Silicon controlled rectifiers (SCR) are widely used thyristors for large drives of DC motors in the power conversion unit. An SCR conducts when a small voltage is applied to its door terminal. Its conduction continues until the beginning of the negative cycle and automatically turns off as soon as the voltage passes through the SCR to the next closed signal through the natural zero point. I can know the advantages and disadvantages of driving the DC motor and driving the AC motor On the input side, an AC drive is similar to a DC drive in that an alternating current (AC) input is regulated in direct current by SCR or a simple bridge rectifier. This DC output would be half a cycle depending on the AC input phase frequency, so AC drives use a bank of capacitors to stabilize and smooth this DC voltage. In the output area of the drive, the motor is then powered by means of 6 output transistors or IGBT modules. Simply put, the reader converts the AC input current to direct current and converts this direct current back into alternating current to power the motor. The error is amplified by the cruise control (which is essentially a speed error amplifier) and its output is given as the current input reference for the internal control system. As the current reference increases, the internal current regulator drives more current to the motor, providing additional torque. The internal current loop is responsible for maintaining the zero current error between the actual current of the motor and the current reference signal, which means that the actual current of the motor follows the reference current.
The amplified current fault signal of the current regulator controls the angle of fire of the bridge and therefore the output voltage of the converter. Current feedback is provided either by an DC transformer or by an AC transformer (with rectifier) in the main supply lines. Of course, AC drives (VFDs) and AC motors now offer an alternative to DC drives and motors, but there are many other applications where DC drives are widely used, including cranes and hoists, elevators, spindle drives, reels, paper production machines, crushers, etc. because of the advantages of DC workouts. This drive can be used in an open control loop without feedback and can achieve a speed control of 5-8%. However, in many applications, a speed control of less than 5% is required. In such cases, the unit of measurement/scaling of the speed passes to the EMF feedback measurement circuit. We offer a wide range of equipment services such as the overhaul of an AC or DC traction motor, a BT motor winding or the post-processing and reprocessing of components. The combination of in-depth technical know-how and first-class engineering ensures reliable quality and delivery. We operate: DC drive technology is efficient, reliable, cost-effective, user-friendly and relatively easy to implement. DC drives offer many advantages over frequency converters, especially for regenerative and high-performance applications. DC drives are widely used in industrial drive applications to enable highly precise control.
Ignition Circuit: It provides the grid pulses with the thyristors, so they are turned on for certain periods of time to create a variable reinforcement voltage. Insulation is also provided in this door drive circuit. Although DC drives are known to provide high starting torque, have simple circuits, and are well suited for constant speed applications, they are also thought to have more problems, especially due to the requirement for switches and brush assemblies in DC motors (which require a lot of maintenance, can wear out over time, and often have mechanical problems). On the other hand, frequency converters are more energy autonomous and can better cope with the rapid shifts due to the operation of induction motors. They often have hundreds of different programmable parameters for fail-safe protection. While this makes the AC player more complicated in many ways, advances in programming software provided by drive manufacturers are making installation and use easier than ever. This drive also contains a separate field strainer for field control (via rated speeds). A field current controller in the microprocessor determines the voltage of the field windings by accepting the operator`s flow/field reference signal. This regulator provides the ignition signals needed by the field converter unit to generate the required DC voltage proportional to the speed. For permanent magnet DC motors, the field power unit is not included in the drive.
Rectifier Bridge: The power component of a regulated DC drive is a full shaft bridge rectifier that can be driven by a three-phase or single-phase power supply. As mentioned above, the number of thyristors may vary depending on the supply voltage. In modern microprocessor digital drives, speed control is carried out with a research table to determine the current of the combustion circuit with additional digital circuits. BIT 802E provides Ethernet control and full control over bipolar output, either via a web page with a browser or by using SCPI commands via Telnet. A standard analog DC player with speed and current control is shown in the following figure. The purpose of this system is to provide speed control, and therefore the speed reference is used for the input into the system and the motor speed is the output of the system measured by the tachometer. With advances in digital control, DC discs are becoming more flexible and faster (due to faster response times) compared to analog drives. .