AC servo motor
Kollmorgen AKM2G AC servo motor
Second-generation AKM servo motor offering more torque per frame than the original AKM, in six IEC flange sizes, with standard and low-voltage windings and single-cable digital feedback options.
Key specifications
| Ingress protection | IP54 standard; IP65 with optional shaft seal |
|---|---|
| Peak torque (max) | 164 Nm |
| Continuous torque (max) | 72.8 Nm |
| Speed (max) | 8,000 rpm |
| Power (max) | 11,800 W |
| Frame sizes | 58, 72, 88, 114, 142, 192 mm |
| Supply | Standard windings for 120-480 Vac drives; low-voltage windings 24-96 V |
| Feedback | resolver, SFD3, SFD-M (battery-free multi-turn, 24-bit), HIPERFACE DSL, EnDat 2.2, BiSS B / optical sine encoder, commutating encoder |
Summarised in our own words from Regal Rexnord Corporation's published data; series maxima, individual models vary. Last checked 2026-10-29. Source 1 · Source 2
Notes on this data
Product page quotes continuous stall torque 0.65-72.1 Nm; RevG catalog system tables give 72.8 Nm max (AKM2G-74P with AKD 240 V) - catalog figure used. Peak 164 Nm (AKM2G-74P/74Q with AKD-x04807). Max mechanical speed 8000 rpm for 2x/3x frames, 6000 rpm for 4x-7x. 11.8 kW is AKM2G-74R at 400 V. Catalog lists connector IP65; overall motor IP from product page.
Specify Motion is not affiliated with Regal Rexnord Corporation. Kollmorgen and AKM2G are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Kollmorgen AKM2G model codes
Published model codes in the AKM2G range, with key figures from the manufacturer's data. Search this page for your part number, or send it to us for availability or an equivalent.
| Model code | Continuous torque, 120 V system (Nm) | Peak torque, 120 V system (Nm) |
|---|---|---|
| AKM2G-21D | 0.641 | 2.5 |
| AKM2G-21E | 0.645 | 2.53 |
| AKM2G-21G | 0.652 | 2.56 |
| AKM2G-22C | 1.12 | 4.11 |
| AKM2G-22D | 1.12 | 4.16 |
| AKM2G-22E | 1.12 | 4.39 |
| AKM2G-23D | 1.5 | 5.85 |
| AKM2G-23E | 1.5 | 5.84 |
| AKM2G-23F | 1.52 | 5.94 |
| AKM2G-24D | 1.82 | 7.13 |
| AKM2G-24E | 1.83 | 7.16 |
| AKM2G-24F | 1.86 | 7.24 |
| AKM2G-31C | 1.68 | 4.54 |
| AKM2G-31D | 1.69 | 6.01 |
| AKM2G-31E | 1.72 | 6.06 |
| AKM2G-32E | 2.83 | 10.3 |
| AKM2G-32G | 2.93 | 10.6 |
| AKM2G-33G | 3.84 | 14.4 |
| AKM2G-33H | 3.89 | 14.6 |
| AKM2G-41D | 2.87 | 7.2 |
| AKM2G-41E | 2.89 | 7.26 |
| AKM2G-41G | 2.89 | 7.25 |
| AKM2G-42H | 5.17 | 14.4 |
| AKM2G-43I | 7.07 | 21.1 |
| AKM2G-44H | 8.59 | 27 |
| AKM2G-44J | 8.59 | 26.9 |
| AKM2G-51H | 6.86 | 15.7 |
| AKM2G-51I | 6.88 | 15.7 |
| AKM2G-51K | 6.89 | 15.6 |
| AKM2G-52K | 12.1 | 28.9 |
| AKM2G-52L | 12.1 | 28.9 |
| AKM2G-53L | 16.3 | 41.4 |
| AKM2G-53M | 16.2 | 41.5 |
| AKM2G-54M | 20.3 | 54.7 |
| AKM2G-54N | 20.3 | 53.9 |
| AKM2G-62L | 15.4 | 37.4 |
| AKM2G-62M | 15.3 | 37.4 |
| AKM2G-63M | 21.6 | 54.5 |
| AKM2G-63N | 21.6 | 52.5 |
| AKM2G-64N | 27.2 | 64.8 |
| AKM2G-71N | 23 | 49.3 |
| AKM2G-71P | 23.3 | 46.4 |
Typical applications
Engineer support
Speak to our engineers about your project
Our experienced engineers are on hand, ready to help with your project. Whether you need the Kollmorgen AKM2G itself, help sourcing it, or a modified or custom design built around your load, speed and space, tell us what the machine has to do and we'll come back with the right option.
