Shanxi soft starter manufacturers point out that there are three common types of main wiring used in Shanxi motor soft starter, and their characteristics are as follows:
1. Built-in bypass main wiring
Its main wiring is almost the same as that of the on-line type, and its advantage is that it is unnecessary to install a fast fuse because of the short-term operation of the thyristor. The overload protection of the motor is realized by the controller with soft starter, which not only surpasses the electronic thermal relay in function and performance, but also will not misoperate due to the harmonic current of the main circuit and external interference.
2. Online main wiring
All soft starter controllers have motor overload protection. When the soft starter is running online, the controller of the soft starter can overload the motor, and no thermal overload relay is required. Because the harmonic current after SCR is very large, electronic thermal overload relay cannot be installed, otherwise the misoperation of thermal relay will make the system unable to work normally. Because SCR is expensive and difficult to replace, in order to protect SCR, fast fuse should be used to prevent short circuit at the lower mouth of soft starter from burning SCR.
3. Bypass type main wiring
The soft starter can’t run without bypass contactor, so it is available in both main wiring schemes. The function of the contactor at the upper mouth of the soft starter is the same as that in the online operation mode, and it will not be repeated here. Emphasis is placed on the thermal relay. It is better to install it at the lower port of the bypass contactor without starting current, especially for the electronic thermal relay, because the current harmonic after passing through the soft starter can interfere with the misoperation of the electronic thermal relay and stop the motor. In addition, there is no need to install a quick fuse for the short-term operation of the thyristor, so there is no quick fuse in the main connection scheme.
If you need to know more about Shanxi motor soft starter, you can contact our Shanxi soft starter manufacturer.