A servo motor is a brushless motor with a built-in feedback device that reports shaft position back to the drive, which is what allows an axis to hold a setpoint, index to a fixed distance and stay synchronized with the rest of the machine. Motors fail from bearing wear, cable damage, encoder faults and overheating, and a replacement has to match both the mechanics and the drive configuration. MT.parts keeps 130+ servo motors in stock from the leading motion control brands, including units that are discontinued or no longer sold by the manufacturer.
Where these motors are used
- CNC machine tools, on feed axes, turrets and tool changers where repeatability defines part quality.
- Packaging and filling lines, on rotary knives, augers, star wheels and indexing conveyors.
- Gantries, cartesian robots and pick and place cells, often with holding brakes on vertical axes.
- Printing, labeling and web converting, driving unwind, nip and rewind sections in registration.
- Assembly and test stations, on press-fit, screwdriving and dispensing heads under torque control.
- Food, beverage and pharma equipment, where washdown-rated motors and stainless shafts are common.
How to choose a replacement servo motor
The motor is only half of the axis. It has to fit the machine and match the drive already in the cabinet:
- Part number first. The full catalog string encodes frame size, winding, feedback, shaft, brake and connectors. Search it in our catalog.
- Frame size, continuous torque and rated speed, plus rotor inertia, which drives tuning and load matching.
- Feedback device, incremental encoder, single-turn or multi-turn absolute encoder, or resolver. The drive has to recognize it, and multi-turn absolute motors keep homing after a power cycle.
- Holding brake, normally 24 VDC, mandatory on vertical and cantilevered axes so the load does not drop when the drive is disabled.
- Shaft and mounting, keyed versus smooth shaft, shaft diameter, flange dimensions and bolt pattern, since even the same torque rating can come in different mechanical builds.
- Connectors and cables, straight versus rotatable connectors, power and feedback cable series, motor voltage rating (for example 230 V versus 460 V windings) and the IP rating for washdown areas.
If you are unsure which code replaces yours, send us the nameplate data and our team identifies the correct unit.
New, refurbished and obsolete servo motors
We supply three conditions, and the condition is always stated on the product page. New units are factory-sealed. Refurbished units are inspected, repaired where needed and functionally tested before shipping. Obsolete and hard-to-find motors are models the manufacturer has discontinued, which is often the only way to keep an older machine running without changing the drive, the cables and the mounting at the same time. Every motor we ship carries a 12-month warranty.
Servo motor brands and series we stock
- Allen-Bradley: Kinetix MP-Series servo motors
- Fanuc: servo motors for machine tool axes, listed by model code
- Siemens: servo motors listed by order number
- Omron: servo motors listed by model code
The catalog also lists BSM series servo motors by part number.
Frequently asked questions
How is a servo motor different from a servo drive and from a VFD motor setup?
The servo motor is the machine-mounted motor with an integrated feedback device. The servo drive is the cabinet electronics that powers it and closes the control loop, and the two are commissioned as a matched pair. A variable frequency drive instead runs a standard AC induction motor with no feedback device on most installations, which is fine for pumps, fans and conveyors but cannot hold position. If you are replacing an axis, confirm which of the three parts actually failed before ordering.
Can I replace a discontinued servo motor with a newer model?
Sometimes, but newer motor families often change the flange, the shaft, the feedback protocol and the connector style, so the drive, the cables and the mechanical coupling can all have to change with the motor. Replacing with the same discontinued catalog number keeps the axis as built. We stock obsolete motors for exactly that reason.
Do refurbished servo motors come with a warranty?
Yes. New, refurbished and obsolete motors all ship with a 12-month warranty.
How fast can I get a quote?
We reply to quote requests within 24 hours, including part identification when you only have nameplate data.
Do you ship internationally?
Yes. We ship worldwide, including to plants outside the United States.
Can't find your part number?
If the servo motor you need is not listed, we source it. Send us the manufacturer, part number and quantity, and our team locates the unit, including discontinued models. Request a quote.
