【 Rotation Sensor 】 Electromagnetic Pickup

Convert rotational speed to frequency


■ A power-generating rotation pickup sensor made up from a magnet and a coil.
■ The sensor is mounted close to the detection gear (a rotating body), and an electrical signal can be obtained with a frequency proportional to the rotational speed.


This sensor is a power-generating rotational pickup sensor comprised of a magnet and a coil.
By mounting the sensor close to the magnetic detection gear, which is mainly installed on the rotation axis (of the rotating body), an electrical signal can be obtained which has a frequency proportional to the rotational speed.
When the signal white line is taken as 0V, a plus voltage is generated and output when the magnetic body comes close to the tip of the sensor, but a minus voltage when moving away from it.


Model GM12
Name Rotation pickup sensor
DC resistance Approx. 2.2kΩ
Detection gear (rotating body)

Module 1 to 3 (module = pitch circular diameter / number of gears)
Material   Magnet material (e.g. S45C, SS400)
Width of gear teeth   3mm or more

  Output voltage

f=1kHz  For the module = 1 condition (GAP = space between the tip of the sensor and the rotating body)
2.0Vp-p (GAP=0.5mm Load resistance=10kΩ) (TYP)
0.5Vp-p (GAP=1.0mm Load resistance=10kΩ) (TYP)
2.4Vp-p (GAP=0.5mm Load resistance=∞Ω) (TYP)
0.6Vp-p (GAP=1.0mm Load resistance=∞Ω) (TYP)

  Signal cable

Sheath PVC   Approx. φ5 Balanced shield cable 2m
Red (+), White (-)

  Magnet polarity   Tip N pole
 Polarity of output power generated  When the magnetic body approaches the tip, the (+) signal line is a + polarity
 Operating temperature range  -10 to +100ºC
 External dimensions  M12(P=1) L:46
 Weight  Approx. 95g (including the cable)
 Accessories   2 nuts (M12 B17 H3 P1 double-chamfered), 1 toothed washer

External dimensions diagram