Rexroth MHD115C-058-PG1-BA | Absolute Encoder Motor

Description

Rexroth MHD115C-058-PG1-BA | Absolute Encoder Motor

 

Product Introduction

The Bosch Rexroth Indramat MHD115C-058-PG1-BA is a large-frame MHD permanent-magnet synchronous servo motor designed for closed-loop industrial motion systems. The exact configuration uses motor size 115, length C, winding code 058, a 192 mm mounting flange, and a 180 mm centering diameter. Its PG1 feedback configuration provides digital servo feedback with integrated absolute position detection over more than 4,096 revolutions.

This configuration is distinguished by its integrated 70 Nm holding brake and 70 Nm continuous standstill torque. The motor uses a plain 38 mm shaft with an 80 mm shaft extension, shaft seal, side-B power connection, and IP65 protection. Published documentation identifies natural convection and surface cooling for this configuration; the exact machine installation should determine which permitted cooling arrangement is being used.

Key Technical Specifications

• Manufacturer: Bosch Rexroth Indramat
• Series: MHD Synchronous Motors
• Exact Model: MHD115C-058-PG1-BA
• Rexroth Order Number: R911290479
• Motor Technology: Permanent-magnet synchronous servo motor
• Motor Size: 115
• Motor Length: C
• Winding Code: 058
• Continuous Torque at Standstill: 70.0 Nm
• Holding Brake: Integrated
• Holding Brake Torque: 70.0 Nm
• Brake Voltage: 24 VDC
• Brake Current: 1.29 A
• Brake Connection Time: 53 ms
• Brake Disconnection Time: 97 ms
• Feedback: Digital servo feedback with integrated encoder
• Position Detection: Absolute, greater than 4,096 revolutions
• Measurement Method: Optical
• Flange Size: 192 mm
• Centering Diameter: 180 mm
• Shaft Design: Plain shaft
• Shaft Diameter: 38 mm
• Shaft Extension: 80 mm
• Shaft Seal: Yes
• Cooling: Natural convection and surface cooling
• Protection Rating: IP65
• Insulation Class: F
• Power Connection: Output connector, directed toward side B
• System Accuracy: ±0.5 angular minutes
• Operating Ambient Temperature: 0 to +40 °C
• Storage Temperature: -20 to +80 °C
• Maximum Installation Height: 1,000 m above sea level
• Motor Weight: Approximately 55 kg
• Additional Brake Weight: Approximately 3.8 kg

The exact configuration sources agree on the 70 Nm brake, 70 Nm standstill torque, 180 mm centering diameter, 192 mm flange, 38 mm shaft, 80 mm shaft extension, IP65 rating, and PG1 absolute feedback.

 

Application Scenarios & Pain Points

1. Large CNC and Machine-Tool Axes

The MHD115C-058-PG1-BA is suited to high-torque closed-loop machine axes where the controller and drive system are already based on compatible Rexroth architecture.

Engineering pain point: A replacement motor must match the original winding and feedback configuration. Substituting another MHD115C motor based only on the 115 frame can create drive-commissioning or feedback-compatibility problems.

2. Vertical or Gravity-Loaded Servo Axes

The integrated 70 Nm holding brake is particularly relevant where the machine requires mechanical holding when the servo system is disabled.

Engineering pain point: Brake torque must not be treated as available dynamic motor torque. The machine’s vertical-load calculation, brake stopping requirements, and safety circuit must be evaluated separately.

3. Heavy Material-Handling and Transfer Equipment

The 70 Nm continuous standstill torque provides a substantial stationary torque reference for axis sizing and load calculations.

Engineering pain point: The 55 kg motor mass alone can affect machine-frame loading, mounting hardware, shipping, and field replacement procedures. The brake adds approximately 3.8 kg according to the published configuration data.

4. Legacy Indramat Machine Retrofit

The MHD115C-058-PG1-BA can be relevant to legacy machine restoration where preserving the original mounting, feedback, brake, and connector arrangement is preferable to redesigning the axis.

Procurement pain point: The exact order code R911290479 must be matched. The family includes numerous 024, 035, and 058 winding/feedback combinations, so a generic “” search is insufficient.

5. Printing and High-Precision Automation

The MHD series is used in closed-loop motion applications including machine tools and printing equipment. The PG1 configuration provides absolute multiturn feedback exceeding 4,096 revolutions.

Engineering pain point: Absolute feedback does not eliminate the need to verify the connected Rexroth drive’s supported motor data and commissioning parameters.

 

QA & Live Testing SOP

1. Identity and Configuration Verification

Before electrical testing:

• Photograph the complete motor nameplate.
• Confirm MHD115C-058-PG1-BA.
• Confirm order number R911290479.
• Verify motor size 115.
• Verify length C.
• Verify winding code 058.
• Confirm PG1 feedback configuration.
• Confirm the physical brake is installed.
• Record any nameplate revision or serial information.

