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In general, two contactors are required for normal rotation is a three-phase AC asynchronous motor. Due to the three-phase AC asynchronous motor, when the phase sequence of the power supply is turned down, it will be rotated. The phase sequence of the power supply is turned off, which is to allow any two phase wires in between. The azimuth inversion is good, for example, the azimuth inversion between the AB phases can be rotated. To complete this arbitrary two-phase inversion, two contactors are required. This is a three-phase asynchronous motor. The left side is the main circuit. After the two contactors are phase-adjusted to complete the positive rotation, for example, when the KM1 is closed, the three-phase power ABC is connected to the three terminals of the motor in sequence. At this time, the motor It's true. When KM2 is pulled in, the three phases of the power supply are connected to the three terminals of the motor according to the BAC sequence. At this time, the motor has completed the turning function. On the right is the control circuit of the two contactors. It is an interlock circuit and a self-protection circuit, and there is also a fuse. KM1 and KM2 cannot be connected together, otherwise there is a danger of short circuit, so the auxiliary contact of the two contactors is used in series with each other's coil. In this way, one contactor is energized and will prevent the other one

The contactor is charged again. There are two forward switches in the loop, but only one stop button is required. Fan system Single-phase motors complete the forward rotation by switching the orientation between the starting capacitor and the main and auxiliary windings. This will form two types of magnetic fields, SNSN and NSNS. Of course, it can also achieve similar interlocking through two contactors or relays. Circuit-controlled. In fact, the two main contacts of the contactor are used to switch the capacitor in series between the main winding and the secondary winding through the main contacts of the two contactors, so that the direction of the magnetic field can be changed and the positive rotation can be completed.

As for the control circuit, it is the same as the three-phase asynchronous motor, and it is also a self-protection and interlock circuit. As for DC motors, servo motors, or stepper motors, there are usually corresponding controllers to control them. It may be better to give a negative signal on the controller through a similar start-stop switch. Of course, there is a brushed DC motor, which can also complete the forward rotation by switching the square armature of the armature or the current through the contactor.

Generally, the working temperature range of stepper motor is 0 ~ 50 u0026 deg ;, humidity 20% ~ 90% RH; storage temperature range is -20 ~ 70 u0026 deg ;, humidity 15 ~ 95% RH. The environmental requirements for the use of stepper motors are described as follows: About temperature requirements. Some stepper motors have insulation material standards of ULB level, which means that the temperature resistance of the motor insulation system is within 130 u0026 deg ;, taking into account the temperature difference between the inside and outside of the motor and the safety factor Therefore, it is required that the surface temperature of the motor is lower than 100 degrees. Considering that the general room temperature is within 40 u0026 deg ;, the temperature rise of the motor coil is required to be controlled within 80K. If the temperature of the motor coil exceeds the limit temperature of the insulation system, it is easy to burn out the insulation system such as the motor coil enameled wire and the insulation slot, PCB board, etc., causing the motor to fail (generally open circuit, but also short circuit phenomenon). The parameter of the rated current of the motor is mainly calculated based on the heat generation that the motor can withstand. If the working environment temperature of the motor is relatively high, it is necessary to consider reducing the working current of the motor to reduce the temperature rise, and finally control the internal heating of the motor within the range that the insulation system can withstand. For example, if the ambient temperature is 60 u0026 deg ;, the temperature rise of the motor must be controlled within 60K. Because the insulation materials of most stepper motor manufacturers are B-level standards, higher-level insulation materials are almost impossible to correspond or the cost is too high. Therefore, in applications where the working environment temperature is relatively high, the more realistic choice is control The temperature rise of the motor is realized by strengthening the heat dissipation conditions or reducing the working current of the motor. The temperature of the stepping motor is too high, in addition to affecting the safety of the insulation system, it will also affect the stability of the permanent magnet. The permanent magnet will demagnetize as the temperature rises, which will reduce the working torque of the motor. The demagnetization factor of the Shinano stepper motor's magnet within 130 u0026 deg; can be ignored, but some manufacturers' magnets have obvious torque attenuation problems even within the range of problems that the insulation system can withstand.

The temperature of the stepping motor is too low, which will cause the bearing grease to solidify, thereby losing the lubricating effect of the bearing. Therefore, it is necessary to consider the use of low temperature bearings when the temperature is lower than 0 degrees. If the customer electrifies the motor to heat it up before the motor works, it is acceptable to let the motor rotate after reaching the required operating temperature of the motor, but the device's startup process should be set accordingly. If low temperature resistant bearings are used, the general motor allows the working temperature of the stepper motor to reach -45 u0026 deg ;, but the motor needs to be customized. Shinano generally does not make this kind of customized product and requires Fan system another manufacturer to customize it. Requirements on humidity The requirements of stepper motors on humidity are mainly to avoid condensation in the motor. The silicon steel sheet on the outer surface of the rotor of the stepper motor and the inner surface of the stator generally has no other measures to prevent rust than applying anti-rust oil during processing. If the humidity is too high, it is easy to condense on the surface, causing rust. Because the gap between the rotor and the stator of the stepping motor is very small, rust spots are likely to jam the rotor and cause the motor to fail. On the other hand, the humidity is too high, which will also affect the insulation characteristics of the insulating material. Generally, it has little effect on small stepper motors with low working motors, but it does not affect stepper motors with high driving voltages. Can be ignored. Reference: Grade description of heat-resistant material for motor insulation material.

UL divides the certification level of the insulation system from low to high according to heat resistance temperature: Y A E B F H C level. The following is a brief description of the maximum allowable operating temperature (° C) of the heat-resistant grade for the insulation material equivalent to the heat-resistant grade. Y-class temperature resistance 90 u0026 deg ;, an insulation structure composed of unimpregnated cotton yarn, silk, paper and other materials or their combinations. Therefore, Y-grade materials can do the job without any treatment.级 Class A temperature resistance 105 u0026 deg ;, insulation structure composed of materials impregnated or immersed in liquid dielectric (such as cotton yarn, silk and paper in transformer oil, or combinations thereof). Class E temperature resistance 120 u0026 deg ;, insulation structure composed of synthetic organic film, synthetic organic enamel and other materials and its composition, class B temperature resistance 130 u0026 deg ;, bonded or impregnated with suitable resin, coated mica, glass fiber, Asbestos, etc., as well as other inorganic materials, suitable organic materials or combinations of insulating structures. F-class temperature resistance 155 u0026 deg ;, Insulating structure composed of mica, glass fiber, asbestos, etc. bonded or impregnated with suitable resin, coated with other inorganic materials, suitable organic materials, or combinations thereof H-class temperature resistance 180 u0026 deg ;, an insulating structure composed of mica, glass fiber, asbestos and other materials or a combination thereof bonded or impregnated with a suitable resin (such as a silicone resin).级 C-class insulation temperature of 180 or more, with suitable resins bonded or impregnated, coated mica, glass fiber, and non-impregnated mica, ceramics, quartz and other materials or combinations of insulating structures. The above is an introduction to the working temperature and humidity of the stepper motor. I hope that friends who can help can help.