To ensure that it is clear what we are talking about, below you will find definitions of all of our technical parameters, details from the product data sheets and all characteristic values of our products.

## Glossary

### A

Describes the amplitude of the bemf.

The angular accuracy of step describes the deviation of the current rotor position from the ideal target rotor position, whereby no external load is applied.

Specifies the maximum angle of the output shaft of the eccentric that may be set while in operation.

Specifies the minimum angle of the output shaft of the eccentric that may be set while in operation.

Stiffness of the bearing in the axial direction, i.e., elastic deflection of the mounted shaft in the axial direction as a function of the applied force.

### B

The bidirectional repeatability describes the positional uncertainty that arises when repeatedly approaching a setpoint from the opposite direction with no load.

The repeatability is defined as half of the maximum difference together with a +/- sign.

The backlash can be ascertained from the characteristic of the hysteresis curve of a gear or linear actuator.

Backlash is defined as the range in which the characteristic of the hysteresis curve is vertical, i.e., an angular change or a positional change occurs without changing the torque or the force.

The hysteresis curve is determined by subjecting the output to load while the input is blocked with a clockwise and an anticlockwise torque or a forward-acting and a backward-acting force and the corresponding angular displacement or positional change measured.

### E

The eccentricity is the distance of the rotary axis of the input shaft to the axis of the eccentric.

The electrical time constant describes the time required to achieve 67% of the possible phase current of a specified operating point.

### F

The full step angle of the motor describes the angle at which the rotor turns if a phase is advanced.

### G

Possible deflection or position change of the mounted body in the y-direction without applied force.

Possible deflection or position change of the mounted body in the z-direction without applied force.

### H

Describes the torque developed by the motor while at a standstill.

Refers to the smallest diameter that is available to the application on the central rotary axis of the entire drive train.

### I

Describes the inductance of the coil of a phase at an ambient temperature measured at 1 kHz.

Describes the insulation voltage of the motor.

### L

The value for the lost motion can be ascertained from the characteristic of the hysteresis curve of a gear or linear actuator.

Lost motion is defined as the angular difference or position difference at which the two branches of the hysteresis curve cross the torque or force zero point, i.e., no load is applied.

The hysteresis curve is determined by subjecting the output to load while the input is blocked with a clockwise and an anticlockwise torque or a forward-acting and a backward-acting force and the corresponding angular displacement or positional change measured.

### M

The magnetic flux density describes the magnetic field that still exists outside of the motor. Fundamentally, the magnetic flux density defines the force on a current-carrying conductor in a magnetic field.

The magnetic flux density describes the magnetic field that still exists outside of the motor. Fundamentally, the magnetic flux density defines the force on a current-carrying conductor in a magnetic field.

The (mass) moment of inertia specifies a body’s resistance to change its rotational movement.

The maximum temperature that may occur in the coil without destroying the magnets or the coil.

The coil temperature can be calculated by measuring the change in resistance and the temperature coefficient alpha, which is dependent on the coil wire material. T1 = 1/alpha * (R1/R0 + alpha*T0 – 1)

Maximum permissible current at which continuous operation of the drive is possible without the motor overheating while at an ambient temperature of 20°C.

The maximum input speed refers to the speed before which mechanical damages occur to components in the drive train, e.g., scoring of the teeth or damage to the ball bearings.

With drive systems, the motor torque may, in some cases, not be adequate for overcoming the running torque of the complete system at maximum speed.

Specifies the maximum force that may act on the flexure hinge without the exceeding the continuous fatigue strength limit value.

The maximum output speed or maximum speed refers to the speed before which mechanical damages occur to components in the drive train, e.g., scoring of the teeth.

With drive systems, the motor torque may, in some cases, not be adequate for overcoming the running torque of the complete system at maximum speed.

Maximum permissible temperature at which the drive can still be operated.

Maximum permissible temperature at which the drive may be stored or decommissioned without being impaired or destroyed as a result.

Describes the maximum permissible axial load on the input shaft, whereby the drive is in operation, i.e., is turning, and the force is applied impulsively. Decisive for the determination is the dynamic load bearing capacity of the ball bearings, which, in the impulsive case, corresponds to just one third of Cr.

Describes the maximum permissible axial load on the input shaft, whereby the drive is in operation, i.e., is turning, and the force is applied statically. The dynamic load-bearing capacity of the ball bearings is decisive for the determination.

