Reversing Siemens 1GG6 DC Motor Direction via SIMOREG Drive

Overview

The Siemens 1GG6 series is a long-running line of industrial DC shunt-wound motors typically deployed in machine tools, paper machines, wire-drawing lines, extruders, printing presses, hoists, and crane drives. The specific frame code 1GG6164-0JH40-6VV5-Z identifies a frame-size 160, four-pole DC motor with a separately excited shunt field. The trailing -Z suffix indicates a custom engineering package, and the -6VV5 order block specifies the option combination (terminal box position, encoder mounting, bearing insulation, and so on). Field and armature ratings must always be read from the motor's nameplate before any reconnection work.

When a 1GG6 motor is paired with a SIMOREG DC drive (6RA80 SIMOREG DC Master, 6RA70, or legacy 6RA24), reversing the shaft rotation direction is one of the most common commissioning tasks. Three valid methods exist:

1. Command-reference reversal — invert the polarity of the ±10 V speed setpoint or change the digital direction bit.
2. Digital-input reversal — assign a direction-select DI on the SIMOREG terminal block.
3. Electrical terminal reversal — physically swap the armature leads, the field leads, or the tachogenerator leads (one group only, not all three).

This article documents method 3, which is the correct technique when the drive parameters cannot be changed (locked password, OEM-commissioned drive, locked SIMOVIS or STARTER project, or a customer requirement for hard-wired reversal).

Motor Identification and Terminal Layout

Every 1GG6 motor exposes a standardized set of connection points in its main terminal box. The mapping used in this article follows the conventions in the Siemens catalog D 81.1 for the 1GG6 product family.

For a frame 160 1GG6 motor, the armature is typically rated 200–420 V DC and the shunt field at 180–310 V DC, with armature currents from 80 A to 360 A depending on the sub-designation. Confirm the exact voltage, current, RPM, and field amps from the nameplate before any work; the -0JH4 winding code corresponds to a specific voltage / speed rating that must be matched in the SIMOREG parameters.

SIMOREG Drive Configuration Context

The SIMOREG DC Master 6RA80 and the 6RA70 family accept a bi-polar ±10 V speed reference at terminals X174:5/X174:6. The drive generates the field current and controls armature voltage using a fully digital regulator. The default direction sense is set by parameter P080 / P082, but in many installed systems that parameter is locked or part of a frozen commissioning record. When parameter access is restricted, the wiring-change method is the only safe path.

The 6RA80 also provides built-in field-current reversal via parameter P082 if a parameter-only solution is preferred; this is the cleanest approach when the drive is still in the commissioning phase. Once the drive has been handed over to operations, a hardware reversal is often the only option.

Safety Prerequisites

Reversing a DC motor is straightforward but requires strict adherence to electrical safety procedure. The DC bus on a SIMOREG remains charged for several minutes after the AC feed is removed, and a separately excited motor can produce back-EMF on the armature terminals if the field is still energized or if residual magnetism remains.

1. Isolate the drive — open the upstream AC circuit breaker or contactor that feeds the SIMOREG.
2. Lock-out / tag-out (LOTO) — apply a personal padlock and tag to the disconnecting means per OSHA 29 CFR 1910.147 and EN ISO 14118.
3. Verify zero energy — measure the DC bus voltage at the SIMOREG with a category-III (or higher) multimeter. Bus voltage must be < 5 V DC before opening any motor terminal box.
4. Discharge confirmation — check the drive's status LEDs; the Ready LED must be OFF and the Fault LED OFF.
5. Identify conductors — label every wire at both the motor terminal box and the drive terminal strip with a unique ID before disconnecting. Use a continuity tester to confirm the mapping between motor terminals and drive terminals.
6. Document the change — record the new wiring in the motor's wiring diagram and in the SIMOREG commissioning sheet so the change is traceable during future maintenance.

Method A — Armature Reversal

Reversing the armature connections while leaving the field and tachogenerator unchanged reverses the motor's rotation direction without changing the drive's field polarity. This is the most common method for shunt-wound 1GG6 motors because the field current remains in the same direction, preserving the drive's field-weakening, field-economizing, and field-loss detection logic.

