PowerFlex 525 faults F005, F007, F013 — meaning, causes and what to check

Three faults, three different directions of cause

Following on from PowerFlex 525 fault F004, according to Rockwell's fault table (520-UM001O p. 161):

• F005 OverVoltage — the DC bus voltage has exceeded the maximum value.
• F007 Motor Overload — the drive's internal electronic overload protection has tripped.
• F013 Ground Fault — the drive has detected current flowing to ground at one or more of the U/V/W outputs.

All three are Type 1 faults: resettable, with auto restart possible through A541/A542 (520-UM001O p. 159); F013 alone is allowed only one auto restart attempt, regardless of A541 (p. 163).

Safety: the drive has no user-serviceable parts; do not disassemble the drive chassis (520-UM001O p. 159). Only qualified personnel should work on the power section, after isolating the supply and discharging the DC bus: wait three minutes and measure to confirm the bus is at 0 V; a blank display does not mean the capacitors have discharged (520-UM001O p. 13).

F005 — DC bus overvoltage

Trip levels (520-TD001I p. 10; 520-UM001O p. 169):

The input voltage tolerance is −15% / +10% (520-TD001I p. 10); on a 380…480 V drive the mains would have to rise to ~575 V AC to trip, so check the load side first, and the mains after that.

Rockwell gives two directions (520-UM001O p. 161): high mains voltage or transients, and motor regeneration during deceleration. Nuisance overvoltage trips usually come from fast deceleration, overhauling loads and eccentric loads (p. 13). Check high-inertia loads that stop quickly and downhill conveyors first.

Parameters:

• P042 [Decel Time 1]: deceleration time, default 10.00 s (520-UM001O p. 86). Rockwell recommends lengthening the decel time when F005 occurs (p. 161).
• A550 [Bus Reg Enable]: default Enabled (520-UM001O p. 135). The downside: the actual deceleration can be longer than the setting; if it extends beyond one minute, a Stall Fault is reported (p. 13). Rockwell notes (in the positioning application section) that with A550 disabled, the decel time must be set long enough to avoid F005 (p. 223).
• A437 [DB Resistor Sel] / A438 [DB Threshold]: when a braking resistor is used; with A437 > 0, A550 no longer has any effect (p. 119).

Braking resistor: every drive frame size has a built-in braking transistor (520-TD001I p. 3); Rockwell lists 5% duty cycle resistors for each size and gives guidance for selecting other types in PFLEX-AT001M pp. 11–22, 67–69 (520-TD001I p. 33). Setting A438 lower makes the brake act more often, so the resistor power rating must be checked; below 90% is usually not needed (520-UM001O p. 119). This is a design task, not a temporary fix in the field.

F007 — motor overload

F007 trips when the current exceeds P033 [Motor OL Current] according to class 10 protection (520-UM001O p. 84; 520-TD001I p. 10) — protection calculated for the motor, not an indication that the drive has failed.

Rockwell gives: a genuinely overloaded motor, or an unsuitable A530 [Boost Select] (520-UM001O p. 161). Also check:

• P033 set incorrectly. By default P033 equals the drive's rated current (p. 84). If a replacement drive or copied parameters leave P033 not matching the motor nameplate, the drive trips early or the protection is too loose.
• Long running at low speed. A493 [Motor OL Select] selects how the overload threshold is derated with frequency (No/Min/Max Derate) (p. 126) — with derating, the threshold at low frequency is lower.
• Mechanical binding or a gradually heavier load — bearings, gearbox, load increasing from batch to batch.

Two more points:

• d369 [Motor OL Level] displays the motor overload counter (p. 112) — monitor it while the machine runs.
• A494 [Motor OL Ret] defaults to Reset: the counter returns to 0 when power is reapplied (p. 126). Cutting the power to clear F007 and restarting straight away means the drive "forgets" that the motor has just been hot.

Distinguish this from F064 Drive Overload: the drive's own overload capability has been exceeded, Type 2 (520-UM001O p. 162).

F013 — ground fault on the output side

Rockwell's instruction is to check the motor and the external wiring to the drive outputs (520-UM001O p. 161); ground fault protection covers phase-to-ground on the output side (520-TD001I p. 10), so look first at the motor cable, the terminal box and the motor windings.

Rockwell requires a minimum insulation thickness of 15 mil (0.4 mm), no THHN-type wire in wet locations, and notes that cable should be selected for temperature, moisture and chemicals (520-UM001O pp. 33–34). In wash-down areas and humid processing areas, check the motor terminal box and the cable run through the wet area first.

F013 differs from the F038–F040 group (ground fault on an individual phase U/V/W) and F041–F043 (short circuit between two phases): these faults are Type 2, and Rockwell recommends replacing the drive if they cannot be cleared (520-UM001O pp. 161–162).

Read the fault data — before resetting

History of the last 10 faults (520-UM001O pp. 79, 144–145):

• b007…b009 [Fault 1…3 Code] and F604…F610 [Fault 4…10 Code]: fault codes in the order they occurred, b007 being the most recent; a repeated fault is recorded only once.
• F631 [Fault 1 Freq], F641 [Fault 1 Current]: output frequency and current at the time of the fault — compare the current with P033 when F007 occurs.
• F651 [Fault 1 BusVolts]: bus voltage at the time of the fault — the key data when F005 occurs.
• F611/F621 [Fault 1 Time-hr/min]: time in the drive's powered-up hours/minutes (d362/d363), to compare with the operating log.

If A541 is non-zero, the drive may have reset the fault itself many times (520-UM001O p. 160). Faults are cleared with Stop (when P045 [Stop Mode] allows it), by cycling power, or with A551 [Fault Clear] — selecting 2 "Clear Buffer" also erases the history (pp. 135, 160), so record it first.

When to suspect the drive itself

• F005, F007: the fault table does not point to replacing the drive (520-UM001O p. 161); deal with decel, load and parameters first.
• F038–F043 that cannot be cleared or F070 Power Unit: the fault table points to replacing the drive (520-UM001O pp. 161–162). For F013, the fault table only asks for the motor and output wiring to be checked; suspect the power section only when F013 keeps recurring after the cable and motor have been checked and passed. Separate cable–motor from drive only after isolating the supply and discharging the bus.

Example of drive maintenance under a yearly contract: URC Vietnam – yearly maintenance of 200+ drives and the control systems; see also breakdown support and maintenance.