2. Mechanical Inspection

Inspect:

• 192 mm mounting flange.
• 180 mm centering pilot.
• 38 mm plain shaft.
• 80 mm shaft extension.
• Shaft seal.
• Bearing condition.
• Motor housing.
• Power connector.
• Feedback connector.
• Brake assembly.

Manually rotate the shaft and check for abnormal bearing noise, binding, roughness, or mechanical interference.

3. Brake Verification

Because the BA configuration includes an integrated brake:

• Verify brake wiring and connector condition.
• Check brake coil resistance against the applicable Rexroth service specification.
• Apply controlled 24 VDC only with an appropriate test setup.
• Verify mechanical release.
• Verify brake engagement when power is removed.
• Confirm the brake does not drag during motor rotation.
• Record release and engagement behavior.

The published configuration specifies a 24 VDC brake, 1.29 A current draw, 53 ms connection time, and 97 ms disconnection time.

4. Feedback and Motor Testing

Use a compatible Rexroth drive/test system rather than applying uncontrolled power directly to the motor.

Verify:

• Phase-to-phase winding consistency.
• Insulation resistance using an appropriate motor test procedure.
• Drive recognition of the digital feedback device.
• Absolute multiturn position feedback.
• Encoder fault status.
• Correct motor direction.
• Controlled low-speed rotation.
• Phase/current balance.
• Abnormal vibration.
• Bearing noise.
• Temperature rise.

5. Controlled Load Test

Where test equipment permits, run the motor through a controlled load profile compatible with the applicable Rexroth drive and motor data.

Record:

• Initial temperature.
• Motor current.
• Feedback status.
• Brake status.
• Speed stability.
• Drive fault codes.
• Vibration.
• Temperature rise.
• Final encoder status.

6. Packaging and Shipping QA

This is a large approximately 55 kg motor, so packaging must prevent flange and shaft impact.

• Protect the 38 mm shaft from direct carton contact.
• Protect the feedback and power connectors.
• Prevent the motor from shifting during transport.
• Use ESD-conscious handling for feedback electronics.
• Protect the flange and centering pilot from impact.
• Document the motor nameplate before shipment.

 

Field Engineer’s Pitfall Guide

❗ PG1 is configuration-specific. Do not treat every -058 motor as electrically interchangeabl family includes PG0, PG1, NP, NG, and PP variants with different feedback configurations.

❗ BA means the motor includes a holding brake in this configuration. The published brake rating is 70 Nm at 24 VDC with a listed 1.29 A current draw. Confirm the machine’s brake-control circuit before commissioning.

❗ Do not use 70 Nm brake torque as a substitute for axis safety engineering. A brake is a holding component, not automatically a controlled stopping device for every machine condition.

❗ Do not confuse the 180 mm centering diameter with the 192 mm flange size. Both dimensions are required when checking mechanical compatibility.

❗ The shaft is plain, not keyed. The documented configuration uses a 38 mm plain shaft with an 80 mm extension. Verify the coupling or hub before approving a replacement.

❗ Cooling configuration matters. Sources for this exact model identify natural convection and surface cooling. Verify the machine’s mounting and thermal conditions rather than assuming that every installation has identical cooling performance.

❗ Do not copy generic speed or electrical-current values into a purchase specification. The exact motor/drive combination should be checked against Rexroth documentation and the motor nameplate before commissioning.

 

Intent-Driven FAQ

Q: What is the exact er for ?
A: The corresponding order number is R911290479.

Q: What is the continuous of the ?
A: The published continuous standstill torque is 70.0 Nm.

: Does the have a holding brake?
A: Yes. The BA configuration includes a 70 Nm holding brake. The published brake supply is 24 VDC with a 1.29 A current draw.

Q: What feedback does the PG1 version use?
A: PG1 uses digital servo feedback with an integrated encoder and absolute position detection exceeding 4,096 revolutions.

Q: What are the mounting dimensions?
A: The documented configuration has a 192 mm flange and 180 mm centering diameter.

Q: What shaft does this motor use?
A: It uses a 38 mm plain shaft with an 80 mm shaft extension and shaft seal.

Q: What is the protection rating?
A: The motor is specified at IP65.

A: Published configuration data identifies natural convection and surface cooling. The actual machine mounting and thermal conditions should be verified before installation.

Q: Is interchangeth another MHD115C motor?
A: Not automatically. Match the complete ordering code, winding 058, PG1 feedback, brake configuration, shaft dimensions, connector orientation, mounting dimensions, and compatible Rexroth drive parameters before approving a substitution.

Q: What condition should be specified when sourcing this legacy motor?
A: Unless the seller has provided inspection evidence, specify Legacy / Verify Condition and require nameplate photographs, serial identification, mechanical inspection, encoder verification, brake testing, and controlled motor testing before acceptance.