Description
REXROTH Servo Motor MSK040C-0450-NN-M1-UG1-NNNN — Full Introduction
This is a IndraDyn S series synchronous servo motor from Bosch Rexroth (Germany), belonging to the MSK sub-series. It is designed for high-precision, high-dynamic-response industrial automation applications. Below is a detailed breakdown of every aspect of this motor.
1. Model Code Decoding
The model number follows Rexroth’s standard naming convention. Each segment carries specific meaning:
MSK — IndraDyn S series synchronous servo motor family.
040 — Frame size (flange dimension). This is a compact, small-to-medium frame, ideal for space-constrained installations.
C — Motor length code. “C” indicates a medium-length version in the 040 frame — longer than “B” but shorter than “D”.
0450 — Rated speed of 4,500 rpm.
NN — Cooling method: natural convection (no external fan, no liquid cooling). Simple and maintenance-free.
M1 — Encoder type: EnDat 2.2 absolute multi-turn encoder. This is a high-precision feedback device that retains position data even after power loss — no homing required on restart.
UG1 — Electrical connection: rotatable plug connector (240°). The “G1” suffix means no holding brake (no抱闸). The motor shaft will freewheel when power is removed.
NNNN — Standard design, no special customization.
Rexroth Servomotor MSK040C-0450-NN-M1-UG1-NNNN R911320224
2. Core Technical Parameters
Based on the MSK040C series specifications and the 0450 speed variant, the typical performance data for this motor is as follows:
Rated speed: 4,500 rpm (as specified in the model code)
Maximum speed: Up to 9,000 rpm (MSK series general limit)
Rated torque (continuous, standstill): Approximately 4.0 Nm
Maximum torque (peak, short-term): Approximately 8.1 Nm
Rated current (continuous): Approximately 4.7 A
Peak current: Approximately 12.4 A
Torque constant (Kt): Approximately 0.95 Nm/A
Voltage constant (Ke): Approximately 58.2 V/(1000 rpm)
Rotor inertia: Approximately 0.00014 kg·m² — extremely low, enabling very fast acceleration and deceleration
Thermal time constant: Approximately 16 minutes
Protection class: IP65 — fully protected against dust and low-pressure water jets. Suitable for harsh industrial environments with coolant spray, oil mist, etc.
Insulation class: F class (155°C)
Weight: Approximately 3.9 kg (motor body only, no brake — because UG1 = no holding brake)
Important note: Since UG1 indicates no holding brake, the motor shaft is free to rotate when de-energized. This makes it ideal for horizontal axis applications or systems with external braking mechanisms. If you need a brake for vertical axes (e.g., Z-axis on a CNC machine), you should choose a model with UP1 instead.
3. Key Features and Advantages
High torque density, compact structure
The MSK series is Rexroth’s flagship servo motor line, with torque ranging from fractions of an Nm up to 495 Nm — all in very compact packages. The 040 frame is perfect for small CNC machine feed axes, robot joints, pick-and-place systems, and other space-limited applications.
Ultra-high precision encoder
The M1 encoder (EnDat 2.2, absolute multi-turn) delivers sub-micron level positioning accuracy. Because it is absolute and multi-turn, the drive always knows the exact shaft position — even after a complete power loss. This eliminates the need for reference homing every startup, saving cycle time and improving reliability.
Exceptional dynamic response
With a rotor inertia of just 0.00014 kg·m², this motor can accelerate and decelerate extremely quickly. It excels in applications requiring frequent start-stop cycles, rapid direction changes, and high-speed positioning.
IP65 rating — built for tough environments
The fully sealed design protects the motor from dust, chips, coolant, and oil mist. It is a natural fit for CNC machining centers, injection molding machines, and other demanding industrial settings.
Natural convection cooling — zero maintenance
No external fan, no liquid cooling loop. The motor dissipates heat through its own housing. This means fewer components, lower installation cost, and zero maintenance for the cooling system.
Optimized for IndraDrive Cs
The MSK series is co-engineered with Rexroth’s IndraDrive Cs compact servo drive, but it also works with other Rexroth drives (IndraDrive C, M, H series). It supports all major industrial communication protocols: PROFIBUS, PROFINET, EtherCAT, CANopen, and SERCOS III.
4. Typical Application Scenarios
CNC Machine Tools — Feed axis drives, turret indexing, spindle auxiliary drives. The 4,500 rpm rated speed and 4 Nm continuous torque are well-suited for small-to-medium CNC lathes and milling machines.
Industrial Robots — Joint actuation, palletizing robots, welding robots. The low inertia and high dynamic response enable smooth, fast robotic motion.
Printing and Packaging Machinery — Color registration roller drives, film tension control, label cutting axes.
Textile Machinery — Spinning spindle drives, loom main shafts.
Automated Production Lines — Material handling, precision assembly, inspection equipment, conveyor synchronization.
Electronics Manufacturing — Pick-and-place machines, semiconductor equipment, PCB drilling — anywhere sub-micron positioning is required.
5. Comparison with Similar Models in the Same Series
MSK040C-0450-NN-M1-UG1-NNNN (this model) — 4,500 rpm, EnDat absolute multi-turn, no brake. Best for horizontal axes needing high precision at moderate speed.
MSK040C-0600-NN-M1-UG1-NNNN — 6,000 rpm, same encoder, no brake. Higher top speed but slightly lower torque. Good for applications where speed matters more than torque.
MSK040C-0450-NN-M1-UP1-NNNN — 4,500 rpm, EnDat absolute multi-turn, with holding brake. The go-to choice for vertical axes (Z-axis) where the load must be held in position when power is off.
MSK040C-0450-NN-S1-UG1-NNNN — 4,500 rpm, HIPERFACE single-turn encoder, no brake. Lower cost option when multi-turn capability is not needed.
6. Summary
The MSK040C-0450-NN-M1-UG1-NNNN is a 4,500 rpm, medium-length, no-brake, EnDat 2.2 absolute multi-turn encoder, naturally cooled, IP65-rated high-performance synchronous servo motor from Bosch Rexroth.
It is an excellent choice for applications that demand high positioning accuracy, fast dynamic response, and reliable operation in harsh environments — but do not require extremely high speeds (4,500 rpm is more than sufficient for most feed-axis and robot-joint applications). Paired with a Rexroth IndraDrive Cs or IndraDrive C servo drive, it delivers smooth, precise, and highly repeatable motion control — making it one of the most widely used servo motors in modern industrial automation.
