Cymotorix is a China-based AC servo motor manufacturer producing servo motors in 40mm to 180mm flange sizes, with rated power from 0.1kW to 7.5kW and rated speed of 2000–3000 rpm. Each motor carries an encoder and runs in closed loop with its matched servo drive, so this permanent-magnet (PM) servo motor holds position and speed under changing load and keeps torque across the full speed range, including high-speed operation. Common power ratings include 400W and 750W servo motor models in the smaller frames, scaling up to multi-kilowatt units. Rated torque spans roughly 0.32 N·m on the 40mm frame up to 47.7 N·m on the 180mm frame. Insulation is Class F, protection is IP65, and brake versions are available for vertical axes. As a China servo motor manufacturer, we supply the motor and drive as a tested set. The sections below break the range down by flange size.
AC servo motors in 40mm to 180mm flange sizes, rated power 0.1kW to 7.5kW, rated speed 2000–3000 rpm, built and tested in our own Changzhou plant as a direct servo motor manufacturer and servo motor supplier.
Every motor ships with an encoder and a matched servo drive, set up and tested as a closed-loop pair before delivery.
Shaft, flange, encoder type, brake, and lead/connector built to your drawing. Brake versions available for vertical axes.
Standard samples ship in 3–5 days. Custom prototypes in 10–15 working days. Selection questions answered within 24 hours.
We build three main types of stepper motors — 2-phase, 3-phase, and closed loop. The 2-phase hybrid is our highest-volume product, covering NEMA 8 through NEMA 42. If your application needs lower vibration at higher speeds, go with 3-phase. If you need position feedback and anti-lost-step protection, the closed loop series is the right fit.
| AC Servo | Closed Loop Stepper | Open Loop Stepper | |
|---|---|---|---|
| FEEDBACK | Encoder, continuous | Encoder | None |
| RATED SPEED | 2000–3000 rpm | Low–mid | Low–mid |
| RATED POWER | 0.1–7.5 kW | — | — |
| TORQUE AT SPEED | Held across range | Drops at speed | Drops at speed |
| BEST FOR | High speed, high dynamics | Anti-lost-step positioning | Low-cost positioning |
· Flange sizes 40mm, 60mm, 80mm, 110mm, 130mm, 180mm
· Rated power 0.1kW to 7.5kW, rated torque 0.32 N·m to 47.7 N·m
· 2500-line incremental or 17-bit absolute encoder
· IP65, Class F insulation, brake option for vertical axes
· Matched servo drive supplied and tuned with the motor
· Position, speed, and torque control modes
· Pulse/direction, RS485, CANopen, or EtherCAT options
· Electronic gear ratio, gain, and inertia settings adjustable
· Mechanical: shaft diameter and length, flange, keyway, lead exit direction
· Feedback: 2500-line incremental or 17-bit absolute encoder
· Add-ons: holding brake for vertical axes, planetary gearbox for low-speed high torque
· Branding: your logo on the motor body, custom labels and packaging
· Rotor: permanent magnet, low inertia for fast response
· Stator: wound for 220V (small/mid) or 380V (higher power)
· Encoder: 2500-line incremental or 17-bit absolute, rear-mounted
· Brake: optional power-off holding brake
Stepper motor and servo motor manufacturer in Changzhou, China since 2004. We run 5 production lines with annual output over 1,000,000 motors, serving OEM customers in 30+ countries.
About Us facility Solutions CertificationsAn AC servo motor is a permanent-magnet motor that runs under closed-loop control. An encoder on the shaft reports actual position and speed to the servo drive, which compares that against the command and adjusts current every cycle to correct any error. The result is a high-torque servo motor that holds torque across its full speed range, responds fast to load changes, and works as a high-speed servo motor that positions accurately at speed. Ours are rated 2000–3000 rpm, 0.1kW to 7.5kW, with Class F insulation and IP65 protection.
A servo uses continuous encoder feedback; a basic stepper runs open loop. That gives the servo higher top speed, better torque retention at speed, and faster dynamic response — the right choice for robotics, CNC spindles and feed axes, and high-speed handling. A stepper is cheaper, has strong holding torque at standstill, and positions well at low speed without feedback. If you need anti-lost-step reliability without full servo cost, look at the closed loop stepper motor; for low-cost positioning, the stepper motor range.
Flange sizes are 40mm, 60mm, 80mm, 110mm, 130mm, and 180mm. Rated power runs 0.1kW to 7.5kW, rated speed 2000–3000 rpm, and rated torque from about 0.32 N·m to 47.7 N·m depending on frame and length. Each flange size has its own page with the full model-by-model spec table.
Yes. Every servo motor ships with an encoder built in and a matched servo drive, sized and tuned as a set before delivery. Standard feedback is a 2500-line incremental encoder; a 17-bit absolute encoder is available when you need position memory through a power cycle without homing.
Yes. A power-off holding brake is available on any frame for vertical axes, so the load doesn't drop when power is cut. A planetary gearbox can be mounted for low-speed, high-torque, high-stiffness axes. Both are fitted and tested together with the motor before shipping.
Yes. Encoder type (incremental or absolute), shaft diameter and length, keyway, winding voltage, brake, and connector are all made to your drawing. We confirm feasibility within a day and build custom samples in 10–15 working days.
A working reference for engineers and procurement teams specifying industrial servo motors for OEM equipment. It covers how an AC servo works, how it differs from a stepper, the encoder and drive that come with it, and how to size one for an application.
An AC servo motor is a permanent-magnet motor wrapped in a closed-loop control system. The encoder on the shaft reports actual position and speed; the servo drive compares that against the command and trims current every control cycle to keep the rotor on track. Because the loop never stops correcting, the motor holds torque across its full speed range and snaps back from a load disturbance — unlike an open-loop stepper, whose torque falls off as speed rises and which can lose steps under overload. The low rotor inertia of a servo is what gives it the fast acceleration and high top speed that demanding motion needs.
This is the question most buyers start with when comparing types of servo motor against stepper drives. Both position accurately; the split is speed, dynamics, and cost.
| AC Servo | Stepper | |
|---|---|---|
| Control | Closed loop, always | Open loop (or closed with encoder) |
| Top speed | High (2000–3000 rpm) | Low to mid |
| Torque at speed | Held across range | Drops off |
| Holding torque at rest | Lower | High |
| Dynamic response | Fast | Moderate |
| Cost | Higher | Lower |
Use a servo when speed, throughput, or dynamic response leads. Use a stepper for steady, low-speed positioning on a budget. The middle ground — anti-lost-step reliability without full servo cost — is the closed loop stepper.
A servo motor is only half the system; the drive and encoder make it work. We supply all three matched. The encoder sets the feedback resolution: a 2500-line incremental encoder suits most positioning, while a 17-bit absolute encoder remembers position through a power cut, so the machine doesn't need to home on restart. The drive runs position, speed, or torque mode and connects by pulse/direction or by bus (RS485, CANopen, EtherCAT) depending on the model. Because we tune the pair before shipping, commutation, gain, and inertia matching are already set.
Flange size and power scale together. Pick the frame that delivers the torque your axis needs at its running speed:
Servo motor sizing comes down to four things, and getting them right is what keeps a servo from overheating or stalling:
Send us the load inertia, the move profile, and the axis speed, and our engineers confirm the frame, power, and drive before you order.
The speed and dynamic response make these motors a fit for robot joints, CNC machine-tool spindles and feed axes, high-speed handling and packaging lines, and AGV and automated-vehicle drives. Smaller frames (40–80mm) drive light, fast axes; larger frames (130–180mm) take the high-torque, high-power axes in machine tools and heavy automation.
