Advantages of an AC Servo Motor

At factories, mills and pressing plants, motorized machines are called upon for a vast array of critical operations. Whether you run a production line of mass-assembled products or facilitate a public utility, the operations that you oversee rely on high-powered motors that can run without fail throughout lengthy work shifts for days, months and years on end, in some cases 24/7.

When you consider the amount of time and money that depends on a perfect outcome with each application, it becomes clear how crucial it is that your motors operate reliably. Therefore, each machine and tool must be equipped with a motor specially designed for the high-speed, high-powered applications at hand. For the vast majority of industrial applications, servo motors are the answer.

About Servo Motors

Servo motors are the mechanical components utilized for automatic control systems. The servo is a tiny component with an output shaft. The servo offers controlled precision for high-velocity, thanks to the design of the actuator. When the motor receives a signal, it accelerates the velocity of operations as dictated by the user or engineer. If the purpose of a mechanical system is to determine the placement of a particular object, that system is referred to as a servomechanism.

Servo motors come in two basic types: AC and DC. Each type is designed for a different range of applications, but both can be found in various industrial and domestic machines and devices.

AC Servo Motors vs. DC Servo Motors

The difference between AC and DC servo motors boils down to electrical currents and the unique way that the current works in each motor type. Due to these differences, each motor is suited to somewhat different applications. While the applications of both AC and DC motors are regularly encountered in daily activities, the functions of AC motors are generally more prevalent in people’s domestic and work lives.

AC Servo Motor Features

In an AC servo motor, you have an alternating current (AC) that functions in reverse order. Each second, the current alternates numerous times. Alternating currents are facilitated by a transformer device that moves currents of power across vast distances at high voltages. The AC servo motor can handle changing voltages with greater ease than a DC servo motor.

AC servo motors run on the AC voltage outlets that are typically found in homes and office buildings. As such, AC motors are commonly used in a vast range of machinery. To get a machine or device to run when you press the power-on button or flip the activation switch, the nearest outlet makes it all possible thanks to an AC motor.

The two principle kinds of AC motors are synchronous and induction. An induction AC motor is an asynchronous motor that relies on a speed discrepancy between the rotations of the magnetic field and shaft. A synchronous AC motor, by contrast, uses permanent magnets and yields a rated torque at a precise synchronous speed. The average two-phase AC servo motor features a squirrel-cage rotor and a control winding fed by a power amplifier.

In a synchronous AC servo motor, the rotor speed correlates to the stator, as the two spin round in sync with one another. Synchronous AC motors are valued for their ability to activate vast mechanical systems with maximum efficiency. For machines and devices in which accuracy is of the utmost importance, synchronous motors are especially common. Examples of items that typically contain synchronous AC motors include alarm clocks, metering pumps, factory robots and speed controllers. Synchronous AC motors are the critical, active component in drill machines and other high-precision tools.

Induction AC motors are the most widespread motor type found in everyday devices. The rotation speed of an induction motor correlates to the frequency of the corresponding current. In the majority of processes, induction AC motors are used for applications that demand vast amounts of heat and pressure. Examples of machines that run on induction AC motors include kitchen appliances like dishwashers and ovens. Induction motors are also used at industrial facilities to run boiler pumps and water pumps. In buildings, induction motors are responsible for the operation of fans and air conditioners.

DC Servo Motor Features

In a DC servo motor, you have a direct current (DC) with a positive and negative terminal. Between each of these terminals, the current flows in the exact same direction. The current passes through coils between the commutator and brushes. The brushes inside the motor need to be replaced regularly. However, the life of these brushes can be prolonged with periodic maintenance.

With a DC servo motor, current control is far simpler than with an AC servo motor because the only control requirements are in the current armature magnitudes. The motor speed is operated by duty-cycle controlled pulse width modulation (PWM). Control flux is used to manage torque, which allows for reliable consistency throughout each active cycle.

Advantages of AC Servo Motors Over DC Servo Motors

AC motors remain popular more than a century after they were first invented because the design principle is just as relevant today as it was more than a century ago. Many modern-day machines operate on the same principles that formed the basis of the first AC induction motor developed by Nikola Tesla in 1887.

Over the decades, AC motors have lasted because their durability and versatility have made them adaptable to successive generations of technology. The following list of AC servo motor advantages illustrates the reasons for the motor’s widespread use and ongoing popularity:

1. Efficiency

The AC motor offers maximum efficiency for numerous applications because of its unique speed-to-torque capability, which makes it possible to run assorted applications with minimal heat, wear or degeneration. As such, AC motors are often chosen for the various machines that comprise the vast industrial arsenals at factories and pressing plants.

2. Longevity

AC motors are built for long-lasting performance in some of the most challenging applications. In an AC motor, there are few moving parts. When the motor is active, the relative lack of moving metal parts allows for slower wear and a low probability of sudden failure. These traits give AC motors extended longevity, which makes this motor type ideal for field applications in which machines and vehicles are expected to perform for hours on end, far away from repair facilities.

