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3 phase motor ka data kaise nikale electric dynamo motor for free energy generator

3 phase motor ka data kaise nikale electric dynamo motor for free energy generator

2. AC motor speed regulation:

(1) Three phase asynchronous motor:

a. Variable pole pair speed regulation method: change the stator winding connection mode to change the stator pole pair of cage motor to achieve speed regulation. Features: hard mechanical properties, good stability; No slip loss, high efficiency; Simple wiring, convenient control and low price; There are stages for speed regulation, and the stage difference is large, so smooth speed regulation cannot be obtained; It can be used in combination with pressure regulation and speed regulation and electromagnetic slip clutch to obtain smooth speed regulation characteristics with high efficiency. This method is applicable to production machinery without stepless speed regulation, such as metal cutting machine tools, elevators, lifting equipment, fans, water pumps, etc.

b. Variable frequency speed regulation: it is a speed regulation method that changes the frequency of the motor stator power supply, thereby changing its synchronous speed. The main equipment of the variable frequency speed regulation system is the frequency converter that provides variable frequency power. The frequency converter can be divided into AC DC AC frequency converter and AC AC frequency converter. At present, most of the domestic use AC DC AC frequency converter. Its features: high efficiency, no additional loss during speed regulation; Wide range of applications, can be used for cage asynchronous motor; Large speed regulation range, hard characteristics and high precision; Complex technology, high cost and difficult maintenance. This method is suitable for occasions requiring high precision and good speed regulation performance.

c. Cascade speed regulation: adjustable additional potential is cascaded into the rotor circuit of wound motor to change the slip of motor and achieve the purpose of speed regulation. According to the slip power absorption and utilization mode, cascade speed regulation can be divided into motor cascade speed regulation, mechanical cascade speed regulation and thyristor cascade speed regulation. Thyristor cascade speed regulation is mostly used. Its characteristics are: the slip loss in the speed regulation process can be fed back to the power grid or production machinery, with high efficiency; The capacity of the device is directly proportional to the speed regulation range, which saves investment. It is suitable for production machinery whose speed regulation range is 70% - 90% of the rated speed; When the speed regulating device fails, it can be switched to full speed operation to avoid shutdown; The power factor of thyristor cascade speed regulation is low, and the harmonic influence is large. The method is suitable for fans, water pumps, rolling mills, mine hoists and extruders.

 

3 phase motor ka data kaise nikale electric dynamo motor for free energy generator

d. Additional resistance in series: the rotor of wound asynchronous motor is connected with additional resistance in series to increase the slip rate of the motor and the motor operates at a lower speed. The greater the series resistance, the lower the speed of the motor. This method has simple equipment and convenient control, but the slip power is consumed on the resistance in the form of heating. It is a step-by-step speed regulation with soft mechanical characteristics.

e. Stator voltage regulation and speed regulation: since the torque of the motor is proportional to the square of the voltage, the maximum torque decreases a lot. In order to expand the speed regulation range, cage motors with large rotor resistance should be used for voltage regulation and speed regulation, such as torque motors specially used for voltage regulation and speed regulation, or frequency sensitive resistors should be connected in series on wound motor. In order to expand the stable operation range, feedback control should be adopted when the speed regulation is above 2:1 to achieve the purpose of automatic speed regulation. The main device of voltage regulation and speed regulation is a power supply that can provide voltage changes. At present, the commonly used voltage regulation methods include series saturated reactor, autotransformer and thyristor voltage regulation. Thyristor voltage regulation mode is the best. Characteristics of voltage and speed regulation: the voltage and speed regulation circuit is simple and easy to realize automatic control; In the process of voltage regulation, the transfer differential power is consumed in the rotor resistance in the form of heating, and the efficiency is low. Voltage and speed regulation is generally applicable to production machinery below 100kW.

f. Electromagnetic speed regulation: features: simple device structure and control circuit, reliable operation and convenient maintenance; Smooth and stepless speed regulation; No harmonic influence on power grid; Large speed loss and low efficiency. This method is applicable to medium and small power production machines that require flat sliding and short-term low-speed operation.