Describes the maximum permissible axial load on the input shaft, whereby the drive is not in operation, i.e., is at a standstill and the force is applied impulsively. Decisive for the determination is the static load bearing capacity of the ball bearings, which, in the impulsive case, corresponds to just one third of Co.

Describes the maximum permissible axial load on the input shaft, whereby the drive is not in operation, i.e., is at a standstill and the force is applied statically. The static load-bearing capacity of the ball bearings is decisive for the determination.

Describes the maximum permissible axial load on the output shaft, whereby the drive is in operation, i.e., is turning, and the force is applied impulsively. Decisive for the determination is the dynamic load bearing capacity of the ball bearings, which, in the impulsive case, corresponds to just one third of Cr, as well as the elastic deformation of the output shaft due to the stiffness of the output bearing and the associated change in position of the dynamic spline.

Describes the maximum permissible axial load on the output shaft, whereby the drive is in operation, i.e., is turning, and the force is applied statically. Decisive for the determination is the dynamic load bearing capacity of the ball bearings as well as the elastic deformation of the output shaft due to the stiffness of the output bearing and the associated position of the dynamic spline.

Describes the maximum permissible axial load on the output shaft, whereby the drive is not in operation, i.e., is at a standstill and the force is applied impulsively. Decisive for the determination is the static load bearing capacity of the ball bearings, which, in the impulsive case, corresponds to just one third of Co, as well as the elastic deformation of the output shaft due to the stiffness of the output bearing and the associated position of the dynamic spline.

Describes the maximum permissible axial load on the output shaft, whereby the drive is not in operation, i.e., is at a standstill and the force is applied statically. Decisive for the determination is the static load bearing capacity of the ball bearings as well as the elastic deformation of the output shaft due to the stiffness of the output bearing and the associated position of the dynamic spline.

Describes the maximum permissible radial load on the input shaft, whereby the drive is in operation, i.e., is turning, and the force is applied impulsively. With impulsive loading, the permissible dynamic load-bearing capacity of the ball bearings is reduced to one third of Cr. Likewise decisive for the determination are, in addition to the load-bearing capacity of the ball bearings, the elastic deformation of the input shaft near the sun gear wheel and the associated run-out error due to the stiffness of the bearing.

Describes the maximum permissible radial load on the input shaft, whereby the drive is in operation and the force is applied statically. Particularly important for the determination of the permissible force in the dynamic case are, in addition to the load-bearing capacity of the ball bearings, the stiffness of the bearing and the run-out error on the sun gear wheel caused by elastic deformation. For the permissible force, the worst case is assumed as the point of force application, i.e., the maximum distance between ball bearings and the end of the input shaft.

Describes the maximum permissible radial load on the input shaft, whereby the drive is not in operation, i.e., is at a standstill and the force is applied impulsively. The load-bearing capacity of the ball bearings is decisive for the determination. With impulsive loading, the permissible load-bearing capacity of the bearings is reduced to one third of Co.

Describes the maximum permissible radial load on the input shaft, whereby the drive is not in operation, i.e., is at a standstill and the force is applied statically. The static load-bearing capacity of the ball bearings Co and the geometric relationships from the point of force application and the bearing distance are decisive for the determination. For the permissible force, the worst case is assumed as the point of force application, i.e., the maximum distance between ball bearings and the end of the input shaft.

Describes the maximum permissible radial load on the output shaft, whereby the drive is in operation, i.e., is turning, and the force is applied impulsively. With impulsive loading, the permissible dynamic load-bearing capacity of the ball bearings is reduced to one third of Cr. Likewise decisive for the determination are, in addition to the load-bearing capacity of the ball bearings, the elastic deformation of the output shaft near the dynamic spline and the associated run-out error due to the stiffness of the bearing.

Describes the maximum permissible radial load on the output shaft, whereby the drive is in operation and the force is applied statically. Particularly important for the determination of the permissible force in the dynamic case are, in addition to the load-bearing capacity of the ball bearings, the stiffness of the bearing and the run-out error on the dynamic spline caused by elastic deformation. For the permissible force, the worst case is assumed as the point of force application, i.e., the maximum distance between the ball bearings and the end of the output shaft.

