Bosch Rexroth MKD041B-144-KG1-KN | Servo Motor

Description

Bosch Rexroth MKD041B-144-KG1-KN | Servo Motor

 

Product Introduction

The Bosch Rexroth Indramat MKD041B-144-KG1-KN is an MKD-series permanent-magnet synchronous servo motor designed for closed-loop machine motion systems using compatible Rexroth Indramat drive platforms. The 041B frame uses the 144 winding and a resolver feedback system with integrated multiturn absolute position detection. The KG1 configuration specifies a plain shaft and integrated 2.2 Nm holding brake, while the KN suffix identifies the standard housing/connection configuration.

For drive replacement and legacy-axis maintenance, the electrical and mechanical details matter as much as the frame size. This motor is rated at 0.52 kW and 3,000 RPM, with 2.7 Nm continuous standstill torque, a 6,000 RPM characteristic speed, and 7,500 RPM maximum speed. The resolver/encoder feedback, 82 mm flange, 50 mm centering diameter, and 2.2 Nm brake must match the existing drive and machine configuration before installation.

Key Technical Specifications

• Manufacturer: Bosch Rexroth Indramat
• Model: MKD041B-144-KG1-KN
• Order/Material Number: R911260465
• Motor Series: MKD Synchronous Motors
• Motor Size: 041
• Motor Length: B
• Winding Code: 144
• Rated Power: 0.52 kW
• Rated Speed: 3,000 RPM
• Characteristic Motor Speed: 6,000 RPM
• Maximum Speed: 7,500 RPM
• Continuous Standstill Torque: 2.7 Nm at natural cooling / 60 K
• Continuous Standstill Current: 7.5 A at natural cooling / 60 K
• Peak Current: 34 A
• Rated Current: 2.8 A
• Rated Voltage: 115 V
• Rated Frequency: 150 Hz
• Torque Constant: 0.4 Nm/A
• Winding Resistance: 1.8 ohms at 20°C
• Winding Inductance: 5 mH
• Pole Pairs: 3
• Rotor Inertia: 1.7 × 10⁻⁴ kg·m²
• Theoretical Maximum Torque: 11.3 Nm
• Feedback: Resolver with integrated multiturn absolute encoder
• Position Detection: Absolute, greater than 4,096 revolutions
• Shaft: Plain shaft with shaft sealing ring
• Holding Brake: 2.2 Nm
• Brake Voltage: 24 VDC ±10%
• Brake Current: 0.34 A
• Brake Connection Time: Approximately 14 ms
• Brake Disconnection Time: Approximately 28 ms
• Flange Size: 82 mm
• Centering Diameter: 50 mm
• Connection: Junction box, power connection directed toward side B
• Protection Rating: IP65
• Insulation Class: F
• Permissible Ambient Temperature: 0°C to +40°C
• Storage/Transport Temperature: -20°C to +80°C
• Maximum Setup Height: 1,000 m above sea level
• Motor Mass: Approximately 4.4 kg

 

Application Scenarios & Pain Points

1. Legacy Rexroth Servo Axis Replacement

Used when an existing Indramat MKD041B motor must be replaced without redesigning the complete mechanical axis.

Engineering pain point: A visually similar MKD041B motor can have a different feedback, shaft, brake, or winding configuration. The complete type code must match.

2. Machine Tool Feed and Positioning Axes

The 3,000 RPM rated operating point and 2.7 Nm continuous standstill torque support compact positioning and feed applications.

Engineering pain point: Substituting a motor solely by torque or flange dimensions can produce encoder incompatibility or incorrect drive parameterization.

3. Packaging and Material-Handling Machinery

The integrated multiturn absolute feedback is applicable to servo axes where the control architecture requires absolute position information over multiple revolutions.

Engineering pain point: The replacement drive must recognize the resolver/encoder configuration. A standard resolver-only motor is not automatically equivalent to the KG1 configuration.

4. Vertical or Gravity-Loaded Axes

The integrated 2.2 Nm holding brake provides mechanical load retention when the motor is de-energized.

Engineering pain point: The brake is a holding device, not a dynamic stopping brake. Confirm the machine’s stopping and safety architecture before relying on it for motion control.

5. Obsolete-System Maintenance Stock

The MKD041B-144-KG1-KN is relevant for maintenance departments supporting legacy Indramat-controlled production equipment.

Engineering pain point: Long downtime can result when a complete motor/feedback/brake combination is unavailable. Pre-verifying the nameplate and drive compatibility reduces replacement errors.

 

QA & Live Testing SOP

1. Identity Verification

• Photograph and verify the complete MKD041B-144-KG1-KN nameplate.
• Confirm material/order number R911260465 where present.
• Verify the 144 winding designation.
• Confirm the motor is the KG1 configuration rather than KG0, KP0, or KP1.

