Drive or Electric Drive is an electromechanical system that necessarily uses an electric motor or a prime mover. In this system, the motion of the electric motor is controlled to make it applicable and useful for some applications in the realm of industry, automotive, domestic use, hospitals, etc. In an electric drive system, energy conversion is controlled. Motor, control systems and power converter (power electronics) are major components of electric drive. The selection or construction of various drive components varies depending upon the application and environment where the system is to be used. DC bus is part of the power electronics part of the drive. Its stability and voltage control are crucial to gaining good results for the drive system. The Drive system is a complex electrical system. As mentioned earlier, the following are its major components Electric Motor Controller Power Converter or Power Electronics Section These three components are complex systems in themselves...
Drives that control motor speed such as Variable Frequency Drives (VFDs), AC Drives, and Variable Speed Drives (VSDs) include a rectifier unit, in which the AC voltage is supplied to the drive is converted into DC voltage. In most of these motor drives, this rectifier unit makes use of standard P-N junction diodes (two-layer diodes) to build different types of rectifier circuits like half-wave, bridge, and full-wave rectifiers. However, if high voltage is applied to any of these two-layer diode rectifiers, its diodes are likely to get damaged. For this reason, motor drives using rectifier units made of P-N junction diodes cannot operate reliably at high supply voltages. To overcome this limitation, a special type of rectifier that could withstand high voltages was developed. This rectifier is the Silicon Controlled Rectifier (SCR). SCRs are often used in applications where a large amount of power needs to be switched, though it’s necessary to keep their control voltage and current low...
In industrial automation, the term “drive” is often associated with motor drives, which are types of motor controllers described using various terms such as Variable Speed Drives (VSDs), Adjustable Speed Drives (ASDs), Inverter Drives, Adjustable Frequency Drives (AFD), Variable Frequency Drives (VFDs), AC Drives, Variable-Voltage Drives, …etc. However, even though these terms are used interchangeably, they have different meanings depending on the technique used to control the motor speed and the drive’s application. For example, a Variable Speed Drive is a more generic term that applies to electronic or mechanical devices which control either motor speed or the speed of motor-driven equipment like compressors, fans, pumps, etc. Whereas, a VFD is a device that uses power electronics to vary the frequency of the input voltage to a motor, thereby controlling the motor speed. On the other hand, an Adjustable Speed Drive is also a more generic term that applies to both electrical and...
Allen Bradley MPL Servo Motors A servo motor is a linear or rotary actuator that allows for precise control of linear or angular position, acceleration, and velocity. A typical servo motor system consists of a suitable electric motor coupled to a sensor for position feedback. The motors’ control circuit, which includes the position sensor, provides feedback on the real-time position of the motor shaft. With this feedback, the servo motor can rotate with great precision. But for a servo motor system to be complete, it also requires a servo drive that uses the position feedback sensor to precisely turn the servo motor at some specific angles or distances. Simply put, a servo motor is just a simple electric motor that runs through a servo mechanism. Servo motors are broadly categorized as AC-powered or DC-powered. But there are many other classifications depending on the operating characteristics and gear arrangement of the servo motor in question. The different types of gear...
A Variable Frequency Drive (VFD), also known as a Variable-Speed Drive (VSD), Adjustable-Frequency Drive (AFD), Frequency Converter (FC), Adjustable Speed Drive (ASD), Microdrive, AC drive, or an Inverter driver, is an electronic controller used to regulate the rotational speed of induction or synchronous electric motors. The VFD controls motor speed by varying the frequency of the supply voltage being used to power that motor. To practically execute this, a typical VFD system consists of four main components; namely, the Rectifier Circuit unit, DC Bus and Filter unit, Inverter Circuit unit, and the control unit. These four units function together to adjust the AC frequency of the voltage supplied to a connected motor, thereby controlling the motor’s RPM (motor speed in revolutions per minute). First, the VFD takes in fixed frequency AC voltage into the rectifier section, which consists of diodes (4 or 6) or thyristors that convert the input AC voltage into unfiltered DC voltage. This...
