Qingdao CSK Motion Technology Co., Ltd.
Qingdao CSK Motion Technology Co., Ltd.

Linear motor technical terms to answer

Backdynamic constant

Is the ratio of the back emf voltage (Rm s) to speed [r p m] or speed [m/s]. The back EMF is the voltage that occurs when a coil moves on a permanent magnet, as in a servomotor.

To speed up the degree of

Change in velocity per unit time, that is, acceleration = velocity/time or a= V /t

To speed up the time

The time required to accelerate to maximum speed from rest.

Flatness (or straightness)

Straight-line motion characteristics when moving in the X direction, when this standard is bad when moving in the X direction, errors in the Z direction will occur.


For the force that makes the object rotate, M=rxF1 is generally expressed as the vector calculated by the formula of the cross product below, and its physical unit is Nm = kgm2/s2


Do not mix with absolute precision, a linear positioning axis will generally have poor absolute accuracy, and good reproducibility. Performed at more than a certain interval

The measured result of moving from the same direction to the target is called unidirectional reproducibility. In this case, the influence of backgap, for example, is absent. If the measurement approaches to the target in different directions, the results obtained are two-way reproducibility, and the results including backgap will be measured

Motor constant Km

[See 1.3km)

Is the ratio of thrust to power consumption, and represents the power of the motor.


Is the ability of the organization (including parts or components) to resist deformation, which is generally divided into static rigidity and dynamic rigidity.

True straightness (or horizontal straightness)

The horizontal and linear motion characteristics when moving in the X direction. when this standard is bad, when moving in the X direction, an error in the Y direction will occur.


Refers to the torque motor in the rotation of the rotation center offset, mainly by the assembly of the center and bearing tolerance.

Thrust, torque.

The thrust of linear motion and the torque of rotational motion have different definitions according to different circumstances. General: room temperature 20°C coil temperature 80°C100% duty cycle of continuous thrust, continuous torque, or instant thrust, instant torque, etc.

Thrust constant Kf

[See 1.3kf]

Is one of the characteristics of the motor coil, defined as the thrust per unit current, the thrust can be obtained by multiplying this parameter by the current: F= L ×Kf

Continuous thrust, continuous torque

(see 1.3 Fc]

The amount of thrust or torque that a motor can produce when a connection current of duty cyclel is applied to the motor coil.

After the current

(see 1.31 c)

This current is the current that can be continuously supplied to the motor coil. In general, when this current flows through the coil, the maximum temperature will not exceed 80°C.


The minimum interval between the energy measured by the azimuth feedback system itself is not to be confused with the motion resolution, which is usually greater than the resolution.

The deflection

A visual error in the rolling plane for the rotation motor. As it rotates, the upper plane of the motor will tilt to and fro, resulting in a viewpoint. The main reason is caused by bearing tolerance. .

Motion resolution

Factors affecting the minimum interval at which the positioning system can repeat motion include the resolution of the azimuth feedback system, the resolution of the controller driver plus the tissue backlash, etc.


Defined as the error between the target bearing and the actual bearing. Such systematic or linear errors may come from cosine errors, viewpoint errors, screw errors, thermal expansion and other elements. Accuracy should not be mixed with reproducibility accuracy.

Magnetic attraction Fa

The force between the actuator and the stator of a core motor, which forms a preload on the slider and is received by the slider.

Coil resistance R25

Is the characteristic of the motor coil, resistance at 25C; If at 80°C the resistance becomes about 1.2 times

Coil temperature Tmax

[See 1.3t]

The maximum temperature allowed for the coil, the actual temperature of the motor depends on the organization, cooling means and motion planning and so on elements, theoretical calculation may have errors, generally based on the actual test.

Guide rail error.

The linear error of the slide is dependent on true straightness and flatness.

Instantaneous current LP

(see 1.31 p]

It is mainly used to supply the current with large thrust in a short time. The basic principle of HIWIN motor definition is: LP of LMS series is twice the continuous current; LMC

Series Ip is three times the continuous current. The moment of instantaneous current supply is one second, and then the full heat dissipation period of time to return to the normal working temperature of the coil below, to be able to supply the instantaneous current.

Instant torque, instant thrust Fp

Instantaneous torque [rotation motion], instantaneous thrust (linear motion) is the maximum thrust that the motor can produce at the moment of not more than one second, generally such thrust is now close to the full nonlinear operating region of the motor, generally used for the purpose of speeding up or slowing down.

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