3 phase motor ka data kaise nikale electric dynamo motor for free energy generator

g. Hydraulic coupling speed regulation: features: large power adaptation range, which can meet the needs of different power from tens of kilowatts to thousands of kilowatts; The utility model has the advantages of simple structure, reliable operation, convenient use and maintenance, and low cost; Small size, large capacity; Convenient control and adjustment, easy to realize automatic control. This method is applicable to the speed regulation of fans and pumps.

(2) Single phase asynchronous motor: (compared with torque motor, it has constant torque; compared with variable frequency motor, it does not save energy; compared with DC motor, its control accuracy is low;)

Single phase asynchronous motor and three-phase asynchronous motor, its speed regulation is difficult. If variable frequency speed regulation is adopted, the equipment is complex and the cost is high. For this reason, only polar speed regulation is generally carried out. The main speed regulation methods are:

a. Series reactor speed regulation (step-down speed regulation): connect the reactor in series with the motor stator winding, and use the voltage drop generated on the reactor to make the voltage added to the motor stator winding lower than the power supply voltage, so as to achieve the purpose of reducing the motor speed. This speed regulation method can only be adjusted from the rated speed of the motor to low. It is mostly used on ceiling fans and table fans.

b. Internal tap speed regulation of motor winding: change the wiring method of intermediate winding, starting winding and working winding through speed regulation switch, so as to change the size of air gap magnetic field inside the motor and achieve the purpose of adjusting motor speed. There are L-type and T-type connections.

c. AC thyristor speed regulation: by changing the conduction angle of the thyristor, the AC voltage applied to the single-phase motor can be adjusted to achieve the purpose of speed regulation. This method can realize stepless speed regulation, but it has some electromagnetic interference. It is often used in the speed regulation of electric fans.

5、 Motor start

1. DC motor start

(1) Startup method

Direct closing and starting: direct closing and starting is to connect the motor directly to the power supply of rated voltage for starting. Because the armature circuit resistance and inductance of DC motor are small, and the rotating body has certain mechanical inertia, the current at the beginning of starting is very large, up to 15 ~ 20 times of the rated current. Because the starting current of the motor is very large, the starting torque is large and the motor starts quickly, but this current will disturb the power grid, mechanically impact the unit and spark the commutator. It is only applicable to small motors with a power not greater than 4 kW, such as DC motors in household appliances.

Series resistance starting: during starting, a group of starting resistors RP are connected to the armature circuit to limit the starting current. When the number of revolutions rises to the rated number of revolutions, the starting rheostat is removed from the armature circuit. The starting current is small, but the rheostat is bulky, which consumes a lot of energy in the starting process.

3 phase motor ka data kaise nikale electric dynamo motor for free energy generator

Voltage reduction starting: during starting, the starting current is limited by temporarily reducing the motor supply voltage. A set of variable voltage DC power supply is required. This method is only suitable for high-power DC motors.

(2) Starting torque

The starting torque of the DC motor is set by yourself. If you start directly at full voltage, it can reach more than 20 times of the rated torque, which will damage the machinery. Therefore, you must add the starting resistance to reduce the starting current, so as to reduce the starting torque. Generally, the added starting resistance makes the starting torque about 2-2.5 times of the rated torque, so that the motor and machinery can bear it and the starting process can be accelerated.

2. AC motor start

(1) Startup method

Full voltage start-up: full voltage direct start-up can be considered when both grid capacity and load allow full voltage direct start-up. The utility model has the advantages of convenient operation and control, simple maintenance and economy. It is mainly used for starting small power motors. From the perspective of saving electric energy, this method is not suitable for motors larger than 11kw.

Autotransformer reduced voltage starting: the multi tap reduced voltage of autotransformer can not only meet the needs of starting with different loads, but also obtain greater starting torque. It is a reduced voltage starting method often used to start large capacity motors. Its biggest advantage is that the starting torque is large. When the winding tap is at 80%, the starting torque can reach 64% of the direct starting torque. And the starting torque can be adjusted by tapping. It is still widely used today.

Y- Δ Starting: the normally operating stator winding is a squirrel cage asynchronous motor with delta connection. During starting, the stator winding is connected into a star and then into a triangle after starting, so as to reduce the starting current and reduce the impact on the power grid. The starting current is only 1/3 of the original direct starting according to the triangle connection method, and the starting torque is also reduced to 1/3 of the original direct starting according to the triangle connection method. It is suitable for no-load or light load starting. Compared with any other pressure reducing starter, it has the simplest structure and the cheapest price. In addition, when the load is light, the motor can run under the star connection method, which can improve the efficiency of the motor and save power consumption.

