Measure the motor and load speed, and how to measure the torque of the motor

Under normal circumstances, the motor vibration value needs to be within a certain range. This range can vary depending on factors such as the type of motor, working condition, and environmental conditions. Typically, motor vibration values are measured and measured by vibration sensors.

For different types and models of motors, the range of normal vibration values is also different. For example, for some high-speed motors, the vibration value may be relatively small, generally between mm s; However, the vibration value of some low-speed and high-power motors may be relatively large, generally between mm s. For some special motors, such as wind turbines, the vibration value may be even greater, generally reaching tens or even hundreds of mm s.

This requires a speed sensor, which is a lot of non-contact, usually requires the addition of a gear to the measured shaft, the sensor detects the rotation of the gear, and each tooth will produce a pulse signal. The rotational speed is obtained by calculating the number and time of the mobile phone pulses. The general principle is to use the Hall effect.

To measure the torque of a motor, a torthrometer is required. The tachometer will receive a digital pulse signal (sent by the sensor), process it, and read it directly into the counting port of the CPU.

The software calculates the speed and the corresponding position of the pointer, and then through the control port of the CPU, the stepper motor is driven to rotate in the positive and negative directions after amplification, indicating the corresponding speed value (the pointer is directly installed on the rotation axis of the stepper motor), and the stepper motor takes only 1 3 degrees.

Torque (also known as torque) is a special moment in physics, which is equal to the product of force and force arm, and the SI unit is Nm n·m, and you can also see units of torque such as kg·m and lb-ft.

The relationship between motor frequency and rotational speed can be expressed by the formula n = 60 f p.

n—motor speed** minutes).

60—per minute (seconds).

f—Power supply frequency (Hz).

p—the number of pole pairs of the rotating magnetic field of the motor.

Determinants of motor speed:

For synchronous motors or asynchronous motors, the speed of the motor is related to the frequency of the power supply, the number of pole pairs of the motor inspection bureau, the higher the power supply frequency, the fewer the number of pole pairs, the higher the speed; In the case of asynchronous motors, it is also related to the current through the electric coil, the higher the current, the closer its rotational speed is to the synchronous speed. There is also a type of guessing motor (usually AC and DC electric lozenge machine), the speed of which has nothing to do with the frequency of the power supply. It is only related to the magnitude of the current passing through the coil.

General motor speed:

Class 2 motor 3000 rpm.

4-stage motor 1500 rpm.

Class 6 motor 1000 rpm.

Class 8 motor 750 rpm.

Class 10 motor 600 rpm.

16-stage motor 500 rpm.

There are several ways to measure motor speed, and here are a few commonly used methods:

1.Rely on a speed sensor: Motors are usually equipped with a speed sensor that allows them to read their speed directly. In general, the accuracy and reliability of this method are high.

2.Use speed measuring instruments: Use professional speed measuring instruments, such as speedometers, tachometers, etc., to measure the speed of the motor. This method is generally more accurate, but requires specific equipment.

3.Using Hall sensors or limb devices: Hall sensors detect the magnetic poles on the motor's rotor to measure rotational speed. This method is relatively simple and easy, but it may not be as accurate as other methods.

4.Utilizing a photoelectric sensor: A photoelectric sensor is installed on the motor to calculate the rotational speed by detecting reflective fringes on the rotor. This method can measure the rotational speed relatively accurately, but requires high installation accuracy and equipment cost.

It should be noted that the measurement of the motor speed should be carried out when the motor is running normally, and the appropriate measurement method and equipment should be selected according to the actual needs.

with a rotational speed sensor.

1. The speed sensor is a sensor that converts the speed of a rotating object into power output. Rotational speed sensors are indirect measuring devices that can be manufactured using mechanical, electrical, magnetic, optical, and hybrid methods. According to the different signal forms, the speed sensor can be divided into two types: analog and digital.

2. The speed sensor is a new type of speed sensor with a magnetoresistor as the sensing element. The core component is a magnetistor as the detection element, and then through a new signal processing circuit to reduce noise and improve the function. By comparing the output waveform with other types of tooth speed sensors, the error of the measured speed is very small and the linearity is very consistent.

The sensing object is a magnetic material or a magnetically permeable material, such as magnet steel, iron mass or electrical steel.

The calculation formula is speed n = 60f p, n is the speed, f is the frequency, and p is the number of pole pairs of the motor.

The generator speed is the maximum number of revolutions that can be completed in one minute at the rotational speed of the generator spindle. The speed of the reed branch is one of the important parameters to mark the engine grade, and it is one of the key factors that determine the internal transmission rate of the engine. The rotational speed of the generator is usually expressed in revolutions, and the notation is r min.

Linear speed and rotational speed

Linear velocity is also divided into mean and instantaneous values. If the time interval is very small, the result is the instantaneous linear velocity.

Note that when t is small enough, the arc ab becomes almost a straight line, and the length of the ab arc is almost indistinguishable from the length of the ab line segment, at this time, l is the displacement of the object from a to b. Thus, v here is actually the instantaneous velocity in a straight motion, but it is now used to describe circular motion.

Linear velocity is a vector, with magnitude and direction, and the line of an object moving in a circular motion changes the direction of velocity from time to time, and always points to the tangent direction of the point.

Summary. Light reflectometry. That is, draw a white line in the rotating part of the motor, irradiate it with a strong beam of light, use the optoelectronic element to detect the reflection, form a pulse signal, and count the pulse within a certain period of time, and the motor speed can be converted.

