Can LM encoder systems be used in linear motors?
Yes, LM series magnetic encoders are perfectly suitable to be used with linear motors. However, to achieve optimum performance of your encoder the influence of linear motor magnetic flux on magnetic encoder accuracy error needs to be taken into account.
Linear motors are electric motors that produce linear motion. In a traditional electric motor, the rotating part (rotor) spins inside the static part (stator), whereas in a linear motor, the stator is laid out flat and the ‘rotor’ is a slider that moves in a straight line above the stator.
In below example, the stator in linear motors consists of permanent magnets and the slider contains the coils/windings. The magnets used in linear motors are usually very strong and therefore have a very high magnetic flux which can affect the accuracy of a magnetic encoder. However, the strength of a magnet decreases with distance as well as with addition of an external shield.
The graphs and table below show the influence of linear motor magnets on LM encoder accuracy depending on the distance (A) of the encoder from the linear motor magnets.
| Distance of encoder from linear motor magnets (A) | Accuracy (µmpp) | Accuracy plot |
| 0 | 14 |  |
| 5 | 9 |  |
| 10 | 6 |  |
| 15 | 5 |  |
| >15 | 4 |  |