Programmable Logic Controllers are ruggedized computers, specially designed and built to operate reliably under harsh industrial environments. A typical PLC system consists of a processor (CPU), programmable memory, power supply, a user-defined program, I/O modules with associated circuitry, and so on. The programmable memory stores a series of instructions that enable the PLC to perform various control functions like arithmetic computation, relay logic, timing, counting, and sequencing. Essentially, these control functions are used to monitor and control either individual machines or complex electro-mechanical processes through the PLC inputs and outputs. As the PLC processor reads the inputs, the PLC processes them through the stored user-defined program and generates outputs that are sent out as control commands to field output devices. The I/O modules in the PLC system provide digital or analog electronic connections to field input and output devices. In this modern era, PLCs are...
VersaView and PanelView are Allen-Bradley operator interfaces from Rockwell Automation, with similar functionalities as Human-Machine Interfaces (HMIs). These graphic operator terminals combine HMI software and hardware to allow users to interact with a controller and the system being controlled. An HMI terminal can vary from a physical control panel with indicator lights and keypad buttons to an industrial PC (IPC) with color graphic displays and which runs a dedicated software. The Allen-Bradley PanelView and VersaView are both popular operator terminals in a variety of industrial control applications requiring the display of information graphically, real-time monitoring, and control of various industrial processes. They enable operators to understand the status of a controller fast enough, so as to make informed control decisions regarding the machine or process being controlled. Allen-Bradley PanelView Terminal Allen-Bradley PanelView terminals provide rugged, graphical interface...
In general, the concept of Sourcing and Sinking details a current flow relation between input and output devices of a control system and their power supply. This concept is based on the basic electrical theory, which states that; to complete an electrical circuit, the conventional current should flow from the DC+ terminal through a load to the DC- terminal. In that regard, the two terminologies (Sinking and Sourcing) apply only to DC input and DC output circuits. And not to AC circuits because of the reference to positive (+) and negative (-) polarities. In PLC systems, the Sinking and Sourcing concept may be confusing to most people but it’s fairly a simple one. As Sink and Source logic circuits are mainly associated with digital PLC Input and Output (I/O) signals. A logic circuit is basically an electrical I/O circuit in which its output is a function of the input. Such circuits are defined by the type of components used and the direction of current flow. A simple logic circuit can...
VFDs or Variable Frequency Drives are controller systems including motors that give varying output speed as per input command. The capacitor forms DC links the whole VFD system. The voltage across this DC link is an important parameter to be controlled. This voltage is input to the inverter and thus acts as a reference voltage in the system. Variations in DC link voltage or voltage across the capacitor impacts the speed and performance of motor greatly. The selection of capacitor is equally important as its size will define the ripple factor, noise, and smoothness in the running of the motor. While it is important to know the significance and working of capacitors in a drive system, let’s understand the basics of the drive system, associated terminologies, and common topologies. To understand the purpose of capacitors in VFDs, one should have an idea of the purpose of VFDs and their basic work topology. Variable Frequency Drives are electromechanical systems in which the speed and...
The term VFD stands for Variable Frequency Drive. It is a type of motor controller which drives an electric motor by varying the frequency and voltage supplied to that motor. Variable Frequency Drives (VFDs) are also known as AC Drives, Inverters, Variable/Adjustable Speed Drives, Inverters, Variable-Voltage Drives, Microdrives, Frequency Converters, or Variable Frequency Inverters (VFIs). Frequency, given in Hertz (Hz), is directly related to motor speed in revolutions per minute (RPM). Thus, by adjusting the input frequency the motor speed can be varied accordingly. For example, the higher the supply frequency, the more RPMs the motor will exhibit. VFDs are best suited for applications in which an electric motor is not required to run at full speed, as they can ramp down the supply voltage and frequency to meet the requirements of the motor’s load. In case there is a change in the application’s motor speed requirements, the VFD can be set to ramp up or turn down the motor speed as...
