Configuring 6SE70 Drive Motor Parameter Identification

The engineer sees a terminal resistance or inductance value and needs to decide whether it represents one stator winding, the complete stator, or a rotor-stator combination. Start with the motor connection. A two-terminal measurement is an equivalent value seen through every conductive path between those terminals; it is not automatically a per-phase motor parameter.

Commissioning decision path

1. Identify the accessible leads. Record whether the motor exposes three connected line terminals or six separate winding ends. Do not move on until the actual star, delta, or disconnected-winding arrangement is known.
2. Isolate the motor. Disconnect the motor cable from the drive and other parallel circuits, prove the circuit de-energized, and measure at the motor terminals. A connected drive, cable, filter, contactor, or suppression component can change the reading.
3. Measure every comparable terminal pair. Record the meter resolution, lead resistance, and all three line-to-line results. Similar readings support a balanced winding set; one different result directs the investigation toward a winding, connection, or contact defect.
4. Interpret resistance from the connection. Apply the star or delta relationship only after confirming the links or internal connection.
5. Treat inductance as frequency-dependent. A terminal inductance reading is an equivalent input quantity under the instrument's test conditions, not a clean separation of stator and rotor leakage.
6. Use drive identification for the drive model. If the installed drive is a 6SE70, run the motor-parameter-identification portion of its commissioning program. Use manual measurements to validate wiring and plausibility, not to replace the identification routine.

Motor connection check

Before anything else, confirm how the windings are connected during the measurement. With only three accessible terminals, the ohmmeter sees multiple windings according to the internal or linked connection. With six isolated winding ends, each winding can be measured directly after removing the links.

For three equal winding resistances, let R_phase be one winding and R_LL be the measured line-to-line value:

Star: R_LL = 2 × R_phase, so R_phase = R_LL ÷ 2.

Delta: R_LL = R_phase || (2 × R_phase) = two-thirds of R_phase, so R_phase = 1.5 × R_LL.

These conversions require three balanced windings and negligible contact and lead resistance. If the readings differ materially, stop using the balanced formulas and test the individual windings and connections.

Resistance measurement checks

1. Compensate the test leads. Short the probes and record their resistance. Subtract that value if the meter does not provide lead compensation. Low-resistance windings can be comparable to the leads themselves.
2. Stabilize probe contact. Test on clean conductive surfaces with firm connections. A reading that changes with probe pressure indicates a contact problem rather than a stable winding value.
3. Compare like-for-like pairs. Take all readings with the motor at approximately the same temperature. Copper resistance changes with temperature, so temperature drift can imitate an imbalance.
4. Separate the cable when necessary. A measurement at the drive end includes motor-cable conductor resistance and every intervening connection. Repeat at the motor if the line-to-line values are high or unequal.
5. Check insulation separately. A normal terminal resistance does not prove that winding-to-frame or phase-to-phase insulation is healthy. Use the appropriate insulation test method with sensitive electronics disconnected.

A conventional ohmmeter primarily establishes DC continuity and equivalent resistance. It does not directly report the drive's complete stator-resistance model, which may account for the connection, cable, and identification conditions used during commissioning.

Inductance measurement mechanism

An inductance instrument applies an alternating test signal and calculates an equivalent inductance from the measured impedance and phase relationship. The displayed value depends on test frequency, signal amplitude, winding connection, magnetic state, rotor position, and the motor's construction.

The terminal result can include magnetizing behavior, leakage flux paths, winding resistance, and rotor coupling. Rotor currents and magnetic coupling change with excitation frequency and slip conditions. A stationary, low-level bench measurement therefore does not uniquely separate stator leakage inductance from rotor leakage inductance.

If leakage inductance must be established independently, use the motor test method and equivalent-circuit definitions specified by the applicable motor or drive documentation. Record the connection and instrument test conditions with the result.

Drive identification procedure

1. Confirm the drive identity. Verify that the installed unit is a 6SE70 before applying the product-specific commissioning path.
2. Confirm motor data and wiring. Enter the motor data requested by the commissioning program and verify that the physical star or delta connection matches the intended operating arrangement.
3. Remove conflicting conditions. Check for open contactors, unintended parallel loads, loose terminals, and external components that could prevent the drive from seeing the motor correctly.
4. Run motor parameter identification. Select the motor-parameter-identification portion of the commissioning program and follow its prompts. The drive performs the measurements needed for its control model.
5. Accept only a completed routine. Do not move on until the commissioning program reports successful completion. If it stops, use the displayed diagnostic and the drive documentation to identify the unmet prerequisite.

Do not substitute a line-to-line ohmmeter or inductance-meter value directly into an unidentified drive field. First determine whether that field expects a per-phase value, a line-equivalent value, or a parameter derived by the identification routine.

Result verification and recurring pitfalls

1. Compare resistance symmetry. Recheck all three terminal pairs using the same leads, contact method, and motor temperature.
2. Compare inductance under identical conditions. Keep the same connection, rotor state, test frequency, and instrument range for every phase comparison.
3. Review the connection conversion. A value converted with the star formula while the motor is wired in delta, or vice versa, is not usable.
4. Repeat identification after corrections. If wiring, motor data, terminal condition, or motor connection changes, rerun the 6SE70 motor parameter identification.
5. Perform the operational check. Run the commissioned system through its permitted operating range and watch the drive's current, speed response, and diagnostics. Investigate abnormal current imbalance, unstable control, or a new diagnostic before releasing the machine.

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