditions, because the soft start can gradually accelerate the motor to the rated speed, the current required in the starting process will be generally smaller than the current of hard start, and at the same time, it can also reduce the starting noise and vibration of the motor, reduce equipment loss and failure rate.

After start-up, the operating current is the same.

In the general electronic circuit, a high-power negative temperature coefficient thermistor is used in series at the power input terminal to achieve soft start. There are also soft-start circuits composed of thyristors. It is necessary to choose according to the specific function of the circuit.

Summary. Pro, the equipment operating current is related to soft start. When the soft-start start-up is complete, the power supply is connected by the contact switch inside. At this time, the mechanical current is the normal motor current, and it has nothing to do with the internal components of the soft start.

Pro, the equipment runs without torrent and soft start. When the soft start is completed, the contact switch inside is connected to the electric source. At this time, the mechanical current is the normal motor current, and it has nothing to do with the internal components of the soft start.

Pro, the equipment operating current is related to soft start. When the soft-start start-up is complete, the power supply is connected by the contact switch inside. At this time, the mechanical current is the normal motor current, and it has nothing to do with the internal components of the soft start.

Generally, step-down start means that the voltage change added to the stator winding of the motor during the start-up process is instantaneous and abrupt; Soft start, on the other hand, uses a voltage regulating device to continuously and smoothly rise the starting voltage until the rated voltage is reached within a specified starting time. The impact of the starting mode on the power grid is compared with the various starting modes of the asynchronous motor, when the motor is started at full voltage, the impact on the power grid is the largest, and the impact time is also the longest, and the impact of the usual step-down start on the power grid is relatively small, but because it involves a coil voltage switching process, there is an unfavorable link of the secondary impact. Soft start because a starting current that does not affect the power grid is set before starting, and the current is slowly increased to the set current, so there is no impulse current, the impact on the power grid is minimal, and the impact of the starting torque can be eliminated.

If the motor is started directly, it will require 7 to 8 times the rated current.

The soft start plays the role of current limiting start, and the soft start of the external start is generally set to 3-4 times.

The soft start current is related to the load nature (constant torque, constant power, ventilator) and the starting mode (direct start, self-coupling step-down start, star delta, extended edge triangle, frequency sensitive resistance change, frequency conversion start).

In general, taking the Star-Delta starter 380 3 AC asynchronous motor as an example, it can be estimated like this:

110kw motor, rated working current of about 200A (can also be estimated by 2 times of power), when starting directly, the current is estimated by 6 times of rated current, about 1200A;

When the star-delta starts, the starting current is 1 3 when the direct start mode is 400A.

AC asynchronous motor, common 75kw, 90kw, 110kw, I have not seen the whole 100kw, the above takes 110kw as an example, and so on).