An MP-Series Low-Inertia Servo Motor (Cat. No. MPL-B320P-MJ22AA) MPL servo motors are a family of MP-Series™ low-inertia rotary servo motors, from Rockwell Automation under Allen-Bradley Bulletin MPL. They are compact and highly dynamic brushless servo motors consisting of premium permanent magnets. They feature multi-turn or single-turn high resolution encoders, and they are available with 24 Volts DC brakes. The MPL units use innovative design characteristics and advanced winding technology to reduce motor size while delivering considerably higher torque. They thus leverage their high torque-to-size ratio to provide high-performance motion systems, which require servo motors with quicker acceleration and excellent torque performance. The MP-Series™ low-inertia servo motors are typically used with PowerFlex drives and Kinetix drives from Allen-Bradley. The Allen-Bradley® MPL servo motors feature two input voltage classes: 400V-class and 200V-class. They are available in nine (9)...
Allen Bradley PowerFlex4 The Allen-Bradley PowerFlex 4 is a series of compact Variable Frequency Drives (VFDs), which provide powerful and precise motor speed control. These drives are programmed for Volts-per-Hertz (V/Hz) operation mode, as the default motor control setting. They are designed for ease of use and optimal flexibility, with a space-saving design. In addition, PowerFlex 4 drives provide users with intuitive interface devices including an integrated keypad with control keys and a local potentiometer. Moreover, the PowerFlex 4 drives are an economical speed control alternative for a variety of industrial applications including fans, conveyors, machine tools, pumps, and material handling systems. Essentially, PowerFlex 4 drives are designed to meet the demands of global Original Equipment Manufacturers (OEMs) and end-users for simplicity, cost efficiency, and space savings. They are the smallest and most cost-effective members of the compact, Allen-Bradley PowerFlex®...
The Allen-Bradley PowerFlex® is a family of Compact-class AC drives developed by Rockwell Automation, to deliver cost-effective solutions for simple system integration or standalone machine-level control applications. In general, PowerFlex drives provide extreme application flexibility, linear scalability, and excellent performance while simplifying the management of workload infrastructure. PowerFlex 40 and 40P drives are the most compacts and cost-effective members of the Allen-Bradley PowerFlex® series of AC drives. They are a general-purpose class of AC drives, which provide a compact package to optimize application versatility and panel space. They are designed for ease of use, providing users with powerful and dynamic motor speed control in a compact, space-saving design. This article seeks to provide an in-depth comparison of the features and control capabilities of PowerFlex 40 and PowerFlex 40P AC drives. Allen Bradley PowerFlex 40 Allen-Bradley PowerFlex® 40 drives are an...
Allen-Bradley PanelViews are graphical operator interfaces, similar to Human-Machine Interfaces (HMIs). They are a combination of hardware and software through which users interact with a controller. These PanelView terminals are popular in a variety of industrial applications that require monitoring, control, and graphical display of operational data. Their color graphics displays allow operators to quickly understand the status of the controller and the system or machine being controlled, to make better control decisions. However, with so many different PanelView terminals available from Rockwell Automation, selecting the right one for your application can be confusing especially if you’re not familiar with their features. This article seeks to provide a detailed comparison of PanelView 800 and PanelView plus 7, to hopefully assist you to make a more informed choice between the two. PanelView 800 PanelView 800 terminals are color graphic Human-Machine Interface (HMI) devices under...
Allen Bradley’s PowerFlex 750 series of alternating current drives are available in a variety of enclosure ratings to meet a wide range of requirements as per the user’s application. It’s critical to pick the correct enclosure ratings for your drive since you don’t want your system to go down or production to be affected if your drive fails. Enclosures for drives are evaluated according to their compatibility for specific applications and how well they shield equipment. A number is assigned to each type of enclosure depending on its capacity to bear up environmental factors. For this drive’s series, enclosures have Ingress Protection (IP), NEMA, and UL Type classifications. We will look into the details of these standards, so you’ll know precisely what to look for while selecting a drive from the PowerFlex 750 series. We’ll only concentrate on available enclosures for these drives in this guide. Then, we will discuss possible enclosure codes – a combination of NEMA, IP, and UL...