Siemens SIMODRIVE611D is a new generation of Digital AC servo drive controls the bus driver. It consists of two parts namely: power supply module + driver modules (power module). Power supply modules for NC and driving devices to provide control and power supply, bus voltage while monitoring power and module status. Drive module is comprised of two dual-axis module and single-axis module, dual-axis module driving two AC servo motors.

This module two electrolytic capacitors have burst, including a particularly serious, blasted the flower. Simultaneous measurement of two line fuses are not conducting.

The power module main circuit diagram, see figure below. DC bus Electrolytic Capacitor C1, C2, C3, C4 filter are sent after the modules IGBT1 and IGBT2 two inverters, two AC servo motor driven. See from the schematic diagram 4 filtering electrolytic capacitors work environments are the same, but why only CI, two C2 capacitors burst, but also very serious. C3, C4, two capacitors without loss. Carefully observe the circuit board found close to the Cl capacitor of a resistance Rl knee broken, according to the schematic diagram is not difficult to analyze, the culprit was that the resistance of the capacitor burst. C1, C2, C3, C4-4 22 formed in series with one capacitor filter circuits for two IGBT module input DC measurements. Capacitance parameters for 220 μg of F/385V, DC-bus voltage of about 530V. In order to ensure both series capacitor voltage is equal, in addition to the two capacitance specifications other than in strict accordance, but also separately in each capacitor shunt resistance equivalent resistance, to ensure even pressure. Circuit power, the capacitor can discharge through the resistor. According to the capacitor impedance Xc=1/2 pi-FC, in the DC circuit, frequency f is close to 0, and capacitive reactance of infinity. R1 after circuit breaker, DC bus voltage 530V R3 and R4 resistor directly into C1. Because of the pressure resistance of the resistance 82k ω, the concatenation of the resistance 164k ω. The resistance is too large, flowing current is very small. R3, R4-limiting effect, Cl breakdown process is a gradual process, and when C1 is the breakdown after a short circuit, DC bus voltage directly by Cl and C2, Due to large current and voltage, causing C2 an instant breakdown of the internal temperature rises sharply to explode, the breakdown at the same time two of the DC bus fuse is blown. So the result is the C1 top crack. C2 is cracked. After using capacitors, resistors, fuses of the same specification. After the measurement with multimeter short circuit, test OK on computer.