ONOSOKKITachometer FT-2500The FT-2500 advanced tachometer is a device that measures the speed by detecting noise, vibration or changes in magnetic flux generated by motors and various rotating mechanisms. Since its calculation unit uses FFT (fast Fourier transform) technology, the range of sensor selection has been increased. Even complex signal waveforms from microphones, sound level meters or vibration sensors can extract frequency components corresponding to the speed, thereby calculating and displaying the speed. In particular, for some products whose motors are already encapsulated in the components and the shafts are not exposed, it is difficult to measure them using traditional methods. However, using noise or vibration, it is easy to measure the speed of rotation. It is no longer necessary to attach reflective sheets to the measured object or perform special processing on the shaft as in the past. The current FT-2500 is equipped with new calculation processing functions, which makes it have good tracking of the speed. Not only can it accurately measure the steady-state speed of motors or engines, but it can also track the speed changes and measure the dynamic speed with acceleration/deceleration components. The speed test of the thin-axis micro motor that cannot be attached with reflective sheets can easily measure the speed of the rotating shaft of the motor without attaching reflective sheets. For example, it is possible to measure the rotation speed of a fan that cannot directly reflect incident light, or the thin shaft of a micro motor that is difficult to attach a reflective sheet to. In the case of a fan, the fan speed can be simply measured by inputting the number of blades of the fan. Since it is a non-contact measurement, it is very suitable for inspection and testing on the production line. Rotation Direction Determination and Speed Measurement of General-Purpose DC Motors The FT-0501 is used to detect the leakage flux of a general-purpose DC motor and extract a frequency signal that is proportional to the speed. Since there are two coils built in, the two detected signals are phase-shifted, and there is a phase lead and a phase lag. The rotation direction of the motor can be determined based on the principle of phase lead and lag. Therefore, when it is difficult to determine the direction of rotation of the motor visually during quality inspection, it can be used to determine the direction of rotation of a small DC motor, which is a very convenient function. Of course, the leakage flux can also be used to measure the speed of the DC motor. Two-phase output can determine the direction of rotation Equipped with a rotation direction determination output (semiconductor relay), it is convenient to perform CW/CCW judgment detection on the production line. Compressors without rotating shafts are widely used in household refrigerators, commercial vending machines, air conditioners, and car air conditioners. The speed of the compressor can be easily measured by combining an accelerometer with the FT-2500. The accelerometer (NP-3000 series) can be fixed with a magnetic base (NP-0100, 0101), which allows you to place the sensor at any position to obtain the appropriate test results. The two-phase output can determine the direction of rotation. Equipped with a rotation direction discrimination output (semiconductor relay), it is convenient to perform CW/CCW judgment on the production line. Suitable for lock judgment during refrigerator lock test. Using sound pressure to measure the speed of the pump. The speed of the pump can be easily measured using the exhaust noise. The rotating shaft of the pump equipment is usually not exposed to the outside, so it is difficult to measure its speed using ordinary pulse detection methods. This example uses a microphone to measure the rotation speed of the pump by measuring the exhaust sound method. It can be easily done by simply setting the number of blades of the pump fan. The rotating shaft can be measured without exposing it to the surface. Pump speed measurement packaged in household appliances DC motor speed electric toothbrush actually uses a mechanical structure to convert the rotational motion of the DC motor into the linear reciprocating motion of the toothbrush. The motor inside the electric toothbrush cannot be seen rotating after being packaged, but the FT-2500 can measure its speed by detecting the magnetic flux leaking from the rotating motor. Measuring the engine speed using a microphone or vibration sensor The engine speed can be measured by the sound and vibration generated by the movement of the engine piston. This is effective when the engine compartment is covered and the engine speed sensor cannot be installed. The number of pulses is set according to the number of ignitions or combustions per revolution of the engine crankshaft. (Example) The number of pulses for a 4-stroke 4-cylinder engine is set to 2P/R. Measuring the speed using the engine ignition pulse induction coil. Clamp the lead wire of the primary low-voltage coil or secondary high-voltage coil of the gasoline engine with the sensor. If there is a clamp switch, push the clamp switch to measure the engine speed. Just enter the number of ignitions per revolution. Setting the number of pulses means setting the number of ignitions or combustions per revolution. (Example) 4-stroke engine︓ When the sensor is clamped on the primary side, the number of pulses is set to half the number of strokes. When the sensor is clamped on the secondary side, since only one pulse is output for every 2 revolutions, the number of pulses is set to 0.5P/R. Measuring the rotation speed of a small fan using an accelerometer The rotation speed of a rotating body such as a small fan can be measured using a vibration sensor. This is because the vibration of a rotating body depends on the rotational motion, and the vibration frequency of the rotating body is related to the rotation speed. By measuring the vibration frequency, the rotation speed of the rotating body can be measured. Input unit compatible sensors FT-0501/0801, IP-292/296, IP-3000A/3100, VP-202/1220, OM-1200/1500 Constant current drive sensor, various microphones, accelerometers and other test units Measurement mode 1. Steady-state speed measurement mode Frequency range: 500 Hz, 2 kHz, 10 kHz Resolution = frequency range ÷ 12800 × 60 ÷ set number of pulses 2. Speed acceleration/deceleration measurement mode Frequency range: 250 Hz, 500 Hz, 2 kHz Resolution = frequency range ÷ 6400 × 60 ÷ set number of pulses Rotation direction judgment (only measurable when using FT-0501) Measurement accuracy ±2 × rotation speed resolution ±1 digit Count averaging processing Moving average processing, averaging points: OFF, 2, 4, 8, 16 Filter function can be set arbitrarily (upper and lower limits are set one by one) Display unit display refresh time 0.5 ± 0.2 seconds Measurement display range 0 to 999,999 r/min (0 to 10,000 Hz) Output unit analog output voltage range 0 to 10 V/ 0 to FS Speed at 10V output can be set arbitrarily Analog output refresh time Steady speed test mode: < 500 ms Speed acceleration/deceleration test mode: < 250 ms Sensor signal monitoring output For monitoring sensor signals (used alternately with analog output) Comparison output upper and lower limit judgment, Rotation direction judgment, OK/NG judgment Output method: semiconductor relay (3 sets of circuits built-in) Pulse output Output displayed speed × set P/R equivalent frequency (Hi: > 4.5 V; Lo: < 1 V) External interface RS-232C, also the input end of external commands Storage unit ※ Status memory can store 3 setting conditions