Why does the 3RW40 soft starter fail to start small-capacity motors and trigger an alarm?

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Question: Why does the 3RW40 soft starter fail to start small-capacity motors and trigger an alarm? Question: Why does the 3RW40 soft starter fail to start a small motor? Keywords: 3RW40, Small motor. Answer: When testing Siemens’ latest model of soft starter, the 3RW40, if the power of the motor connected to it is too low, or if there is no motor load at all, the soft starter will report an error and immediately terminate the starting process. This is a normal alarm signal; the customer need not worry. The 3RW40 series incorporates electronic overload protection internally; its principle involves using an internal current transformer to measure the current values of the three-phase load, and then providing protection based on the set current levels and tripping thresholds. It also incorporates a low current detection function; that is, when the load current falls below 20% of the soft starter’s rated current, the 3RW40 soft starter will issue an alarm and stop the starting process. Therefore, when performing debugging, the user must ensure that the capacity of the motor driven by the soft starter meets the minimum requirement of the soft starter’s rated capacity. At the same time, the overload protection setting on the soft starter panel should also be set according to the rated current indicated on the motor’s nameplate. A&