Cymotorix, a China-based motor and accessories manufacturer and supplier, provides the accessories that mount directly onto our motors — planetary gearboxes, encoders, and electromagnetic brakes. You can order any of them on their own to fit your existing motor, or have us assemble and test the part on a Cymotorix motor so it ships as one unit. Gearboxes cover NEMA 17 frames up to 180mm flanges, with reduction ratios from 3 to 216 and rated torque up to 360 N·m. Encoders come in 2500-line incremental and 17-bit absolute types. Brakes are power-off type for vertical-axis hold. The sections below cover each accessory and how to match it to a motor.
Planetary gearboxes, encoders, and electromagnetic brakes that mount directly onto our stepper and servo motors.
Order a part on its own, or have us fit and test it on the motor as one assembled unit before shipping.
Gearboxes from NEMA 17 frames up to 180mm flanges, encoders in incremental and absolute types, brakes for vertical-axis hold.
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.
| Accessory | What It Does | Fits | Key Spec |
|---|---|---|---|
| Planetary Gearbox | Raises torque, lowers speed, adds precision | NEMA 17–51 / 60–180mm | Ratio 3–216, torque to 360 N·m |
| Encoder | Position / speed feedback | Closed-loop steppers, servos | 2500-line incremental / 17-bit absolute |
| Electromagnetic Brake | Power-off hold, anti-drop on vertical axes | Steppers and servos | 24V power-off type |
· Reduction ratio 3:1 to 216:1 (1–3 stages)
· Rated torque 6 N·m to 360 N·m
· Backlash from ≤15 arcmin, efficiency up to 95%
· IP65, grease-lubricated, ~20,000 h service life
· 2500-line incremental encoder (standard)
· 17-bit absolute encoder for position memory
· Rear-shaft mounted, sealed against dust
· Used on closed loop steppers and AC servos
· Power-off (spring-applied) holding brake, 24V
· Fail-safe: holds on power loss or e-stop
· For vertical axes and hanging loads
· Fitted on steppers and servos to your spec
· Gearbox, encoder, or brake fitted and tested on the motor
· Custom shaft, flange, or mounting to match your gearbox
· Mixed assemblies (e.g. motor + gearbox + brake) on request
· Wiring diagram and pinout shipped with the unit
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 CertificationsWe supply three accessories that mount directly onto our motors: planetary gearboxes (raise torque, lower speed, add precision), encoders (position and speed feedback for closed-loop control), and electromagnetic brakes (power-off hold for vertical axes). All three are made to fit our stepper and servo frames, and can be ordered loose or assembled onto the motor.
Yes. Any accessory can be ordered on its own to fit a motor you already have — tell us the motor's frame size and shaft, and we'll confirm the matching gearbox, encoder, or brake. You can also buy it pre-assembled and tested on a Cymotorix motor as one unit, which removes the fitting and alignment work on your end.
Three things decide the match: frame size (the gearbox flange has to match the motor's mounting), reduction ratio (set by the torque and speed your axis needs — higher ratio gives more torque and lower speed), and backlash (lower backlash for tighter positioning). Our range covers ratios from 3:1 to 216:1 and torque to 360 N·m. Send us the motor and the load and we'll size it. Full data is on the planetary gearbox page.
An incremental encoder counts position changes from a reference point, so the system has to home on power-up to know where it is. An absolute encoder reports the exact shaft angle at all times, including right after a power cut, so no homing is needed. We fit 2500-line incremental as standard and 17-bit absolute when the application can't afford a homing routine or a lost reference.
Use an electromagnetic brake on any axis where the load must stay put when power is cut — vertical axes, lifts, hanging arms. A power-off brake clamps the shaft when de-energized, so the load holds on e-stop or power loss instead of dropping. On a horizontal axis with no back-drive risk, you usually don't need one.
Yes, and it's the option we recommend for most customers. We fit the gearbox, encoder, or brake onto the motor, align it, and test the assembly as a complete drive before it ships. That saves you the assembly time and removes the alignment and compatibility risk of pairing parts yourself. Mixed builds — motor plus gearbox plus brake — are available too.
A working reference for engineers and procurement teams adding a gearbox, encoder, or brake to a stepper or servo motor. It covers what each accessory does, how to match it to the motor, and when you actually need one.
A planetary gearbox is the accessory that changes a motor's output the most. Mounted on the motor shaft, it multiplies torque by the reduction ratio and divides speed by the same number — a 10:1 gearbox gives roughly ten times the torque at one-tenth the speed. It also improves positioning resolution, since one output degree now takes several motor revolutions. Our gearboxes run ratios from 3:1 to 216:1 in one-, two-, and three-stage builds, with rated torque from 6 N·m on the smallest frame to 360 N·m on the largest, backlash from ≤15 arcmin, and IP65 sealing. Use one when the motor alone can't deliver the torque, when the load needs to run slower than the motor's efficient speed, or when you want finer positioning. The full model-by-model range is on the planetary gearbox page.
An encoder turns an open-loop motor into a closed-loop one by reporting rotor position and speed back to the drive. That's what lets a closed loop stepper correct lost steps and what makes a servo a servo. The choice is between two types:
Resolution should be matched to the positioning accuracy the application needs, not pushed higher than necessary.
An electromagnetic holding brake keeps the shaft locked when power is off. Ours are power-off (spring-applied) type: the brake clamps when de-energized and releases when powered. That fail-safe behaviour is what a vertical axis needs — if power drops or the machine hits e-stop, a hanging load stays put instead of falling. A brake is worth fitting on lifts, vertical Z-axes, and hanging arms; on a horizontal axis with no back-drive risk it's usually unnecessary. We fit the brake between the motor body and the rear encoder, so it doesn't change the mounting.
Most decisions come down to the load and the axis:
These combine — a vertical CNC axis might use a motor with a gearbox for torque, an encoder for feedback, and a brake for hold, all on one frame. We assemble and test the full stack before shipping. Send us the motor model or the application and our engineers confirm the right accessories and whether to ship them loose or pre-assembled.