2. Magnetoelectric method. That is, a magnet is fixed in the rotating part of the motor, and a coil is set at the outer edge of the circumference of the magnet's motion trajectory, and the coil will produce an induced pulse voltage when the motor rotates, and the pulse is counted within a certain period of time, and the motor speed can be converted.

3. Grating method. That is, a disc is fixed on the motor rotation shaft, the disc can have a light groove, a light-emitting element and a light-receiving element are arranged on both sides of the disc, when the motor rotates, the light-receiving element is periodically illuminated, an electric pulse is generated, and the pulse is counted within a certain period of time, and the motor speed can be converted.

4. Hall switch detection method. That is, a magnet is fixed in the rotating part of the motor, and a Hall switch is set at the circumferential outer edge of the magnet movement trajectory, and when the motor rotates, the Hall switch cycle should be magnetic field lines to generate pulse voltage, and the pulse is counted within a certain period of time, and the motor speed can be converted.

No, no. Light reflectometry. That is, draw a white line in the rotating part of the motor, irradiate it with a strong beam of light, use photoelectric components to detect the reflective plexus, form a pulse signal, and count the pulses in a certain time plexus, and the motor speed can be converted.

2. Magnetoelectric method. That is, a magnet is fixed in the rotating part of the motor, and a coil is set at the outer edge of the circumference of the magnet's motion trajectory, and the coil will produce an induced pulse voltage when the motor rotates, and the pulse is counted within a certain period of time, and the motor speed can be converted. 3. Grating method.

That is, a disc is fixed on the motor rotation shaft, the disc can have a light groove, a light-emitting element and a light-receiving element are arranged on both sides of the disc, when the motor rotates, the light-receiving element is periodically illuminated, an electric pulse is generated, and the pulse is counted within a certain period of time, and the motor speed can be converted. 4. Hall Kai infiltration Zheng Yuguan detection method. That is, a magnet is fixed in the rotating part of the motor, and a Hall switch is set at the circumferential outer edge of the magnet movement trajectory, and when the motor rotates, the Hall switch cycle should be magnetic field lines to generate pulse voltage, and the pulse is counted within a certain period of time, and the motor speed can be converted.

Now the best thing to use is the digital speed measuring instrument, there are many manufacturers, you can search on the Internet, you can even buy the sensor to measure. In the past, there was a hand-held mechanical revolution meter that could measure the number of revolutions when touched to the shaft. Now there are photoelectric reflection measurement of the number of revolutions, pasting a reflective self-adhesive at the measurement point, measuring the reflected light pulse when turning, and stopping more.

In terms of measurement principle, there are: centrifugal force detection method, photoelectric code disc speed measurement method, and space filter detection method.

The use of photoelectric digital tachometer can obtain high-precision measurement values, especially when measuring high-speed motors.

Measurement method: paste the reflective mark on the rotating shaft of the motor, press the switch of the TKH609 digital tachometer, align the visible light of the tachometer with the reflective mark, and obtain a high-precision motor speed value after the measured value is stable.

Measurement of the characteristic speed of the asynchronous motor of the inverter:

The measurement of the speed of asynchronous motor mainly includes tachogenerator and photoelectric digital speed measurement.

1) Tachogenerator.

Tachogenerator measurement of motor speed is an early application of speed measurement method. It is the principle that the output voltage of the DC generator is proportional to the speed, and a small DC generator is installed on the shaft of the motor under test, that is, the tachogenerator, and the steady-state speed and speed change law of the motor under test are indirectly obtained according to the output voltage of the tachogenerator. Due to its slow dynamic response, this method can only be used for steady-state measurements or slow-change process measurements.

However, when the rotational speed is low, the tachogenerator will enter the nonlinear region and produce a large error.

2) Photoelectric digital speed measurement.

Photoelectric digital speed measurement is a method of measuring the speed of a motor by changing the optical signal into an electrical signal related to the speed through a speed sensor. The rotational speed sensor mainly has a photoelectric code disc or a grating, which can generate a velocity-related pulsed electrical signal, and can achieve high measurement accuracy due to the high resolution of the grating.

There are two methods for speed measurement using the signal generated by the speed sensor: frequency measurement method and cycle measurement method. The so-called frequency measurement method is to measure the rotational speed by measuring the number of pulses proportional to the rotational speed in the standard unit time, and the velocity measurement waveform is shown in Figure 2-17, which is suitable for the measurement of rotational speed when the rotational speed is relatively high. The circumferometry method, on the other hand, is the opposite of the frequency measurement method, which measures the time it takes to generate an electrical impulse signal (i.e., the fixed angular displacement of the motor to turn around), which is suitable for low speed measurements.

Tachogenerator: The motor rotates to drive the tachogenerator to rotate, and the rotor of the tachogenerator cuts the magnetic field lines to generate induced electromotive force, the higher the speed, the greater the induced electromotive force.

Optical encoder: the grating principle. The motor drives the encoder to rotate and emit high-speed pulses, the higher the speed, the faster the pulse frequency.

Tachogenerator method, tachometer method, light strobe method, counter method.

Tachogenerators can be used.

Encoders can be used.

The tachometer is divided into contact and non-contact.

Contact type means that the measuring head of the tachometer is in contact with the shaft of the motor. It is usually placed in the center hole of the motor shaft, but sometimes it is not possible to do so (e.g., connecting with the backrest wheel of the mechanical part).

Generally, it is safer to use non-contact type. The non-contact type has a photoelectric type, as long as a reflective strip is pasted on the shaft, the tachometer can be measured. No wiring is required.

Start the motor and put the head of the tachometer in the center hole of the motor shaft, and the measured data is the number of revolutions.

What speed do you want, how complete is the answer on the first floor.