Magneto-electric rotation detector
AP-981
Acid-proof, water-proof Non-contact gear detection type
The AP-981 is protected against nitric acid fume concentrations up to 10% and is of immersion-proof construction. Although it is not exclusively for underwater use, it complies with protection level 7 (IP X7), so it can be used even in environments where it may occasionally be submerged.
It is a magneto-type detector using an internal magneto resistive element,
a permanent magnet, DC amplifier, and voltage regulator and responding to flux (i.e., the resistance value changes in response to flux changes),
so that a rectangle waveform is output from ultra low speed to high speed (1 to 20,000 r/min (60 P/R)).
AP-981: the signal cable is directly output cable of 1.9 m length.
There are 2 types of othere detectors:
Features
- Detectable from ultra low speed (almost 0 r/min)
- Safe detection as non-contact detection
- Compact, lightweight and easy to install
- Installation at any position where a gear can be mounted on the measurement target.
- Measurement capability in environments subject to submersion and in nitric acid mist atmospheres.
Detection gears
Specification of gears
| Shape of gear | Involute gear or equivalent |
|---|---|
| Module | 1 to 3 |
| Tooth width | 3 mm or more |
| Material | Strong magnetic properties (e.g., S45C, SS400 etc.) |
Relationship between detection distance and gear modules
The detection distance depends on the modules of detective gear, with longer distances being possible with larger modules. Also detection distance depends on temperature. In cases where the ambient temperature varies greatly, it should be mounted with minimum of detection distance. The detectable range shown in the right figure assumes an output waveform duty cycle of 50 % ±20 %.
Precautions of installation
The detectors (MP-9800 series/AP-981) shall be positioned properly
by aligning the center of the gear teeth with the positioning mark on the detector.
Rotation Detectors Classification table
MP series Rotation Detector Classification table
（PDF 2.3 MB）
Specifications
| AP-981 | |
|---|---|
| Detection method | Magneto resistive element and electromagnetic property gear |
| Detective gear | Strong magnetic properties (e.g., S45C, SS400 etc.), |
| Module 1 to 3, teeth width 3 mm or more | |
| Detection distance | Depends on gear module |
| Measurement range | 1 Hz to 20 kHz (using a 60 P/R of detection gear) |
| Output waveform | Rectangular waveform Hi level:+5 ± 0.5 V or less, Lo level:+ 0.5 V or less |
| Output impedance | Approx. 330 Ω |
| Applicable tachometers | TM-4000 series |
| Power requirement | VDC 12±2, approx. 40 mA |
| Protection circuit | Power supply polarity protection |
| Operating temperature range | −10 ℃ to ＋70 ℃ |
| −10 ℃ to ＋50 ℃ （with a nitric acid mist concentration of 10%） |
|
| Withstand voltage | |
| Maximum vibration (powered on) |
1.2 mm double-sided amplitude at 30 Hzin X, Y and Z directions for one hour each |
| Maximum shock (unpowered) |
490 m/s2 in X,Y and Z directions three times each |
| Outline dimension |  |
| Weight | Approx. 130 g （including signal cable） |
| Signal cable | Nitric acid resistant cable 1.9 m, direct output |
| Remarks | Outer surface material : PolycarbonateWaterproof type, conforming to protection class IPX7 according to JIS C0920Acid-resistant type, can be used in nitric acid mist atmosphere |
Related information
Last update : 2026/1/16