By the same token, the longevity of the AC motor makes it the ideal motor type for machines and appliances that are used daily in the service industry, such as cappuccino makers and vending machines.

3. Quietness

AC motors are relatively quiet in their operation. The simple design and small number of parts in an AC motor translate to a low-volume function, regardless of whether you use the motor for mid-paced or fast operations. The quietness of AC motors makes them preferable for the vast majority of machine operations that take place close to workers and crowds of people.

In restaurants, the low volume of AC motors helps make the environment more relaxing to customers, even as food is prepared just a few feet away. That same quietness is also an essential quality inside the factories and mills where workers are stationed around machines that operate non-stop. The low-volume of the AC motor helps make work conditions bearable factory workers.

4. Flexibility

Another key feature of the AC motor is its flexibility, which allows it to instantly go into motion at the flick of a switch and reverse at the turn of the lever. In machines that are built for both forward and reverse functions, the AC servo motor is the best option for smooth and seamless performance.

The flexibility of AC motors also makes this the ideal motor type for applications that involve a variety of users, such as luxury items and devices that are used by people from all walks of life. In a recliner, for example, an AC motor makes it possible for the user to adjust the sitting position in a variety of angles.

5. Versatility

As one of the most widely used motor types on the market, AC servo motors are available in a vast range of shapes and sizes, from OEM models to customized variations. As such, AC servo motors are available for a wide variety of applications. If you need a solution for a particular component that no longer functions with its original motor, chances are you can find a replacement AC servo motor that will activate the device and restore it to its original level of performance.

6. Constant Speed

AC servo motors are specifically designed to operate at constant speeds. This makes the AC servo motor the preferred option for any operator or manufacturer who needs a motor to run at the same speed throughout an application, regardless of the load. If you run a machine to operate a mild or medium load, the AC motor will run at a constant speed throughout the designated operation.

By contrast, one of the unique features of the DC servo motor is its ability to run at variable speed. DC servo motors are generally passed over by makers of devices that are specifically designed for applications that require constant speed. However, there are select applications in which variable speed is the necessary choice. For devices that fall into this category, DC servo motors are the favored option.

AC servo motors should only be used for their intended purposes. Any attempts to manipulate an AC motor and make it run at variable speeds in the manner of a DC motor could easily cause damage to the motor itself or the device in question. For example, if you try to make an AC motor in a high-velocity device operate at variable speed, it could cause internal heating that could wear on the motor. This, in turn, might force other parts of the device to overcompensate for the motor and spark an overall breakdown.

Whether you have an AC or DC servo motor, it is important to practice preventative maintenance periodically to keep the unit running at peak performance.

In an AC servo motor, the brushes are not contained within the motor itself. Therefore, less action is required to keep the motors maintained and useful. The motor is equipped with a feedback system. The controller or amplifier contains a closed-loop communication system. The control system consists of stator current magnitudes, the phases of which necessitate a control process. With most units, an AC servo motor yields incredibly high revolutions per minute (RPM).

Common AC Servo Motor Applications

AC servo motors are favored in a variety of industries due to their versatility and efficiency. The performance of an AC servo motor is also relatively quiet, which makes the AC motor preferable in various operating environments. Some of the most common machines and appliances to feature AC motors include the following:

  • Water heaters: AC motors offer the control required to administer heat at desired levels. AC motors also offer the efficiency needed to reduce energy usage and fuel consumption.
  • Pumps: The machinery that activates air and water pumps are run on AC motors, which provide the control necessary to regulate supplies of energy in measured movements for uniform discharges through the corresponding pump.
  • Ovens: As with any type of heating device, ovens are required to generate precise temperature levels with speed and efficiency. An AC motor makes it possible for an oven to heat up to a specified temperature within minutes and only use the required amount of energy in the process.
  • Garden equipment: AC motors can provide the speed and precision required for lawn mowers, pruning shears and tillers. They offer the necessary levels of control for cutting grass, weeds and bushes to the desired lengths without excessive electricity or fuel consumption.
  • Off-road vehicles: AC motors are ideal for the types of vehicles that are used to drive across rough and uneven off-road terrain. With an AC motor, the control and efficiency make it possible to activate the necessary driving functions with minimal strain on the engine.

Many of the tools and appliances that everyday people use around the house are powered with AC servo motors. For example, the stovetop and range in your kitchen probably contain an AC motor, as would the dishwasher, microwave oven and laundry machine.

AC Servo Motor Repair From Global Electronic Services

For all the machines and tools in your industrial arsenal, the AC motor is your most valuable component of all. Without the motor, you simply cannot run all those machines or activate the systems that bring your productivity goals to fruition. For this reason, you must ensure that all of your motors are performing optimally at all times.

When you do have motor problems, Global Electronic Services can help you restore your motor to its original condition. Contact us today with any questions you have about AC servo motor repair.

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