Describes the maximum permissible radial load on the output shaft, whereby the drive is not in operation, i.e., is at a standstill and the force is applied impulsively. The load-bearing capacity of the ball bearings is decisive for the determination. With impulsive loading, the permissible load-bearing capacity of the bearings is reduced to one third of Co.

Describes the maximum permissible radial load on the output shaft, whereby the drive is not in operation, i.e., is at a standstill and the force is applied statically. The static load-bearing capacity of the ball bearings Co and the geometric relationships from the point of force application and the bearing distance are decisive for the determination. For the permissible force, the worst case is assumed as the point of force application, i.e., the maximum distance between the ball bearings and the end of the output shaft.

The maximum speed of the motor describes the speed before mechanical damages occur to the commutator, the rotor or the bearing.

Specifies the maximum available travel range of an eccentric kinematics.

Minimum permissible temperature at which the drive can be operated.

Minimum permissible temperature at which the drive may be stored or decommissioned without being impaired or destroyed as a result.

With momentary peak torque or momentary peak force, the elastic deformations of the teeth are still small enough that no tooth meshing problems occur and proper function is ensured.

The loads do, however, exceed the limit of the fatigue strength. Thus, the number of loads should be minimised.

Should it occur once, breakage or failure will not result.

With drive systems, the motor torque may, in some cases, not be adequate for overcoming the running torque of the complete system at momentary peak torque or momentary peak force.

### N

Describes the current consumption of the unloaded motor in the steady state, i.e., constant speed, at an ambient temperature of 20°C.

The running torque describes the torque necessary for driving the gear without additional output-side load at 20°C and standard lubricant at constant speed.

The no-load starting torque describes the torque necessary for putting the gear into rotary motion without additional output-side load at 20°C and standard lubricant.

### O

Describes the characteristic of the linear resulting operating force that can be applied by the positioning system as a function of the angular position of the eccentric.

It is defined such that at an angular position of 0 degrees, the eccentric is perpendicular to the resulting movement direction.

Possible deflection of the mounted shaft in the axial direction without applied force.

Possible deflection of the mounted shaft in the radial direction without applied force.

### P

The peak torque or peak force is the loading of the components in the drive train, e.g., the teeth of the gears, still below the fatigue strength.

This does, however, result in increased tooth wear, which leads to a reduction in the service life.

With drive systems, the motor torque may, in some cases, not be adequate for overcoming the running torque of the complete system at peak torque or peak force.

The phase resistance describes the ohmic resistance of the coil of a phase at an ambient temperature of 20°C in the steady state.

The positioning accuracy of a gear describes the maximum deviation of the output angle relative to the setpoint or, with a linear actuator, the maximum deviation of the output position relative to the setpoint.

The measurement is performed during a complete rotation of the output element or a complete traverse of the travel range path with the aid of a high-resolution measurement system.

There is no change in the direction of rotation or direction reversal.

The positioning accuracy is defined as the absolute value of the maximum difference between the theoretical setpoint position and the measured actual position of the output element.

The positioning resolution refers to the smallest angular change or positional change that can be distinguished by the positioning system.

With eccentric systems, the characteristic of the linearly resulting positioning resolution is described as a function of the angular position and thereby indicates the smallest positional change as a function of the angular position that can be distinguished by the positioning system.

With eccentric systems, it is defined such that at an angular position of 0 degrees, the eccentric is perpendicular to the resulting movement direction.

### R

Stiffness of the bearing in the radial direction, i.e., elastic deflection of the mounted shaft in the radial direction as a function of the applied force.

The phase current that may flow through both phase coils without the motor overheating while at an ambient temperature of 20°C and constant operation.

Rated input speed is defined as the speed at which the service life is achieved under rated conditions, i.e., rated torque.

With drive systems, the motor torque may, in some cases, not be adequate for overcoming the running torque of the complete system at rated speed.

Rated output speed or rated speed is defined as the speed at which the service life is achieved under rated conditions, i.e., rated torque or rated force.

With drive systems, the motor torque may, in some cases, not be adequate for overcoming the running torque of the complete system at rated speed.

The rated running torque describes the input-side torque that is required to operate the gear in rated operation, i.e., at rated torque and rated speed.

The rated speed of the motor describes the speed at which the steady state is reached at rated conditions, i.e., rated torque and rated current.

