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ST Motors


The range of ST torque motors with high energy iron-neodymium permanent magnets has been designed for the direct drive without gearbox of servo-mechanisms of highly dynamic automated production machines. ST torque motors are characterized by the integration of the active parts of STK kit motors up to a diameter of 300 mm - namely their rotor and stator - in a frame with shields, ball bearings, encoders or resolvers, a hpollow, blind or solid shaft with cable or connector outputs.

ST torque motors therefore have the same advantages as STK motors kits in terms of compactness, torque-to-weight, volume-to-weight, precision and reliability. They offer the machine manufacturer a motor integration when there is no interest in doing it in the machine itself. This is particularly the case for machines in which there is no integration frame. One can in particular  quote  the case of carousels and test benches. Note also the strong interest of ST torque motors in the case of application of cyclic machines with low inertia due to the reduced inertia of the motors despite the high peak torques.


Main characteristics

  • Permanent torque up to 261 Nm and impulse torque up to 1161 Nm

  • Possibility of a through hollow shaft up to 75 mm in diameter

  • Three motor technologies:

HP: high precision with cogging torque < 1% for 145 & 190ST

SP: standard precision with cogging torque = or < 2% for the 145 & 190ST

X: high precision with cogging torque < 2% for 300ST

  • Position sensors:

Resolvers: precision to 1 arcminute or to 10 arcminute.
SinCos encoders: incremental or with commutation tracks
Absolute ENDAT encoders
HIPERFACE encoders

  • IP54 execution

  • Power and low level connections: Class 6 cables, 2 m long

  • Relative humidity: < 85% (non-condensing)


  • High dynamics

  • No gear

  • No mechanical play

  • High precision servo

  • Lowest maintenance

  • Simplification of the servo mechanism

  • Noise reduction

  • Functional optimization and simplification of machines

Données techniques

Characteristics of the range

With respective diameters of 145, 190 and 300 mm, these motors are offered with a wide variety of resolvers and encoders and execution of hollow, blind or solid shafts. Nominal torques vary from 8 to 261 Nm in natural convection for peak torques of 27.5 to 1161 Nm and speeds up to 1500 rpm.

These motors offer exceptional compactness with a permanent mass torque of up to 3.7 Nm/kg and a maximum mass torque of up to 18 Nm/kg. They are also designed to allow a great regularity of rotation at low speed.

Two winding variants are offered as standard: 500 and 1500 rpm for the 145ST, 500 and 1000 rpm for the 190ST and 200 and 800 rpm for the 300ST. However, other versions enabling the rating of the associated drive to be optimized can be easily produced.


145 ST motors 400 Vac / 460 Vac version

  • Permanent torque: from 8 to 47.4 Nm

  • Maximum torque: from 27.5 to 220 Nm

  • Nominal speed: from 500 to 1500 rpm

  • Hollow shaft: diameter 60 mm in standard

190 ST motors 400 Vac / 460 Vac version

  • Permanent torque: from 19 to 111 Nm

  • Maximum torque: from 62 to 496 Nm

  • Nominal speed: from 500 to 1500 rpm

  • Hollow shaft: diameter 75 mm in standard

300 ST motors 400 Vac / 460 Vac version

  • Permanent torque: from 54 to 261 Nm

  • Maximum torque: from 193 to 1161 Nm

  • Nominal speed: from 200 to 800 rpm

  • Hollow shaft: diameter 72 mm as standard

ST Motors Options

Download the Complete Direct Drive Catalog

Wiring of ST motors

Download Torque Motors Application Note

Download of the outline drawings

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