Most complete soft starter wiring diagram

- Sep 04, 2019-

The working principle of Soft starter

SoftStarter (SoftStarter) is a novel motor control device integrating soft starting, soft stopping, light load energy saving and multiple protection functions.The soft starter USES tri-phase parallel thyristor as voltage regulator, which is connected between the power supply and the stator of the motor.Such a circuit is a three - phase full - bridge rectifier circuit.When starting the motor with soft starter, the output voltage of thyristor gradually increases and the motor gradually accelerates until the thyristor is fully switched on. The motor works on the mechanical characteristic of rated voltage to achieve smooth start, reduce the starting current and avoid over-current tripping.

When the motor reaches the rated revolution, the starting process ends, and the soft starter automatically replaces the thyristor that has completed the task with bypass contactor to provide the rated voltage for the normal operation of the motor, so as to reduce the thermal loss of the thyristor, extend the service life of the soft starter, improve its working efficiency and avoid harmonic pollution of the power grid.The soft starter also provides soft stopping function. In contrast to the soft starting process, the voltage gradually decreases and the revolution gradually drops to zero to avoid the torque impact caused by free stopping.

Wiring diagram of five kinds of soft starter commonly used

A. CMC-L Series digital motor soft starter

Cmc-l series digital motor soft starter is a new type of motor starter and protection device which combines power electronics technology, microprocessor and automatic control.It can start/stop the motor smoothly without any step, avoid the mechanical and electrical shock caused by using the traditional starting way such as direct starting, star/triangle starting, autovoltage reducing starting, etc., and can effectively reduce the starting current and distribution capacity, and avoid the capacity increase investment.

  1. Basic wiring diagram

Soft starter terminals 1L1, 3L2, 5L3 are connected to three-phase power supply, 2T1, 4T2, 6T3 motor.When bypass contactor is used, bypass contactor can be controlled by built-in signal relay K2.

Cmc-l soft start wiring diagram

  2. Basic schematic diagram

CMC-L Soft start Schematic diagram


B. CMC-M Series digital motor soft starter

Cmc-m series digital intelligent motor soft starter is a new type of motor starter and protection device which combines power electronics technology, microprocessor and automatic control.It can start/stop the motor smoothly without any step, avoid the mechanical and electrical shock caused by using the traditional starting way such as direct starting, star/triangle starting, autovoltage reducing starting, etc., and can effectively reduce the starting current and distribution capacity, and avoid the capacity increase investment.

  1. Basic wiring diagram

Soft starter terminals 1L1, 3L2, 5L3 are connected to three-phase power supply, 2T1, 4T2, 6T3 motor.Soft starter can choose whether to detect phase sequence or not by setting parameters.When bypass contactor is used, bypass contactor can be controlled by built-in signal relay K2.

Cmc-M soft start wiring diagram

  2. Basic schematic diagram

CMC-M Soft start Schematic diagram


C. CMC-SX Series smart motor soft starter

Cmc-sx series intelligent motor soft starter is the only motor soft starter developed in China based on 32-bit ARM core microcontroller, which is a new intelligent asynchronous motor starter and protection device.It is a motor terminal control device integrating starting, display, protection and data collection.With fewer components, users can achieve more complex control functions.And Chinese and English interface display makes the operation easier.

  1. Basic wiring diagram

Soft starter terminals 1L1, 3L2 and 5L3 are connected to three-phase power supply, and soft starter terminals 2T1, 4T2 and 6T3 are connected to motor.Soft starter can choose whether to detect phase sequence or not by setting parameters.When bypass contactor is used, bypass contactor can be controlled by built-in signal relay K2.

CMC-SX soft start wiring diagram

  2. Basic schematic diagram

CMC-SX Soft start Schematic diagram

D. CT Series classification frequency conversion soft starter

CT series graded frequency conversion soft starter is a new type of starter with the international advanced level produced by power electronics technology, microprocessor technology and modern control theory technology.Through the control of thyristor, the starting characteristics of stepless frequency conversion, stepless voltage regulation, small starting current and large starting torque are achieved.Set start, display, protection, data collection in one.With fewer components, users can achieve more complex control functions.And Chinese and English interface display makes the operation easier.

  1. Basic wiring diagram

Soft starter terminals 1L1, 3L2, 5L3 connect to three-phase power supply, 2T1, 4T2, 6T3 connect to motor, B1, B2, B3 connect to bypass contactors.Soft starter can choose whether to detect phase sequence or not by setting parameters.When bypass contactor is used, bypass contactor can be controlled by built-in signal relay K2.

CT soft start wiring diagram


E. CMC-MX Series built-in bypass motor soft starter

Cmc-mx series built-in bypass motor soft starter is a new type of motor starter and protection device combining power electronics technology, microprocessor and automatic control.It can start/stop the motor smoothly without any step, avoid the mechanical and electrical shock caused by using the traditional starting way such as direct starting, star/triangle starting, autovoltage reducing starting, etc., and can effectively reduce the starting current and distribution capacity, and avoid the capacity increase investment.At the same time, cmc-mx soft starter has integrated current transformer and contactor inside, so users do not need external connection.

  1. Basic wiring diagram

Soft starter terminals 1L1, 3L2, 5L3 are connected to three-phase power supply, 2T1, 4T2, 6T3 motor.Without external bypass contactor, soft starter can choose whether to detect phase sequence by setting parameters.

CMC-MX soft start wiring diagram

  2. Triangular interior connection diagram

If the user USES triangle inner connection, the user must strictly follow the following picture to connect, otherwise it may cause motor or soft damage.The machine will judge the motor wiring before starting, and if the wiring is wrong, it will report the wrong wiring fault.

soft starter Triangular interior connection diagram