Siemens S120 frequency converter maintenance and configuration

The surface temperature of the braking resistor can exceed 80 ℃ and must be installed outside the cabinet or protected. The built-in normally closed temperature control switch should be connected in series to the emergency stop circuit or digital input of the control unit, set to OFF2 pulse blockade.

Activation of DC bus capacitor (Forming)

After long-term storage (over two years), the internal oxide film of the DC bus electrolytic capacitor in the SINAMICS S120 power module will degrade, and direct application of rated voltage may cause damage or even explosion of the capacitor. Therefore, devices stored for more than two years must undergo capacitor activation before being powered on for the first time.

Determine whether activation is needed: Check the serial number on the nameplate and confirm the production date based on the code (for example, "S" represents 2004 and "9" represents September in T-S920067000015). If it exceeds 2 years from the production date, it must be activated.

Activation circuit construction (taking 3-phase 400V module as an example):

Disconnect all loads and DRIVE CLiQ communication from the power module.

Prepare a three-phase switch, three 230V/100W incandescent bulbs (or three 1k Ω/100W resistors), and connecting wires.

Connect three light bulbs in series between the incoming terminals (L1, L2, L3) and the power supply (i.e. connect the light bulbs in series with the power module).

Turn on the power and observe the brightness of the light bulb. The light bulb should gradually dim from bright to dark, and eventually almost go out. If the light bulb remains bright, it indicates that there is a short circuit inside the module.

Keep the power on for about 1 hour (when using a resistor) or until the light bulb is completely turned off (when using a light bulb), allowing the capacitor to gradually form.

Remove the light bulb, connect it directly to the power source, and then turn it on for 30 minutes to complete the final activation.

Attention: The single-phase 220V module uses two light bulbs connected in series between L and N.

Selection of motor side output filter

When the length of the motor cable exceeds the allowable value (usually 50m for shielded cables) or the insulation level of the motor is low, an output filter must be selected.

Filter type, cable length (shielding), pulse frequency limitation

The motor reactor reduces the voltage rise rate (dv/dt) and limits the capacitive charging current to a maximum of 300m ≤ 4kHz

Dv/dt filter+voltage limiter limits dv/dt to<500V/µ s, voltage peak<1000V, maximum 300m ≤ 4kHz

Dv/dt filter compact+voltage limiter limits dv/dt<1600V/µ s, peak<1400V, maximum 100m ≤ 4kHz

The sine wave filter outputs an approximate sine wave, allowing the use of unshielded cables up to 300m or 450m (unshielded) fixed 4kHz

Important precautions:

When using a sine wave filter, the output current must be reduced by about 15%, and the filter configuration must be activated in the parameters (otherwise the control loop will be unstable).

It is strictly prohibited to operate dv/dt filters or sine wave filters without a motor connection, otherwise the filter capacitors may be damaged due to resonance overvoltage.

When the continuous operating frequency of dv/dt filter is below 10Hz, the thermal load will increase and the operating time needs to be limited (for example, every 5 minutes of low-frequency operation must be followed by 5 minutes of high-frequency operation).

Common fault codes and troubleshooting

The following table summarizes typical faults based on manuals and on-site experience:

Fault code (hexadecimal) Fault name Possible cause Solution

0x2200 Internal current power module hardware damage or motor short circuit check motor winding to ground insulation and phase to phase resistance. If normal, replace the power module.

0x2310 Short circuit to ground (U-phase) Motor or cable U-phase short circuit to ground measured with a megohmmeter. Check if the cable is damaged.

0x3210 Internal overvoltage DC bus voltage too high (regenerative energy feedback) prolongs deceleration time or adds braking resistor/braking module.

0x4210 High temperature (power unit) fan failure, ventilation obstruction, high ambient temperature. Check if the fan is rotating (refer to section 11.2.4 for replacing the fan), clean the heat sink, and reduce the ambient temperature.

0x6100 Internal software firmware error or parameter inconsistency. Download the firmware again, restore to factory settings, and debug again.

0x7520 Serial timeout (IBS) 160-IB1 module lost communication with the inverter (for InterBus option) Check the module plug and unplug again.

0x8100 Monitoring: Communication fault DRIVE CLiQ cable disconnected or poorly connected. Check the cable, unplug and lock it again.

0x8300 encoder fault encoder signal loss or power supply error check encoder cable shielding and wiring, use oscilloscope to measure A/B signal.

Read faults through STARTER: Connect the STARTER software, open "Diagnostics" ->"Fault memory" online, and you can see the current fault (r0949) and historical faults. The corresponding fault code can be queried in the List Manual.