Zhejiang Shuyi Electric Co. Ltd

Soft starter is a kind of motor control equipment that integrates #softstart, soft stop and multi-function protection. Not only can the motor be started smoothly and without impact during the entire starting process, but also various parameters during the starting process can be adjusted according to the characteristics of the motor load, such as current limit value, starting time, etc. If the user wants to choose a #softstarter, it must be matched with a cabinet to form a #softstarter cabinet, in order to realize the value of the soft starter. So, when configuring the soft start cabinet, how to choose the online type and the bypass type? Before selecting the type, it is necessary to clarify the difference between online and bypass soft-start cabinets.

The entire startup process of the online #softstarter soft start, including the running process after the startup is completed, is all within the soft start. Without going through other external components, this leads to all the heat-generating parts, including the heat generated by up to 3.5-7 times the starting current at startup, and the heat generated during normal operation. This has certain requirements for the heat dissipation of the soft start, the heat dissipation of the entire cabinet, and the temperature of the power distribution room. If it is not maintained well, it will easily affect the life of the equipment. The advantage is that this starting method saves a contactor that switches to the power frequency when starting, and it takes a lot of space to place a high-current contactor in the power distribution cabinet and achieve good fan heat, and direct starting saves a lot of space. space, and even in some occasions, the incoming line contactor can be omitted in order to save space.

After the bypass #softstarter finishes starting (measured Ia, Ib, Ic<110%In), it will give a bypass switching signal to the bypass contactor KM3 by the R2A/R2C starting and switch to the power frequency. At this time, the internal circuit of the #softstarter will still provide various detection and protection functions, so the bypass contactor does not need to have a thermal relay to achieve overload, short circuit, phase loss, etc. protection. The soft starter with bypass will not have a large current of the main circuit through the inside after the start is completed (the current and voltage are read through the internal transformer). Therefore, only electronic components are self-heating, the heat dissipation pressure is reduced, and the lifespan is significantly increased. Therefore, if there is no special requirement for space, the connection method with bypass is basically adopted in various fields.

The difference between online soft start and bypass soft start:

1. Different structure and composition

The on-line soft-start cabinet takes the #softstarter as the main control element, and is equipped with switches, cabinets, etc. The bypass-type soft-start cabinet has more bypass contactors on the basis of the on-line soft-start cabinet, which is structurally the biggest difference.

2. The working principle is different

The thyristor plays a vital role in the online soft-start cabinet. The output voltage of the thyristor gradually increases, and the motor gradually accelerates until the thyristor is fully turned on. Avoid starting overcurrent tripping. When the motor reaches the rated number of revolutions, the starting process is over, and the thyristor continues to work to ensure the normal operation of the motor. The bypass soft-start cabinet replaces the thyristor that has completed the task with a bypass contactor after the motor reaches the rated number of revolutions to provide the rated voltage for the normal operation of the motor.

3. The service life is long and short

Since the thyristor of the online soft-start cabinet is always in working condition, under the premise of the same power and the same quality, the service life of the bypass soft-start cabinet is relatively longer.

4. Prices vary

The extra bypass contactor determines that the price of the bypass soft-start cabinet is higher than that of the online soft-start cabinet.


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#latestpowerstarter  #multifunctionalmotorsoftstarter  #softstarterby-passconnector

#functionsmartsoftstarter  #intelligentmotorsoftstarter

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