Variable frequency drives use a technique referred to as pulse-width modulation (PWM) to provide voltage of varying frequency to an AC induction motor. The inverter, or output, stage of the VFD uses insulated gate bipolar transistors (IGBTs) that switch on-and-off rapidly, creating trapezoidal pulses of varying width to simulate AC sinusoidal voltage. But the windings in […]
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AC drives for motor and motion control
Today’s VFDs perform far more than just traditional motor controls. Some include computing, I/O handling, and even motion-control capabilities. Such intelligent drives excel in smaller and localized systems. Case in point from material handling: Some VFDs with onboard PLCs work for motion control on infeed conveyors. In one specific case, a photoeye and tower light […]
Video: Yaskawa GA800 ac drive for industrial applications
In a recent Design World video with my super-smooth colleague Mike Santora, I got the chance to play with a GA800 ac drive demo from Yaskawa America Inc. This VFD includes network communications, embedded functional safety, and easy-to-use tools (including a smartphone app) for configuration and remote access. Yaskawa sent us a sample of the […]
Video: New general-purpose ac drives from Control Techniques Commander series
Control Techniques a Nidec Motor Corporation business now offers its latest Commander series general-purpose ac drives. Detailing the new Commander C200 and C300 is this video: The Commander C series is available in frame sizes 1 through 9 with horsepower ratings from 0.33 to 200 hp and supply voltages of 115, 230, and 460 Vac. […]
How do STO inputs affect SIL3/PLe conformity for AC drives?
Safe Torque Off, or STO, is a drive-based safety function that stops the drive from providing power to the motor, without interrupting power to the drive. Activating the STO function produces an uncontrolled stop, meaning the motor coasts to a stop based on the system’s inertia and friction. The STO function also prevents an unexpected […]
What are low voltage AC drives and why should you use them?
Despite the benefits of using medium voltage AC drives for high horsepower motors, low voltage technology holds a dominant place in the AC drive market, for both low- and high-power applications. There are multiple reasons for this, not the least of which are cost and availability. Medium voltage drives have historically been custom-engineered solutions, with low-volume production, […]
FAQ: What are medium voltage AC drives, and where are they used?
Recall that the basic equation for electric power is P = VI, or, power = voltage multiplied by current. This means that for a given power level, voltage and current are inversely proportional. In other words, the higher the supply voltage, the lower the current draw will be. For AC motors that are used in high-power applications, […]
FAQ: How does EU Regulation 428/2009 apply to AC drives?
AC drives capable of operating at frequencies of 600 Hz or greater are generally referred to as “high-frequency” drives. These drives are considered by the U.S. and the EU to be dual-use devices, meaning that although they are commonly used in civilian applications, such as industrial equipment, they can also be used in military applications or […]
FAQ: What is V/Hz control mode for AC drives?
AC motors are commonly paired with variable frequency drives (VFDs), which control motor speed by regulating the frequency of the supplied voltage. Depending on the application and level of speed regulation required, VFDs can be controlled by either scalar or vector methods. The most common type of VFD control is a scalar method referred to as volts […]
KB Electronics case study: Custom ac drive for new boat lift
Now, a new custom ac drive is helping make a boat lift work faster and survive longer. A boat lift for residential use essentially takes a boat up in hoists and then stores it out of the water. That helps keep the boat — usually a private watercraft stored adjacent to a lake, river, or canal populated […]