- Help sourcing AKM2G and spares for installed machines
- Modified and custom designs when a catalogue part doesn't fit
- Complete axis: motor, drive, gearing and feedback matched together
What an AC servo motor is
An AC servo motor is a permanent-magnet synchronous motor designed for closed-loop control of position, speed and torque. A wound stator is driven by a servo drive with sinusoidal three-phase current, while magnets on the rotor follow the rotating field. A high-resolution encoder or resolver on the shaft feeds position back to the drive, which adjusts current many thousands of times a second. The result is precise, dynamic motion with high peak torque, typically about three times the continuous rating for short periods.
When engineers choose an AC servo motor
Choose an AC servo for machine axes needing fast, accurate motion under varying loads, such as packaging, robotics, machine tools and printing. Compared with steppers, servos keep torque at high speed and cannot silently lose position. The trade-offs are cost and set-up: a servo needs a matched drive, feedback and tuning. For simple, low-speed indexing with a steady load, a stepper may be cheaper. For very low speeds and high torque, a gearbox or direct-drive motor may be needed.
How to specify the Kollmorgen AKM2G
Send these with your enquiry and an engineer can confirm the right AKM2G variant or an equivalent:
- Continuous and peak torque (Nm)
- Rated and maximum speed (rpm)
- Load inertia and inertia ratio
- Supply voltage: 230 V single-phase or 400 V three-phase
- Feedback: incremental or absolute encoder, resolution (bits)
- Holding brake, IP code and shaft options
- Flange size and mounting (mm)
Common mistakes to avoid
- Sizing on peak torque without checking RMS torque over the cycle
- Ignoring load-to-motor inertia ratio, which makes tuning hard
- Forgetting the brake is for holding, not dynamic stopping
- Using a motor and drive pair that the supplier has not matched
Kollmorgen AKM2G: frequently asked questions
What is the Kollmorgen AKM2G?
Second-generation AKM servo motor offering more torque per frame than the original AKM, in six IEC flange sizes, with standard and low-voltage windings and single-cable digital feedback options. Published series figures include peak torque 164 Nm, continuous torque 72.8 Nm, speed 8,000 rpm, power 11,800 W. It is made by Regal Rexnord Corporation; Specify Motion can help source it or propose an equivalent.
Who makes the Kollmorgen AKM2G?
The Kollmorgen AKM2G is made by Kollmorgen (Regal Rexnord Corporation) and is listed here for engineers comparing options. Specify Motion is not affiliated with Regal Rexnord Corporation; brand names are used only to identify the product.
What model codes are in the Kollmorgen AKM2G range?
The AKM2G range includes AKM2G-21D, AKM2G-21E, AKM2G-21G, AKM2G-22C, AKM2G-22D, AKM2G-22E, AKM2G-23D, AKM2G-23E and 34 more. The table on this page lists each published model code with its key figures. Send us the code you use, or the one you need to replace, and our engineers will confirm availability, lead time or the closest equivalent.
What is the peak torque of the Kollmorgen AKM2G?
The published series maximum peak torque is 164 Nm. Individual models and sizes in the AKM2G range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
Is there an alternative to the Kollmorgen AKM2G?
Yes. Our engineers can propose an equivalent built around your load, speed and environment. An engineer confirms the fit against your application before recommending anything.
What is the inertia ratio in servo sizing?
The inertia ratio compares the load inertia reflected to the motor shaft with the motor's rotor inertia. High ratios make the axis harder to tune and slower to settle. Many engineers aim for below about 10:1, and lower for highly dynamic axes, using a gearbox to reduce reflected inertia where needed.
Do AC servo motors need an absolute encoder?
Not always. Incremental encoders need a homing routine after power-up, which is acceptable on many machines. Absolute encoders know their position at power-on, avoiding homing, which saves time and suits robots and multi-axis machines. Multi-turn absolute encoders track turns even when power is off.
Further reading: How to select a servo motor · Servo vs stepper · Servo and stepper motors
Other ac servo motor series
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Engineer support
Our engineers are ready to help with your project
Tell us about your project and how you use the Kollmorgen AKM2G: the load, speed, duty and environment. An experienced engineer will review it and reply, normally within one working day.
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