Siemens SINAMICS V20 (order codes 6SL3210…) is the volume-selling basic drive on packaging lines, pumps, fans, conveyors and mixers. Four frame sizes, FSA to FSD, cover 0.12–3 kW on single-phase 230 V and 0.37–15 kW on three-phase 400 V. Most of its fault codes clear with a parameter change, a re-terminated cable or a clean heatsink — not a new drive.
This guide covers the codes behind most V20 service calls — F1, F2, F3, F4, F5, F6, F11, F12, F20, F35, F41, F51–F52, F71–F85 and the A5xx warnings. Replacement units are listed in our SINAMICS V20 (6SL3210) and 6RA80/6RA70 spare drives range.
The BOP displays the number preceded by "F" and the fault icon stays lit until you acknowledge. The buffer keeps the last faults with time stamps, so capture it before you clear anything. Press OK to acknowledge, or pulse a digital input configured as fault acknowledge. The fault value r0949 separates hardware from software: 0 means the hardware reported the trip, 1 (sometimes 2) means the firmware detected it — on F1 and F2 that single digit is the difference between a board failure and a wiring fault.
Manifestations. Trips the instant the drive is enabled, sometimes before the shaft turns, and trips faster on each retry. A large frame may trip with an audible bang.
Root causes. Motor power P0307 not matching inverter power r0206; a short in the motor cable; an earth fault; incorrect stator resistance P0350; a mechanical jam; starting boost P1312 too high.
Repair steps. Disconnect the motor and try to reset. If F1 stays, the power stage is suspect. If it clears, megger the cable phase-to-phase and phase-to-earth, then turn the driven load by hand. Confirm P0304–P0311 against the nameplate — a motor swapped without re-commissioning is the most common cause. Lengthen P1120 and reduce P1312 until the trip stops.
Manifestations. Trips at the end of a deceleration ramp, or while a gravity load drives the motor faster than commanded.
Root causes. Supply voltage above the rating-plate limit; a deceleration ramp shorter than the load inertia needs; no braking resistor, or a failed one; Vdc controller disabled in P1240.
Repair steps. Check the supply against P0210, then lengthen ramp-down time P1121 until the trip stops — that alone resolves most F2 events, because a fast ramp on a high-inertia load pushes energy back into the DC link.
Manifestations. Trips shortly after a start command, or whenever a large load switches on elsewhere on the feeder; on 230 V units it is often the first thing seen after a brownout.
Root causes. A mains failure; an unbalanced or sagging supply; loose terminations that drop voltage under current; a blown input fuse on one phase.
Repair steps. Measure all three line phases at the drive terminals under load, not at rest, and re-torque the terminations. If the supply is sound, check the mechanics — a jammed machine that stalls the motor pulls the DC link down.
Manifestations. Runs 15–60 minutes and then trips, sooner on hot days or with the cabinet door closed. The heatsink is hot to the touch.
Root causes. Overload; inadequate ventilation; pulse frequency P1800 raised above default; ambient temperature too high; cooling fan not turning.
Repair steps. Power down, wait five minutes and confirm the DC link has discharged. Clean the heatsink fins with dry compressed air — dust and oil mist coat the metal and stop heat transfer. Confirm the fan turns whenever the drive runs.
Manifestations. F5 trips after a sustained overload; F6 trips when load is applied suddenly. Both point at duty cycle rather than wiring.
Root causes. Running beyond the load cycle with motor power P0307 above the inverter rating r0206; a ramp-up time so short that the drive draws current in a step.
Repair steps. Bring the load cycle within limits and check whether a larger frame size is needed. Lengthen P1120, and on F6 set P0290 = 0 or 2 so the drive trims output frequency instead of tripping. F5 will not clear until the inverter overload utilisation r0036 drops below the I²t warning level P0294, so a reset straight after the trip appears to do nothing.
Manifestations. Trips after minutes to tens of minutes under load, with the motor frame noticeably above normal.
