Motor Protection Function Of Soft Starter

- Oct 25, 2017-

function and characteristics of starter:

Limited by the level of science and technology at that time, the logic control loop consists of relays, starting mode for the traditional frequency-sensitive resistor step-down mode, the starting motor actuator is contactor. The control system wiring is complex, the fault point is many, to the motor protection function is not complete, the starting current is big, has the big impact to the factory electricity use, is unfavorable to the other equipment stable operation. The starter was used when the system was reformed at the beginning of 1997. Jump Starter The new control system solves many problems existing in the original control system, and is beneficial to the new computer monitoring system interface which is being comprehensively reformed, which lays a foundation for improving the overall automation level of the whole plant and realizing the reduction of people's efficiency.

Motor protection function

The motor protection function of starter is: Phase sequence protection, Jump Starter short phase protection, over-current protection, running over-current protection, running overload protection and motor long time can not complete the boot process protection. When the starter's protection function moves, Jump Starter the starter will produce the shutdown output and the reason is displayed directly on the Control Panel.

In the control panel of the starter, the motor current, alarm signal and parameter value can be displayed, the protection value of the motor is set in digital form, Jump Starter and the operation mode of the motor is operated.

The working principle of the starter is: After the starter receives the start command, it calculates the trigger output voltage signal of the controllable silicon to control the starting process of the motor. When the starting process of the motor is completed, the starter will control the AC contactor to absorb, shorten all SCR, Jump Starter so that the motor directly to the network operation to avoid unnecessary energy loss.

The starter adopts a three-phase parallel thyristor as a voltage regulator, which is connected between the power supply and the motor stator. This kind of circuit is such as three-phase full controlled bridge rectifier circuit. When starting the motor with starter, the output voltage of the thyristor increases gradually, Jump Starter and the motor accelerates gradually until the thyristor is fully guided, and the motor works in the mechanical characteristic of the rated voltage, which realizes smooth start, reduces the starting current and avoids starting the over-current tripping. When starting the starter motor, by gradually increasing the thyristor conduction angle, Jump Starter the starting current of the motor rises from zero to the set value. No impact on the motor, improve the reliability of power supply, smooth start, reduce the impact torque on the load machine, prolong the service life of the machine. First to see what the main features of the starter!

Performance characteristics of Starter

Soft starter adopts software control method to smooth the starting motor, and the control mode is soft (piece) control (electricity). The control results of the motor starting characteristics from "hard" smooth to "soft" smooth, it is called "soft start." Soft start is divided into two types: one is the use of variable frequency constant torque limiting start, the other is the use of thyristor voltage regulator start-up, also known as intelligent soft start.

1. Technical performance. The use of frequency conversion speed start, start-up with good static and dynamic performance, even at low speeds can also adjust the motor torque at will, can start the motor with constant torque, starting current can be limited to the rated current below. With intelligent soft start, Jump Starter the torque is reduced by two times of the voltage ratio at start-up, so the starting torque is very small. Starter has current feedback, can also be used constant current start, that is, in the start-up process to keep the starting current unchanged until the motor close to the synchronized speed. From the aspect of technical performance, Jump Starter the variable frequency speed regulation is applied to the load of the larger starting torque, generally is greater than the occasion, such as reciprocating air compressor, centrifugal separator, with load conveyor, crusher, spiral or such as rotary air compressor, centrifugal fan, centrifugal pump, no-load start-up of the conveyor and a variety of no-load start-up equipment.

2. Economic nature. It is twice or even three times times higher than the investment cost of intelligent soft start by using frequency converter to start speed. Jump Starter Combined with the above technical performance and economic, for the industrial and mining enterprises can actually promote the starting mode when the number of the latter.

Main characteristics of starter

1, in the structure of the use of motor starter as the control output of the implementation of components, control logic with PLC programmable controller, making the system structure simple and clear, using digital monitoring and digital settings, improve the reliability of the control system, but also easy to maintain. At the same time has the function of external control, according to the use of the connection, easy to control.

2, the motor starter to the motor to provide a smooth and gradual start-up process, reduce the starting current to the power grid or power generation equipment impact, the start current control in the safe range, improve the original control system due to the start of a large impact plant power supply and other equipment to affect the normal operation of the situation.

3, the start-up process using two-way SCR, Jump Starter after the START process, contactor short controlled silicon control mode, to avoid the use of contactor direct control motor to make contact easy to pull arc, adhesion, burnout and other failures of the occurrence of ENGINEERING China copyright, but also save energy.

4, soft start, soft stopping mode, reduce the vibration and noise of equipment, Jump Starter reduce mechanical stress, prolong the service life of power generation equipment and mechanical transmission system.

5, with Over-current, overload, power supply is not equal to a variety of protection functions, at the same time can detect the load involved (such as air compressor) system of a variety of adverse operating conditions, Jump Starter conducive to the safe operation of the protection equipment.

6. The display function on the control panel is easy to understand the operation of the equipment in the field.

7, the digital parameter setting and display function is intuitive, convenient, save time.

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