SIKOSTARTTM 3RW34 - Siemens Industry, Inc.

TroubleshootingEnglishProblemResponse/Example1. Reversed Winding The motor runs but makes abnormal sounds and the running current is very high.2. Dead Ended Winding The soft starter trips out on a single phase fault. The line with the Dead End Winding will have nocurrent flow. The other two lines will have very large currents flowing.Note: Repeated attempts at starting with this connection can damage the soft starter.3. Dead Ended on All Windings The motor does not start. There is no current flow on any of the lines. The soft starter indicatorsLED 1 and LED 2 come on at the same time when a RUN command is given.4. Soft Starter to Fault Contactor LeadsSwapped5. Switch position SW1-3 does not matchactual circuit type.The motor runs but there is no current limiting during starting. The line and leg currents arebalanced. Due to the phase shift in the leg currents compared with the controller's internal timingfor starting control, there is no current limiting during starting.Incorrect firing pulses cause very high currents in the motor which can destroy the soft starter.L1L1L1L1L1L1L1L1T6T1T6T1T6T1T6T1L3L2L3T3T5T2T2T4L2L3L2L3T3T2T5T1T5 T2T4T4L2L3L2L3T4T3 T3 T5T2T6T5 T2T1T4L2L3L2L3T3T6T3T4T5T2T5T2T1T4L2Problem 1 Problem 2 Problem 3 Problem 4Table 16 : Inside Delta Wiring Problems10.4 Shorted SCR ChecksPerform one of the following checks to identify any shorted SRCs:These checks require no disassembly of the unit. Extensive SCR tests are detailed in later paragraphs.DANGERHazardous voltage. Will cause death or seriousinjury.Switch off the power before taking the measurements.High voltage is present on all soft starter componentsexcept heat sinks. All bus bars, terminals, snubberboards, and SCRs are energized at rated voltage.10.4.1 Resistance CheckUse an ohmmeter to check for shorted SCR(s) as follows.1. Disconnect and lock out all power to unit.2. Measure the resistance from the line to load terminals (L1 to T1, etc.), across each phase of the soft starter.3. Any reading of less than 3 kΩ indicates a shorted SCR that must be replaced. Note that the reading can be ashigh as 3 MΩ.32 3ZX1012-0RW34-1AN1