2. Mechanical Inspection

• Inspect the 82 mm flange and 50 mm centering pilot.
• Check the plain shaft for scoring, corrosion, impact damage, and excessive radial play.
• Inspect the shaft sealing ring.
• Rotate the rotor manually and check for abnormal bearing noise or mechanical drag.

3. Brake Test

• Apply the specified 24 VDC brake supply using a controlled test setup.
• Verify brake release and engagement.
• Measure brake current and compare against the expected approximately 0.34 A value.
• Confirm the brake does not remain partially energized.
• Never use the holding brake as a substitute for a controlled dynamic stop.

4. Winding Test

• Measure phase-to-phase resistance and compare the three phases for balance.
• Perform appropriate insulation-resistance testing with test voltage selected according to the motor and test-equipment procedure.
• Check for phase-to-frame insulation faults.
• Do not apply uncontrolled high-voltage testing to encoder circuitry.

5. Feedback Test

• Verify resolver wiring and connector condition.
• Connect the motor only to a compatible Rexroth/Indramat test drive.
• Confirm resolver feedback is detected correctly.
• Verify absolute/multiturn position behavior through the compatible drive system.

6. Controlled Rotation Test

• Use current-limited startup conditions.
• Verify correct phase sequence and feedback polarity through the drive.
• Check low-speed rotation before increasing speed.
• Monitor current, following error, vibration, and abnormal bearing noise.
• Do not approach the 7,500 RPM maximum speed during a basic incoming inspection unless the complete test fixture and safety enclosure are specifically rated for it.

7. Packaging and ESD Control

• Protect resolver/encoder connectors from impact and contamination.
• Use ESD-safe handling for feedback-related components.
• Protect the shaft and flange during transport.
• Use rigid packaging capable of preventing rotor/shaft impact.
• Record serial number, nameplate photographs, inspection results, and test measurements for traceability.

 

Field Engineer’s Pitfall Guide

❗ Do not substitute by frame size alone.
The -144 family contains multiple feedback, shaft, brake, and connection variants. The KG1 configuration combines the multiturn resolver/encoder feedback with a plain shaft and 2.2 Nm holding brake.

❗ Do not confuse rated, characteristic, and maximum speed.
The documented values are 3,000 RPM rated speed, 6,000 RPM characteristic speed, and 7,500 RPM maximum speed. These are not interchangeable operating specifications.

❗ Check the brake before installing on a vertical axis.
The 2.2 Nm brake is a holding brake. Verify the actual static load torque and safety requirements rather than assuming the brake can stop a moving load.

❗ Resolver compatibility must be confirmed at the drive.
The KG configuration uses resolver feedback with integrated multiturn absolute position detection. A motor with a superficially similar -144 designation can have a different feedback configuration.

❗ Verify the complete type code before a drop-in replacement.
For example, KG1-KN should not be casually replaced with KP1-KN, because the shaft configuration differs even though both versions have a 2.2 Nm holding brake.

 

Intent-Driven FAQ

What is the Bosch R-KG1-KN?

The is a Bosch Rexroth Indramat MKD permanent-magnet synchronous AC servo motor with a 144 winding, multiturn resolver/encoder feedback, plain shaft, and integrated 2.2 Nm holding brake.

What iof the ?

The documented natural-cooling rating is 0.52 kW at 3,000 RPM, with a rated voltage of 115 V and rated current of 2.8 A.

What is the maximum speed?

The documented maximum speed is 7,500 RPM. The characteristic motor speed is 6,000 RPM, while the rated speed is 3,000 RPM.

Does the have a holding brake?

Yes. The KG1 configuration includes a 2.2 Nm holding brake operating from approximately 24 VDC with a rated current of 0.34 A.

Does this motor have a keyed shaft?

No. The KG1 configuration uses a plain shaft with a shaft sealing ring. A KP1 version uses a keyed shaft and should not be assumed mechanically interchangeable.

es the use?

It uses resolver feedback with an integrated multiturn absolute encoder, providing absolute position detection over more than 4,096 revolutions within the compatible control architecture.

What are the mounting dimensions?

The motor uses an 82 mm flange with a 50 mm centering diameter. Verify the complete mechanical interface, shaft dimensions, and connector orientation before installation.

Is the still a current-production motor?

The family is a legacy Rexroth Indramat product line. For replacement procurement, verify actual unit condition, nameplate identity, serial number, and available test documentation rather than assuming a used or surplus unit is equivalent to a factory-new motor.

What should be checked before ordering a replacement?

Provide the supplier with the complete existing motor type code and nameplate photograph. Confirm , winding 144, feedback type, plain shaft, holding brake, flange/centering dimensions, connector configuration, and compatibility with the installed Rexroth drive.