AC drives are part of a technology which enables the drive to control speeds on electrical motors, and are often used in systems such as HVAC units. The AC drive is able to covert energy from electricity into mechanical energy by using electromagnetic induction. Motors which use AC drives have fixed speeds which are determined by how frequently they receive power. They also operate on fixed torque, or a twisting motion which can cause the drive to rotate. Even though the speed is fixed in an AC drive, it can be adjusted to different speeds depending on its application or the purpose of the motor being used.

With a DC drive, field current (field windings) or armature (rotating windings) voltage is used to control speed of the motor, both of which supply precise control. The speed of the drive is proportional to the armature voltage, although it is inversely proportional to field current or motor flux. This type of drive is used in elevators, conveyors, material handling, and many other applications in a variety of industries. Since the armature is made by current conductors which terminate at the commutator, DC voltage is then applied to the armature via carbon brushes which are on the commutator.

When generating AC power there needs to be DC supplied to the field winding on the rotor. To do this, a brushless exciter is mounted on the rotor and generates AC on its windings. The AC is then taken to rotating rectifiers, now in the form of DC, to the generator’s armature. When doing this, it’s typically to keep the output voltage of the generator as near as possible to a constant, regardless of the variations of the load. To determine the amount of DC which flows to the main rotor, it’s regulated by altering the DC which is supplied to the field winding on the stator.

Motor protection controls are typically used in both the processing and manufacturing industries. They are used to control, protect, measure and supervise asynchronous motors. They are typically used with contractor controlled HV motors or circuit breakers as well as medium sized and larger LV motors in varying degrees of drives. Not only do they protect motor functions, but they protect voltage and power and energy measurements as well. Remote or localized control of a start and stop function is also facilitated. Motor protection controls can come in different configurations, although there are generally four standard ones.

Power controllers are used to select transmitter power output within a system to obtain the highest maximum performance possible. Depending on the system they are being used with they can optimize different metrics, anything from network capacity to link data rate to life of a network and its devices. In some instances, algorithms are used for things such as wireless LANs or sensor networks. One benefit of using a power controller is that it can transmit at a higher power, which can mean a higher signal for the receiver. Another benefit can be a reduced bit error rate on the link for digital communication.

Soft starts are used to reduce both torque and load for the powertrain on AC electric motors. They can also help to reign in the surge of currency while the motor is starting up. By doing this, it reduces excess stress on both the motor and corresponding shaft and other components such as power cables. When soft starts are used, they help to extend the life of the motor they are used on. Soft starts can be made of either electrical or mechanical devices or some type of combination of the two. Mechanical soft starts limit the torque while electrical soft starts reduce the current input.

Solid state brakes work by electronically stopping a load. They work by injecting a specified DC current amount into an AC motor which has three phases. The automatic braking controller can be adjusted to the needs of stopping a load fast, time and time again, even during situations when the conditions of any given load may change due to a variety of factors. Solid state brakes can increase productivity, enhance safety, and provide maintenance free operation on a variety of motors. Solid state brakes come in different sizes based on amperage and the application they will be used for.

Solid state starters come in a variety of sizes, depending on the application. They are used with AC motors to reduce torque and load within a powertrain. When they reduce the load they reduce any mechanical stress to the motor or shaft and any connecting power cables. They also reduce the surge of the current as the motor starts. By using a solid state starter, it’s possible to extend the life of any system on which it’s being used. Much like soft starts, they can be made using either electrical or mechanical systems, depending on the application.