Rated torque or rated force is defined as the torque or force at which the service life is achieved under rated conditions, i.e., rated speed.

With drive systems, the motor torque may, in some cases, not be adequate for overcoming the running torque of the complete system under rated conditions.

The rated voltage corresponds to the voltage at which all other rated characteristic values of the motor, particularly the rated current at 20°C, are set, measured and classified.

The reduction ratio describes the relationship between the input movement and the output movement. With a reduction ratio, the output movement is smaller than the input movement.

Describes the ratio of an input-side movement to the output-side movement quantity that results from the lever kinematics of a flexure hinge.

Describes the step frequency at which the rotor can experience resonance vibrations while the motor is operated under no load. It is recommended that this frequency be avoided in normal operation and that the motor be started at a higher frequency or that half- or micro-steps be used. Additional inertial masses, e.g., through a gear, reduce the resonance frequency.

At Micromotion GmbH, hazardous materials, which are referred to in EU directive 2011/65/EU, are purchased/used only in compliance with this directive.

The running torque characteristic describes the input-side torque that is required to operate the gear as a function of torque and speed.

### S

With self-locking, the forces caused by friction are always greater than the applied adjustment forces due to the geometric relationships of the sliding partners. Due to the geometric conditions, the sliding partner in which the force is initiated cannot be moved relative to the sliding parter on which the adjustment force is applied.

The service life is defined by means of the rated operating point, i.e., rated speed and rated torque, as well as a change of the accuracy characteristics, i.e., unidirectional repeatability, transmission accuracy, lost motion, of less than 10% of the respective catalogue value.

Describes the characteristic of the resulting speed as a function of the angular position of the eccentric at constant output speed.

It is defined such that at an angular position of 0 degrees, the eccentric is perpendicular to the resulting movement direction.

Describes the dependence between speed and applied voltage of the unloaded motor in the steady state, i.e., constant speed, at an ambient temperature of 20°C.

Describes the torque developed by the motor while at a standstill.

The drive can be sterilised especially for medical applications in an autoclave.

Stiffness of the bearing in the x-direction, i.e., elastic deflection of the mounted body in the x-direction as a function of the applied force.

Stiffness of the bearing in the y-direction, i.e., elastic deflection of the mounted body in the y-direction as a function of the applied force.

Stiffness of the bearing in the z-direction, i.e., elastic deflection of the mounted body in the z-direction as a function of the applied force.

### T

Describes the thermal resistance of the motor between coil and housing.

Describes the thermal resistance of the motor between housing and ambient air.

Describes the thermal time constant of the motor coil.

Describes the thermal time constant of the motor housing.

The torque characteristic or operating force characteristic describes the possible output torque or possible output force as a function of the output speed.

Describes the dependence between torque and current of the motor at an ambient temperature of 20°C.

The torsional stiffness can be ascertained from the characteristic of the hysteresis curve of a gear.

The torsional stiffness is defined as the slope of the hysteresis line and describes the elastic torsional angle of the output shaft as a function of a torque.

The hysteresis curve is determined by subjecting the output to load while the input is blocked with a clockwise and an anticlockwise torque and the corresponding angular displacement measured.

Describes the travel range available for the application.

Describes the characteristic of the travel range as a function of the angular position of the eccentric. It is defined such that at an angular position of 0 degrees, the eccentric is perpendicular to the resulting movement direction and has no deflection in the adjustment direction.

The transmission accuracy of a gear describes the linearity error between input and output angle.

The measurement is performed during a complete rotation of the output element with the aid of a high-resolution measurement system.

There is no change in the direction of rotation.

The transmission accuracy is defined as the sum of the absolute values of the maximum positive and negative deviation between the theoretical and the measured angular position of the output shaft.

### U

The unidirectional repeatability describes the positional uncertainty that arises when repeatedly approaching a setpoint from the same direction with no load.

The repeatability is defined as half of the maximum difference together with a +/- sign.

### V

HV (high vacuum) corresponds to a pressure range from 10E-3 to 10E-7mbar. UHV (ultra-high vacuum) corresponds to a pressure range from 10E-7 to 10E-12mbar. The vacuum-compatibility is influenced by the used materials as well as the lubricant. In addition, the design must not have any cavities or inclusions. The achievable vacuum quality is likewise dependent on the design of the used motor.

### W

The weight of the drive without cables and plugs.