Description
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Bosch Rexroth Indramat |
| Model / Type Code | MHD095C-058-NG1-RN |
| Order Number | R911295991 |
| Product Series | MHD Synchronous Motors |
| Product Type | Permanent-Magnet Synchronous Servo Motor |
| Motor Size | 095 |
| Motor Length | C |
| Winding Code | 058 |
| Continuous Standstill Torque | 23.0 Nm |
| Holding Brake Torque | 22.0 Nm |
| Nominal Speed | 4,000 rpm |
| Maximum Speed | 6,000 rpm |
| Theoretical Maximum Torque | 88.0 Nm |
| Peak Current | 117 A |
| Encoder | Digital Servo Feedback, HSF |
| Position Detection | Relative |
| Pole Pairs | 4 |
| Rotor Inertia | 0.00613 kg·m² |
| Cooling | Liquid-cooled configuration |
| Shaft | Plain shaft |
| Shaft Seal | Yes |
| Centering Diameter | 130 mm |
| Flange Size | 140 / 150 mm |
| Power Connection | Right-side power connector |
| Ambient Temperature | 0–40°C |
| Installation Height | Up to 1,000 m |
| Protection Rating | IP65 |
The product references agree on the principal identification: MHD095C-058-NG1-RN = R911295991, with 23.0 Nm continuous standstill torque, 22.0 Nm brake torque, HSF digital feedback, 130 mm centering diameter, and 140/150 mm flange dimensions.
One point deserves caution: available secondary listings disagree on the cooling description, with some presenting natural/surface cooling while another identifies the specific configuration as liquid-cooled. For procurement, the actual motor nameplate and Bosch Rexroth motor data sheet should control the cooling specification rather than a generic reseller database.
Application Scenarios & Pain Points
Servo motors usually fail at the worst possible time: during a production run, with the machine stopped and the original motor no longer readily available. The replacement has to fit mechanically and electrically, but the feedback and drive combination must also make sense.
- CNC machine tools: The MHD095C provides closed-loop servo motion for machine axes requiring controlled acceleration, speed, and position.
- Material handling: Its 23 Nm continuous standstill torque and 6,000 rpm maximum speed suit dynamic axis applications where both holding and rapid positioning matter.
- Packaging machinery: HSF feedback supports coordinated motion where position error quickly becomes visible in product registration.
- Automation and transfer systems: The MHD family is intended for rapid-response automation systems and is used with compatible digital drive controllers.
Field note: Before installing the replacement, inspect the shaft seal and connector area carefully. A motor can test electrically well while contamination around the connector or seal creates trouble after several production cycles.
MHD095C-058-NG1-RN
Related Products
- MHD095C-058-NG1-RN / R911295991 — Subject motor. The exact 095 frame, 058 winding, NG1 configuration, RN suffix, HSF feedback, and brake arrangement should be retained for a direct replacement.
- MHD115C-058-NG1-RA / R911295990 — Related MHD synchronous motor with a larger motor size. It may provide different torque characteristics but is not a drop-in replacement for the 095 frame.
- MHD095C-058-NG1-AN — Same general MHD095C/058 family designation but a different suffix configuration. Mechanical and feedback details must be checked before substitution.
- MHD095C-058-NG0-BN — Related MHD095C winding/frame configuration. The different option code means the complete electrical and mechanical configuration requires verification.
- MHD095B-058-NG1-RN — Similar 095-size MHD motor with a different motor-length designation. It should not be treated as identical to the “C” version.
- MHD112C-058-NP0-BN — Larger MHD motor configuration. Suitable for applications requiring different torque and mechanical dimensions, not a direct replacement.
- MHD071B-058-NP0-UN — Smaller MHD motor configuration. Useful where lower motor size and torque are acceptable, but it is not a substitute without mechanical and drive analysis.
- IndraDrive digital servo drives — Compatible drive selection must be based on the motor’s winding code, feedback type, current requirement, and complete type code. The motor itself does not contain the servo drive electronics.
- MHD131D-058-PG0-AN — Larger MHD-series motor with different frame and option coding; relevant as a family-level alternative rather than a direct replacement.
The Engineer’s Guide: Field Pitfalls to Avoid
WARNING 1 — Match the complete type code, not just “MHD095.”
MHD095 identifies the general motor size, but 058-NG1-RN carries important configuration information.
How to avoid it: Compare the complete motor code, order number R911295991, feedback type, brake, winding code, shaft arrangement, and connector configuration before approving the replacement.
WARNING 2 — Do not ignore the feedback encoder.
The -058-NG1-RN uses digital servo feedback (HSF) with relative position detection.
How to avoid it: Confirm that the installed Rexroth drive supports the exact feedback arrangement. A motor with a different encoder may fit the machine mechanically while failing during drive initialization.
WARNING 3 — Check brake torque and vertical-axis requirements.
This configuration has a 22.0 Nm holding brake.
How to avoid it: Verify the brake voltage, release behavior, brake torque, and machine safety requirements. For a vertical axis, never assume the motor brake is simply an operational substitute for a properly engineered load-holding system.
Frequently Asked Questions (FAQ)
What is Bosch Rexroth -058-NG1-RN?
It is a Bosch Rexroth Indramat MHD-series synchronous servo motor, identified by order number R911295991. The motor provides closed-loop rotary motion and uses HSF digital servo feedback.
The frame size is 095, with “058” identifying the winding configuration.
What is the continuous torque of -058-NG1-RN?
The documented continuous torque at standstill is 23.0 Nm. The integrated holding brake is rated at 22.0 Nm.
Do not confuse standstill continuous torque with available torque at every operating speed. Actual usable torque depends on drive configuration, speed, cooling, ambient conditions, and application duty cycle.
What encoder does this MHD motor use?
The motor uses digital servo feedback (HSF) with relative position detection.
This is a critical compatibility point. When replacing the motor, compare the feedback designation on the original motor with the proposed spare and verify drive recognition before commissioning.
What are the mounting dimensions?
The documented configuration uses a 130 mm centering diameter and 140/150 mm flange size. It has a plain shaft and shaft seal.
For a field replacement, also compare shaft length, shaft diameter, key arrangement where applicable, connector orientation, and mounting-hole dimensions. A nominally identical flange does not guarantee mechanical interchangeability.
Can I use another MHD095 motor as a replacement?
Not automatically. The MHD095 family includes different winding, feedback, shaft, brake, and option configurations.
Before substituting, compare:
- Complete type code
- Order number
- Winding code
- Feedback/encoder
- Holding brake
- Shaft configuration
- Cooling arrangement
- Motor constants
- Compatible drive firmware/configuration
This is especially important when performing an emergency legacy servo motor replacement.
What drive sh used?
The motor is intended to operate as part of a compatible Bosch Rexroth digital servo drive system. The exact drive must be selected from the motor data, including winding code, feedback, current requirements, and application speed/torque profile.
Do not select the drive solely from the motor’s nominal kW or frame size.
How shoefurb be tested?
For a production spare, I would request more than an insulation test:
- Verify .
- Record the motor nameplate and revision information.
- Check winding resistance and phase balance.
- Perform insulation testing within the manufacturer’s permitted procedure.
- Verify encoder feedback.
- Test brake engagement and release.
- Check shaft/bearing condition.
- Verify connector and cable interface.
- Run the motor under controlled load where practical.
- Document measured results and test date.
For an older servo motor, bearing noise, shaft play, encoder faults, and brake degradation are worth checking before the unit goes onto the critical-spares shelf.
