Welcome to SD Servo Motors



General Data

S series of rare earth 3 phase permanent magnet servo motors was conceived and designed as an advanced and homogeneous range of high performance servo actuators, in line with the evolving demands of the automation industry, and is particularly suited for direct drive applications.

S series servo motors reach the highest torque/size and power/size rations in the industry. They are designed for sinusoidal control and embody, as standard feedback devices, inductive encoder, custom designed for motor operation, which offers resolution up to 4096p/rev thus affording the best motion uniformity even at the lowest speed. With this feature, the limits of mechanical transmissions are overcome and a vast range of applications can be transferred to direct drive technology.

S series servo motors have two frame bases: S18 series and S25 series, under S4 working situation, the rated power accordingly range from 4kw to 37kw and from 20kw to 85kw., Intended for direct, distributed drive of continuous process lines, in view of the progressive elimination of long transmission shafts. The rated speed has the range from 1000rpm to 3000rpm. S18 and S25 series’ windings are for 380/440Vac.

S25 Series Motor

S18 Series Motor

S25 Series


S18 Series


The Technical Characteristics Of The Servo Motor Qualification

Overall Performance

Low rotor inertia, fast response. High demagnetization resistance ability. Smooth and stable running in high speed, low noise.

Temperature Protection

PTC130 and KTY84
have a positive temperature coefficient of resistance and are suitable for use in measurement


High performance low loss silicon steel sheet W300. High performance rare earth magnets with latest surface assembly technology


Tamagawa BRX Smartsyn Encoder
with a wide temperature range and superior environment resistance

Motors Parameter

Rating torque: 29Nm-511NM.
Locked-rotor torque: 31Nm-550Nm.
Peak speed: Max speed is 3000rpm for standard motors.

Specifications Of Standard Models

  • Type


  • Rotor

    Sintered, high temperature rare earth, mechanically fastened magnets

  • Insulation

    Class F according to GB755-2008L / IEC 60034-1.2010

  • Thermal Protection

    PTC+KTY 84 Linear probe

  • Position Sensor

    Sine encoder4076p/rev, Operating temperature up to 155°C

  • Bearings

    Heavy duty, life lubricated; Sizes S18 and S25: front bearing locked in high strength steel.

  • Balancing

    Grade R (reduced tolerance)

  • Concentricity & Squareness Of Mounting Flange

    According GB/T 4772.1-1999 and IEC72-1:1991

  • Shaft

    Cylindrical had keyway, tolerance K6, axial threaded hole

  • Cooling Options

    GB755-2008L; Designed for process lines and sustained operation at high speed, option F, Forced cooling over frame with fan servo controlled by the motor.

  • Working Position


  • Mounting

    Flanged B5

  • Protection

    IP 54

KTY / PTC Motor & Machine Protection

S Series Models Coding