Procedure

1. Confirm the drive is isolated and locked out per the safety steps above.
2. Open the motor terminal box.
3. Locate the armature conductors on terminals 1C1 and 1D1. These are typically the largest-gauge wires in the box and connect to the brush holders.
4. Note the original wiring:
   • 1C1 → drive terminal 1C (armature positive, A+).
   • 1D1 → drive terminal 1D (armature negative, A−).
5. Disconnect both conductors and re-terminate:
   • Move the wire from 1C1 to 1D1 (it now goes to drive terminal 1D).
   • Move the wire from 1D1 to 1C1 (it now goes to drive terminal 1C).
6. Tighten terminal screws to the torque specified on the motor nameplate (typically 4–6 Nm for frame-size 160 terminals).
7. Do not change the field wires (3C, 3D) or the tacho wires (16, 17).

Result

By the Lorentz force law F = B × I × L, reversing the armature current while keeping the field flux B constant reverses the developed torque. The motor shaft rotates in the opposite direction without changing the field's excitation sense. The drive's field-current regulator (P082 on 6RA80) does not see a change, so no parameter adjustment is required for the field loop.

Method B — Field Reversal

Reversing the field connections while leaving the armature and tachogenerator unchanged also reverses rotation. This method is preferred when the armature wiring is difficult to access (for example, when multiple motors share a common armature bus in a sectional drive system) or when the field is fed from a separate field-supply module.

Procedure

1. Confirm the drive is isolated and locked out.
2. Open the motor terminal box.
3. Locate the field conductors on terminals 3C and 3D. These are smaller-gauge wires than the armature and are often run as a twisted pair.
4. Note the original wiring:
   • 3C → drive terminal 3C (field positive, F+).
   • 3D → drive terminal 3D (field negative, F−).
5. Disconnect and swap:
   • Move the wire from 3C to 3D.
   • Move the wire from 3D to 3C.
6. Do not change the armature wires (1C1, 1D1) or the tacho wires (16, 17).

Tachogenerator Polarity Reversal (Always Required)

Whenever either the armature or the field is reversed, the tachogenerator (or encoder) feedback signal must also be reversed. If it is not, the speed regulator sees negative feedback. The drive interprets the regulator error as "actual speed is below setpoint" and ramps the armature voltage toward maximum. The result is a runaway condition that ends in an F60005 overspeed trip.

DC Tachogenerator Procedure

1. Locate the tacho conductors at the drive terminal strip. On a 6RA70 the tach lands on XT:103 (signal+) and XT:104 (signal−). On a 6RA80 the equivalent is on the analog tach interface (X173).
2. Swap the conductors:
   • Move the wire from motor terminal 16 to drive XT:104.
   • Move the wire from motor terminal 17 to drive XT:103.
3. Confirm polarity with a voltmeter: with the motor rotated in the desired forward direction (by hand or a low setpoint), the voltage at XT:103 must be positive with respect to XT:104.

Incremental Encoder Procedure (Alternative)

If the motor is equipped with an incremental encoder (typical 1GG6 option code includes a Hübner or Leine & Linde encoder), swap the A and A\ phases on the encoder interface card rather than swapping an analog tacho:

• 6RA80 encoder card: swap terminals X172:6 and X172:7 (track A and track A\) on the Sensor Module.
• 6RA70 encoder card: swap terminals X172:7 and X172:8 on the encoder interface.

If the drive continues to indicate negative speed after the swap, instead invert the encoder count direction in parameter P741 (6RA70) or P043.002 (6RA80).

What NOT to Do

The most common wiring error is to swap both the armature and the field at the same time. Doing so brings the rotation back to the original direction, doubles the wiring-error risk, and may also confuse the drive's field-loss detection (P390 on 6RA70, F60004 on 6RA80) if the field leads are not landed in the correct order.

The second most common error is to swap the armature and tacho but leave the field alone, then later swap the field as well. Once the tacho is re-swapped again the rotation will revert. Always plan the change so that exactly one of {armature, field} is reversed, and the tacho is reversed exactly once.

A third, less obvious error is to swap the field wires at the motor but not at the drive, leaving the drive's F+ / F− output in the same sense. This is a wiring-only change in the motor box and is acceptable, but it must be documented because the field current now flows in the opposite direction inside the motor relative to the drive's labeling.

Verification Procedure

After the reversal and re-termination, perform the following checks before powering the drive.

