AC servo drive
Kollmorgen AKD AC servo drive
Single-axis servo drive family covering 120/240 V and 240/480 V supplies, with broad feedback compatibility and a choice of industrial Ethernet and CAN fieldbuses.
Key specifications
| Power (max) | 32,000 W |
|---|---|
| Supply | 120/240 Vac 1/3-phase (85-265 V) or 240/480 Vac 3-phase (187-528 V); 24 V logic |
| Feedback | Smart Feedback Device, EnDat 2.1/2.2, BiSS, sine/cosine encoder, incremental encoder, HIPERFACE, resolver |
| Fieldbus | EtherCAT, EtherNet/IP, PROFINET RT, Modbus/TCP, CANopen, SynqNet |
| Axes | 1 |
| Continuous current (max) | 48 A |
| Peak current (max) | 96 A |
Summarised in our own words from Regal Rexnord Corporation's published data; series maxima, individual models vary. Last checked 2026-10-29. Source 1
Notes on this data
Current range 3-48 A rms continuous, 9-96 A peak (5 s); 48 A model (AKD-x04807) 480 V only. Page does not state lifecycle status; AKD2G is the newer generation. Sercos appears only in document list, not included.
Specify Motion is not affiliated with Regal Rexnord Corporation. Kollmorgen and AKD are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Typical applications
Alternatives that meet or exceed these figures
Engineers often come to us with a Kollmorgen part number and leave with an alternative that is easier to source, quicker to deliver or a better fit for the machine. These 3 series from our supply network are the closest match on published figures.
Network-capable AMC digital drives spanning 10-747 VDC and 120-480 VAC, up to 150 A continuous and 250 A peak (27.4 kW peak power), in PCB, panel, machine and vehicle formats. They support almost any motor type and feedback, plus CANopen, EtherCAT, POWERLINK and Modbus.
| Published maximum | AKD | DigiFlex Performance Servo Drives (DP,… |
|---|---|---|
| Continuous current | 48 A | 150 A meets or exceeds |
| Peak current | 96 A | 250 A meets or exceeds |
| Power | 32,000 W | 27,400 W |
| Axes | 1 | — |
Leadshine's high-end 220 VAC servo drive from 400 W to 2 kW with 3.5 kHz bandwidth, STO SIL3, dual-encoder full closed-loop control and gantry synchronisation. EC models run EtherCAT; RS models offer Modbus RTU, pulse+direction and analogue.
| Published maximum | AKD | EL8 Series AC Servo Drives (EL8-EC / E… |
|---|---|---|
| Continuous current | 48 A | 12 A |
| Peak current | 96 A | 36 A |
| Power | 32,000 W | 2,000 W |
| Axes | 1 | 1 meets or exceeds |
Leadshine's EL7 platform spans 220 VAC drives from 400 W to 2 kW, 400 VAC drives to 7.5 kW and an 11-22 kW high-power range, all with STO and EtherCAT, Modbus/pulse or PROFINET variants.
| Published maximum | AKD | EL7S / EL7 Series AC Servo Drives |
|---|---|---|
| Continuous current | 48 A | 44 A |
| Peak current | 96 A | 88 A |
| Power | 32,000 W | 22,000 W |
| Axes | 1 | 1 meets or exceeds |
Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.
What an AC servo drive is
An AC servo drive, or servo amplifier, powers and controls a servo motor from mains supply. It rectifies the AC input to a DC bus, then uses an inverter of power transistors switched by PWM to produce controlled three-phase current in the motor. Nested current, velocity and position loops use encoder feedback to follow commands from pulse and direction, analogue or industrial Ethernet. Modern drives add auto-tuning, vibration suppression and safety functions such as safe torque off.
When engineers choose an AC servo drive
Choose an AC servo drive for mains-powered machines with servo axes from tens of watts to many kilowatts, such as packaging, machine tools and robotics. It gives precise, dynamic control with standard industrial interfaces. The trade-offs are cabinet space, wiring, EMC measures and the need to match motor and feedback. For low-voltage or mobile machines, a DC drive is more suitable; for many axes in one cabinet, a multi-axis drive may save space.
How to specify the Kollmorgen AKD
Send these with your enquiry and an engineer can confirm the right AKD variant or an equivalent:
- Supply voltage and phases (V AC)
- Continuous and peak output current (A rms)
- Motor and feedback compatibility
- Command interface: pulse, analogue, EtherCAT, PROFINET and so on
- Safety functions, such as STO, and their rating (SIL, PL)
- Braking resistor and regenerative energy (W, J)
- Ambient temperature, mounting and cooling
Common mistakes to avoid
- Sizing on motor rated current without the drive's peak duration
- Ignoring regenerative energy on fast decelerations or vertical axes
- Leaving out EMC filtering and screened motor cables
- Mixing motor and encoder types the drive does not support
Kollmorgen AKD: frequently asked questions
What is the Kollmorgen AKD?
Single-axis servo drive family covering 120/240 V and 240/480 V supplies, with broad feedback compatibility and a choice of industrial Ethernet and CAN fieldbuses. Published series figures include power 32,000 W, axes 1, continuous current 48 A, peak current 96 A. It is made by Regal Rexnord Corporation; Specify Motion can help source it or propose an equivalent.
Who makes the Kollmorgen AKD?
The Kollmorgen AKD 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 is the power of the Kollmorgen AKD?
The published series maximum power is 32,000 W. Individual models and sizes in the AKD 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 AKD?
Yes. On published figures, ADVANCED Motion Controls DigiFlex Performance Servo Drives (DP, DZ, DV) and Leadshine EL8 Series AC Servo Drives (EL8-EC / EL8-RS) are the closest match from our supply network. An engineer confirms the fit against your application before recommending anything.
Does a servo drive need a braking resistor?
When a servo motor decelerates, it acts as a generator and returns energy to the drive's DC bus. If the bus capacitors cannot absorb it, the voltage rises and the drive trips. A braking resistor dissipates the energy as heat. Fast decelerations, high inertia and vertical axes usually need one.
What is safe torque off on a servo drive?
Safe torque off, or STO, is a safety function that removes power that could produce torque at the motor, without disconnecting the drive supply. It is defined in IEC 61800-5-2 and used as part of a machine's safety system. Check the safety level achieved and wiring requirements.
Further reading: How to select a servo drive · How to select a servo motor · Servo drives
Other ac servo drive series
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