Root causes. A real overload from binding, a worn bearing or a jammed conveyor; a cooling-type mismatch in P0335; rated current that no longer matches the nameplate; and on small motors below 15 Hz, a sensitivity of the I²t model rather than a real overheat.
Repair steps. Re-enter nameplate data P0304–P0311, confirm overload factor P0640 and cooling type P0335, and check alarm threshold P0604 against the insulation class. Then measure motor current and check the mechanics. Do not raise the threshold to silence the trip — that removes the protection that stops the motor burning.
F12 means the heatsink sensor circuit is broken — a failed sensor or an internal wiring break. It is not a cooling problem, and the power stack has to be opened, so treat it as a workshop repair. F20 is the more useful code: calculated DC ripple has exceeded a safe threshold, and the cause is almost always the loss of one mains input phase — a blown fuse, a tripped phase or a loose termination. Check the mains wiring and input fuses first.
F35 is not a root cause. The automatic restart facility used up the attempts allowed in P1211. Read the history beneath it: the code that started the cycle, usually F3 or F2, is what you have to fix.
F41 appears after motor data identification (P1900 = 2, closed with P3900). The fault value says which part failed: r0949 = 0 no load applied, so check the motor is connected; r0949 = 1 the current limit was reached; r0949 = 2 the identified stator resistance fell outside 0.1–100%. It almost always comes back to wrong nameplate data or wrong star/delta wiring.
F51 is an EEPROM failure, common after a long run of parameter changes. A power cycle clears it; if it returns, restore factory values for parameters you no longer need and cycle power again. F52 and F60 are software and ASIC timeouts where a power cycle is the only field action. F61–F64 concern cloning with an MMC/SD card — cloning failed, or the contents are invalid or incompatible. Remove the card and cycle power.
On a USS or MODBUS link (P0700 = 5, P1000 = 5, baud rate P2010, address P2011), F71 and F72 mean the setpoint was lost: check the master, the bus wiring, the termination and the address. F80 means the analog input signal has disappeared, and F85 is an external fault raised by a digital input. Host-side spares such as the S7-1500 CPU 1517-3 PN/DP (6ES7517-3UQ10-0AB0) are stocked for these rebuilds.
Alarms do not stop the drive. A501–A503 (current and voltage limits) and A504 (inverter overtemperature) tell you a limit is being ridden; A505 and A506 warn of I²t and IGBT junction-temperature rise; A507 repeats the F12 sensor problem in non-tripping form; A535 means the braking resistor is overloaded, normally from a deceleration ramp that is still too short.
Field-repairable: F1 where the megger points to cable or motor, F2 through F6, F11, F20, F35, F41 and F71/F72/F80/F85. Workshop or replacement: F12, F51 recurring after a parameter restore, and F52/F60 where the control electronics have failed. A V20 that will not reset with the motor disconnected is generally cheaper to replace than to repair. Our VFD and AC drive collection carries replacement units and spare modules.
Every 3 months: clean the heatsink fins and cabinet filters. Every 6 months: confirm the fan turns freely at full speed and record heatsink temperature under load. Every 12 months: torque the line and motor terminations, megger the motor and cable, and archive the parameter set and fault buffer before clearing it. Every 5 years, or at the first fan-bearing squeal: replace the cooling fan rather than waiting for F4. Most repeat F5 calls are a sizing problem, not a drive problem.
How do I reset a V20 fault? Press OK on the BOP, or pulse a digital input configured as fault acknowledge. Record the fault buffer first — a cleared buffer cannot be recovered.
F5 will not clear even after the fault has gone. Why? It latches until the inverter overload utilisation r0036 falls below the I²t warning level P0294. Leave the drive without load and it clears within a few minutes.
Are spare V20 units still available? Yes — SINAMICS V20 and 6RA80/6RA70 replacement drives are listed in our Siemens spare drives range, and because the parameter set can be cloned, a replacement is usually commissioned in minutes.
