Description
Bosch Rexroth MHD093A-035-PG0-BA | AC Servo Motor
Product Introduction
The Bosch Rexroth Indramat MHD093A-035-PG0-BA is an MHD-series permanent-magnet synchronous servo motor intended for closed-loop machine-axis applications. Its 093 frame uses a 140/150 mm mounting flange and 130 mm centering diameter, while the integrated digital servo feedback system provides absolute position detection over more than 4,096 revolutions.
For retrofit and replacement work, the configuration details matter more than the MHD family name alone. This version provides 12.0 Nm continuous torque at standstill, natural-convection cooling, a plain shaft with shaft seal, and a side-B power connection. It is specifically configured without a holding brake, so the machine’s vertical-axis or gravity-loaded holding strategy must be checked before substitution.
MHD093A-035-PG0-BA
Key Technical Specifications
- Manufacturer: Bosch Rexroth Indramat
- Series: MHD Synchronous Motors
- Exact Model: MHD093A-035-PG0-BA
- Rexroth Order Number: R911291332
- Motor Technology: Permanent-magnet synchronous / brushless AC servo
- Motor Size: 093
- Motor Length: A
- Winding Code: 035
- Continuous Standstill Torque: 12.0 Nm
- Flange Size: 140/150 mm
- Centering Diameter: 130 mm
- Feedback: Digital servo feedback with integrated encoder
- Position Detection: Absolute, greater than 4,096 revolutions
- Measurement Method: Optical
- Shaft Design: Plain shaft
- Shaft Seal: Yes
- Holding Brake: None
- Cooling: Natural convection
- Protection Rating: IP65
- Insulation Class: F
- Operating Ambient Temperature: 0 to +40 °C
- Storage Temperature: -20 to +80 °C
- Maximum Installation Height: 1,000 m above sea level
- Power Connection: Output connector directed to side B
- Reported System Accuracy: ±0.5 angular minutes
The 12.0 Nm torque, 140/150 mm flange, 130 mm centering diameter, IP65 rating, Class F insulation, and environmental limits are consistently reported for this MHD093A configuration family.
Application Scenarios & Engineering Pain Points
1. CNC and Machine-Tool Axis Replacement
The MHD093A-035-PG0-BA can serve as a replacement motor where the existing machine uses a compatible Rexroth digital servo system.
Engineering issue: A physically similar MHD motor can still have a different winding, encoder configuration, shaft arrangement, or brake configuration. Match the complete ordering code rather than selecting by frame size alone.
2. Packaging and Indexing Equipment
The absolute multiturn feedback system is relevant to axes requiring position information across multiple motor revolutions. The published specification exceeds 4,096 revolutions of absolute position detection.
Pain point: Substituting a different feedback variant can prevent the drive from correctly identifying or commissioning the motor.
3. Material Handling and Transfer Axes
The 12.0 Nm continuous standstill torque provides a defined reference for low-speed holding and load calculations.
Pain point: This model has no holding brake. A gravity-loaded vertical axis should not rely on the motor alone to hold position after power removal.
4. Legacy Indramat Machine Retrofit
For machines using discontinued MHD motors, retaining the exact mechanical and feedback configuration can avoid unnecessary changes to mounting, coupling, cabling, and drive commissioning.
Pain point: Verify the existing motor’s complete nameplate before ordering. MHD093A-035 has multiple suffix configurations, including PG0, PG1, PG2, NG0, NG1, NP0, NP1, and PP variants.
QA & Live Testing SOP
1. Identity Verification
- Photograph and record the complete motor nameplate.
- Confirm MHD093A-035-PG0-BA.
- Cross-check order number R911291332.
- Confirm motor size 093 and winding code 035.
- Verify that the physical connector arrangement corresponds to the documented side-B configuration.
2. Mechanical Inspection
- Inspect the 140/150 mm flange and 130 mm centering pilot.
- Check the plain shaft for scoring, corrosion, bending, or coupling damage.
- Verify the shaft seal is intact.
- Rotate the shaft manually and check for abnormal bearing noise or roughness.
- Inspect connector threads, pins, seals, and housing damage.
3. Electrical and Feedback Testing
For a serviceable unit, use a compatible Rexroth drive/test system rather than applying uncontrolled external voltage directly to the motor.
Verify:
- Phase-to-phase winding resistance consistency.
- Insulation resistance using an appropriate motor test procedure.
- Feedback recognition by the compatible drive.
- Absolute multiturn position feedback.
- Encoder fault status.
- Controlled low-speed rotation.
- Direction of rotation.
- Current balance under controlled operation.
- Abnormal vibration or bearing noise.
4. Thermal and Functional Test
Run the motor under a controlled test load appropriate to the available Rexroth drive and motor data.
Record:
- Initial winding/motor temperature.
- No-load or controlled-load current.
- Feedback status.
- Rotation stability.
- Bearing noise.
- Temperature rise.
- Drive fault history.
5. Packaging
Use ESD-conscious handling for the feedback electronics and connector assemblies. Protect the shaft and centering surface from impact, cap exposed connectors, and use mechanical cushioning that prevents the motor from moving inside the shipping carton.
Field Engineer’s Pitfall Guide
❗ Do not confuse PG0 with PG1. The family contains multiple feedback and configuration variants. The complete suffix must match the machine’s original configuration.
❗ No holding brake is fitted. Do not substitute this motor into a vertical or gravity-loaded axis without verifying the machine’s external brake, counterbalance, or safety-holding arrangement.
❗ Winding code 035 matters. Do not select a replacement solely because it has the same frame. The drive’s motor parameters must correspond to the installed winding configuration.
❗ Plain shaft means no keyed-shaft assumption. Confirm the coupling or hub design before installation. The published configuration specifies a plain shaft with shaft seal.
❗ Do not infer electrical voltage/current from generic listings. Published third-party pages contain inconsistent generic electrical figures. Use the exact Rexroth motor documentation/nameplate and compatible drive data for commissioning rather than copying generic marketplace specifications.
Intent-Driven FAQ
Q: What is the exact part number for the Rexroth -035-PG0-BA?
A: The corresponding Rexroth order number is R911291332. The full motgnation is .
Q: What is the continuque of the ?
A: The published continuous torque at standstill is 12.0 Nm.
: Does the have a holding brake?
A: No. This exact configuration is documented without a holding brake.
Q: Whatr does the use?
A: It uses digital servo feedback with an integrated encoder and absolute position detection exceeding 4,096 revolutions.
Q: What shaft does this Rexroth servo motor have?
A: The exact configuration uses a plain shaft with shaft seal. Do not assume it has a keyway.
Q: What is the mounting flange size?
A: The published specification gives a 140/150 mm flange with a 130 mm centering diameter.
A: Natural convection is specified for this configuration. It does not require a separate forced-air or liquid-cooling circuit under the documented configuration.
Q: Is the suitable as a direct replacement for aMHD093A motor?
A: Not automatically. Verify the complete ordering code, winding, feedback system, shaft, brake status, connector orientation, mounting dimensions, and compatible drive parameters before approving a substitution.
