Allen-Bradley 1326AB-B720E-S2L Spare for 1326AB Automation

Allen-Bradley 1326AB-B720E-S2L Spare for 1326AB Automation

The Allen-Bradley 1326AB-B720E-S2L is a brushless AC servo motor from the 1326AB Series, engineered for high-dynamic motion control applications in industrial automation environments. As a maintenance-ready original spare, this unit is sourced, inspected, and tested to support rapid field replacement and minimize unplanned downtime in Kinetix and legacy Bulletin 1326 servo drive systems. Whether you are managing a planned shutdown, responding to an emergency motor failure, or building a strategic spare parts inventory for a multi-axis servo line, the 1326AB-B720E-S2L delivers the dimensional and electrical compatibility required for a direct drop-in replacement without system reconfiguration.

Maintenance engineers and procurement teams working with Allen-Bradley servo systems understand that motor failure in a production cell can cascade rapidly into broader line stoppages. The 1326AB-B720E-S2L is rated for continuous duty in demanding environments, including packaging machinery, material handling conveyors, CNC machining centers, and assembly automation. Its compatibility with Kinetix 6000, Kinetix 6200, and legacy 1394 GMC drive platforms makes it a versatile spare that covers multiple system generations within a single facility’s installed base.

Spare Maintenance Table

Maintenance Planning for Continuous Operation

When replacing the 1326AB-B720E-S2L in the field, a disciplined maintenance workflow extends well beyond the motor itself. Experienced maintenance engineers treat a servo motor replacement as an opportunity to audit the entire servo loop and associated control cabinet components. Begin by inspecting the 1326AB feedback cable assembly — encoder signal degradation is a leading cause of premature motor failure and nuisance faults, and a worn or damaged cable will compromise a new motor within weeks if left unaddressed.

Next, verify the condition of the Kinetix 6000 or 1394 servo drive module paired to this axis. Check DC bus voltage stability, regenerative braking resistor condition, and drive firmware revision compatibility with the 1326AB encoder protocol. If the drive has logged overcurrent or encoder loss faults prior to motor failure, the drive’s output stage IGBTs should be evaluated before re-energizing the replacement motor.

Power quality at the drive input is equally critical. Inspect the 1321 line reactor or EMC filter upstream of the servo drive for signs of overheating or insulation breakdown. A degraded line reactor can introduce voltage spikes that stress motor windings and shorten bearing life. Similarly, check the 1606 or 1794 power supply modules supplying 24 VDC logic power to the drive and I/O rack — unstable logic power is a common root cause of intermittent encoder communication faults that are misdiagnosed as motor failures.

For multi-axis systems, inspect the 1756-M02AE or 1756-M08SE servo motion module in the ControlLogix rack. Verify axis configuration parameters — motor catalog number, encoder resolution, and commutation offset — are correctly entered in Studio 5000 Logix Designer before commissioning the replacement motor. An incorrect motor catalog entry will result in improper current loop tuning and may damage the new motor during initial jogging.

Do not overlook the terminal block and wiring harness at the motor junction box. Inspect for fretting corrosion on power terminals, particularly in high-vibration environments. Replace any Phoenix Contact or Weidmüller terminal blocks showing signs of arc tracking or discoloration. For systems with safety circuits, verify that the MSR127 or GuardMaster safety relay controlling the servo enable circuit is functioning correctly and that the safe torque-off (STO) wiring to the drive is intact.

Finally, if the system includes a PanelView Plus HMI displaying axis status or fault codes, confirm that the HMI program reflects the correct axis tag mapping after the motor replacement. Mismatched axis tags can mask real faults and delay fault diagnosis during post-replacement commissioning.

Site Replacement Workflow

Step 1 — Isolation and Lockout/Tagout: De-energize the servo drive and confirm zero voltage on the DC bus using a calibrated meter. Apply LOTO per site procedures. Allow the drive capacitors to discharge fully (minimum 5 minutes after power removal).

Step 2 — Feedback Cable Disconnection: Disconnect the encoder feedback cable at the motor connector. Label the cable and inspect the connector pins for corrosion or bent contacts. Replace the cable if any damage is found — do not reuse a suspect cable with a new motor.

Step 3 — Power Cable Removal: Disconnect the motor power cable (U, V, W phases and PE ground). Inspect the cable insulation for heat damage or abrasion. Measure insulation resistance (IR) between each phase and ground — values below 1 MΩ indicate cable replacement is required.

Step 4 — Motor Removal and Inspection: Remove the motor from the machine coupling or gearbox. Inspect the shaft for fretting, corrosion, or mechanical damage. Check the mounting flange for flatness. Clean the mounting surface before installing the replacement unit.

Step 5 — Replacement Motor Installation: Mount the 1326AB-B720E-S2L replacement unit. Torque all mounting fasteners to specification. Reconnect power and feedback cables. Verify cable routing does not create strain on connectors.

Step 6 — Drive Configuration Verification: In Studio 5000, confirm the motor catalog number is set to 1326AB-B720E-S2L. Run the motor commutation test (if applicable to the drive type). Perform a controlled jog at low speed before returning the axis to automatic mode.

Step 7 — Functional Test and Handover: Run the axis through its full motion profile at reduced speed, then at full speed. Monitor drive current, velocity feedback, and position error. Document the replacement in the maintenance log and update the spare parts inventory.

Spare Parts Support FAQ

Q1: Is the 1326AB-B720E-S2L a direct replacement for other 1326AB frame B motors?
The 1326AB-B720E-S2L shares the same B-frame mounting dimensions as other 1326AB-B series motors, but torque rating, feedback type, and shaft configuration must be matched exactly to the original specification. Substituting a different torque rating (e.g., B440 or B1000) without updating the drive configuration will result in incorrect current loop tuning. Always verify the full part number before ordering.

Q2: What pre-shipment testing is performed on this spare?
Each 1326AB-B720E-S2L unit undergoes winding resistance measurement, insulation resistance testing (IR test at 500 VDC), encoder signal verification, and visual inspection of shaft, flange, and connectors before dispatch. A test report is available upon request. Units are shipped in anti-static, moisture-resistant packaging with foam protection to prevent transit damage.

Q3: How should this spare be stored in a maintenance inventory?
Store the 1326AB-B720E-S2L in a clean, dry environment at 10°C to 40°C with relative humidity below 85% (non-condensing). Keep the unit in its original packaging until installation. Rotate stock on a first-in, first-out basis. For long-term storage exceeding 12 months, inspect the shaft seal and bearing condition before installation and re-test insulation resistance.

Q4: What is covered under the 12-month warranty?
The 12-month warranty covers manufacturing defects, winding failures, encoder faults, and bearing failures under normal operating conditions. It does not cover damage resulting from incorrect installation, mismatched drive configuration, overvoltage events, or mechanical overload. Warranty claims are supported with a return merchandise authorization (RMA) process — contact [email protected] with the unit serial number and fault description to initiate a claim.

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