Soft starter: the phase-shifting voltage regulation principle of thyristor is used to realize the voltage regulation and starting of motor. The starting effect is good but the cost is high. The thyristor has large harmonic interference when it works, which has a certain impact on the power grid. In addition, the power grid fluctuation will also affect the conduction of thyristor components, especially when there are multiple thyristor devices in the same power grid. Therefore, the failure rate of thyristor components is high, because it involves power electronics technology, so the requirements for maintenance technicians are also high.

Frequency converter: because it involves power electronics technology and microcomputer technology, the cost is high and the requirements for maintenance technicians are high. Therefore, it is mainly used in the fields requiring speed regulation and high requirements for speed control.

In short, star delta starting and self coupling reduced voltage starting still occupy a large proportion in practical application because of their low cost, relatively easy maintenance of soft starting and variable frequency control. However, because it is assembled with discrete electrical components and there are many control line contacts, the failure rate is relatively high in its operation.

 

3 phase motor ka data kaise nikale electric dynamo motor for free energy generator

(2) Starting torque

The starting torque represents the starting capacity of the motor. The starting torque is greater than the rated torque. Generally, the relationship (multiple) between the two is marked on the motor template, which is about 2 times. It is related to the starting mode (such as star delta starting, variable frequency speed regulating starting, etc.). The direct starting squirrel cage type is generally 0.8 to 2.2 times of the rated torque. Generally, the starting torque is more than 125% of the rated torque. The corresponding current is called starting current, which is usually about 6 times of the rated current. Generally, there are two groups of autotransformer taps: 65% and 80%. When a large starting torque is required, connect 80%, otherwise connect 65%;

6、 Motor braking

1. Reverse braking:

After the motor is disconnected from the power supply, add a power supply opposite to the normal operation power supply to the motor power supply to speed up the motor deceleration. Reverse braking has one biggest drawback: when the motor speed is 0, if the reverse phase power supply is not removed in time, the motor will reverse. Therefore, for machines that do not allow reverse rotation, such as some lathes, the braking method cannot adopt reverse braking, but only energy consumption braking or mechanical braking.

Energy consumption braking:

Direct current is applied to the stator winding to generate a fixed magnetic field. The rotor cuts the magnetic lines of force according to the rotation direction to generate a braking torque. Since the stator winding is braked by DC, energy consumption braking is also called DC injection braking. In some occasions requiring short braking time and good braking effect, this braking method is generally not used.

3. Regenerative braking:

When the rotor speed of the motor exceeds the rotation speed of the synchronous magnetic field of the motor, the rotation direction of the electromagnetic torque generated by the rotor winding is opposite to that of the rotor, and the motor is in the braking state. At this time, certain measures can be taken to feed back the generated electric energy to the power grid. Therefore, regenerative braking is also called generation braking. Regenerative braking can occur in the following two occasions: 1. When the weight of the crane drops, the rotor speed may exceed the synchronous speed under the manual operation of the weight. At this time, the motor is in the regenerative braking state. 2. During variable frequency speed regulation, when the frequency converter reduces the frequency, the synchronous speed also decreases. However, the rotor speed will not decrease immediately due to the load inertia. At this time, the motor will also be in the regenerative braking state until the speed of the driving system also decreases.

4. Mechanical braking

The braking method of quickly stopping the motor after disconnecting the power supply by mechanical device. Such as electromagnetic holding brake, electromagnetic clutch and other electromagnetic brakes.

7、 Servo motor

1. DC servo motor and DC brushless motor

Brushless DC motor and DC servo motor are two types, and there is no intersection in concept. In short: DC servo motor refers to DC brush motor. The brushless motor has the advantages of small volume, light weight, large output, fast response, high speed, small inertia, smooth rotation and stable torque. The control is complex and easy to realize intellectualization. Its electronic commutation mode is flexible and can be sine wave commutation. The motor is maintenance free, with high efficiency, low operating temperature, low electromagnetic radiation and long service life. It can be used in various environments.

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