1. Visual inspection — confirm all terminal screws are tight and no stray wire strands are present at any of the modified terminals.
2. Insulation resistance test (megger) — apply 500 V DC between each conductor and ground. A healthy 1GG6 motor shows > 100 MΩ. The minimum acceptable value is 1 MΩ per kV of rated voltage plus 1 MΩ, per IEEE 43.
3. Continuity check — verify the conductor mapping matches the motor's wiring diagram. With the drive still de-energized, ring out each pair (1C1↔drive 1C, 1D1↔drive 1D, 3C↔drive 3C, 3D↔drive 3D, 16↔XT:103, 17↔XT:104) and confirm continuity with no cross-connections to ground.
4. Power-on sequence:
   • Close the upstream breaker.
   • Wait for the SIMOREG to complete its self-test (typically 5–10 seconds on 6RA70, 8–15 seconds on 6RA80).
   • The drive should display Ready (o0.0 on 6RA70, r0000 = 0100 on 6RA80) with no active fault.
5. No-load test — issue a small speed setpoint (5–10% of rated speed) and observe the rotation direction with a tachometer or strobe. Confirm the direction matches the new requirement.
6. Load test — apply a small mechanical load and verify that the drive holds the setpoint without oscillation. If the speed oscillates or the drive faults on overspeed, the tacho leads are still in the wrong polarity.
7. Brake check — if the motor is equipped with a holding brake, verify that the brake releases and engages correctly in the new direction. Pay particular attention to brake torque direction; some 1GG6 options use a spring-set / electrically-released brake whose torque is independent of rotation, while others use a direction-sensitive servo brake.

Fault Diagnosis Matrix

Commissioning Notes for Specific SIMOREG Models

6RA24 (legacy)

The 6RA24 uses field terminals labeled F+ and F− on the field-supply module (typically a separate chassis in the cabinet). The wiring procedure is identical to the 6RA70, but confirm that the field-economizing threshold (parameter P106) and the field-current rating (parameter P101) match the motor's nameplate. The 6RA24's analog tacho input is on terminals 65/66 of the basic unit; on the motor side these map to tacho leads 16/17.

6RA70

Use DriveMonitor (SIMOVIS) or the STARTER commissioning tool to verify the following parameters against the 1GG6 nameplate before the first run:

• P100 — armature rated current (A)
• P101 — armature rated voltage (V)
• P102 — field rated current (A)
• P103 — speed at rated armature voltage (RPM)
• P104 — field weakening threshold (RPM)

The default P080 setting assumes positive setpoint = positive rotation. If you have physically reversed the motor by swapping the armature, leave P080 at 0 and treat the new wiring as the new baseline. If you physically reversed the field, set P080 to 1 to keep the analog reference convention consistent (positive setpoint = positive rotation as defined by the new field polarity).

6RA80 (SIMOREG DC Master)

The 6RA80 is configured from the AOP30 operator panel, the STARTER tool, or TIA Portal. Verify the following before the first run:

• P50051 — motor armature rated current (A)
• P50052 — motor field rated current (A)
• P50053 — motor speed at rated armature voltage (RPM)
• P50076 — tacho type (DC analog / incremental encoder / resolver)

The 6RA80 has built-in field-reversal logic in parameter P082. If a parameter-only solution is acceptable, set P082.001 = 1 and the drive handles the field-current reversal automatically, eliminating the need to swap the field wires physically. This approach also keeps the tacho polarity correct without any change, because the drive's internal current regulator inverts the field reference symmetrically.

1GG6 Order Code Interpretation

The full order code 1GG6164-0JH40-6VV5-Z decodes as follows:

For the exact rating table, refer to the Siemens 1GG6 catalog (D 81.1) and the motor's nameplate. Always confirm voltage, current, RPM, and field amps from the nameplate before performing any wiring work.

Field-Commissioning Checklist

1. Verify the drive is locked out and the DC bus is discharged (< 5 V DC measured at the SIMOREG).
2. Confirm the wiring diagram and mark the change on the as-built drawing.
3. Perform the armature or field swap (one only).
4. Reverse the tachogenerator or encoder feedback leads.
5. Megger the armature, field, and tacho windings to ground (> 100 MΩ).
6. Torque all motor terminal screws to the nameplate value.
7. Power up the SIMOREG and verify the Ready status with no active faults.
8. Run at 5–10% speed, no load; confirm the direction with a handheld tachometer.
9. Run at full speed, no load; confirm the drive holds setpoint without oscillation.
10. Run under load; confirm stable speed regulation and no F60004 / F60005 / F60031 faults.
11. Update the wiring diagram, the SIMOREG commissioning sheet, and the motor's nameplate sticker (if a direction arrow is fitted).
12. Brief the operations team on the new rotation convention and the modified terminal labeling.

FAQ