Reflected waves, also known as transmission line effects or standing waves, are over-voltages that can damage the motor and cable. The use of IGBTs (insulated gate bipolar transistors) in variable frequency drives has helped to improve VFD performance in several ways. First, their quick switching time (also referred to as rise time, or dV/dt) means […]
Drives + Supplies
FAQ: What is a VFD line reactor?
Many of the components that make up a variable frequency drive (VFD) are semiconductor components, which are sensitive to power or current surges, voltage spikes, line distortion, and general power anomalies. A line reactor is an optional component that can be added to a drive system to protect the VFD and other devices from power […]
What is a rectifier?
AC motors can be operated directly from AC supply voltage, but this is only suitable if the motor is required to run at constant speed. If the speed or load requirements of the motor change, an AC drive — also referred to as a variable frequency drive (VFD) — can vary the voltage and frequency […]
FAQ: What is stepper drive idle-current reduction and why does it help?
When stepper motors operate, they operate by drawing current continuously. This method of operation ensures more accurate positioning and more consistent torque. However, this also means an increase of energy they use and the amount of heat they produce. This holds true even when the stepper motor is idling. Idling is not a very efficient […]
FAQ: How do drives for switched-reluctance motors work?
Switched-reluctance motors are stepmotors that accept power to their stators (instead of their rotors) to use output mechanical force through the use of reluctance. This is magnetomotive force to magnetic flux. Switched-reluctance motors use drives that differ from those that pair with other stepper motors. That’s because switched-reluctance motors have nonlinear magnetic behavior … but output high […]
FAQ: What is dynamic braking and when is it used?
When a motor is in an overhauling condition—that is, the load is moving faster than the designated motor speed—the motor acts as a generator and produces electrical energy from mechanical energy. This electrical energy, however, needs somewhere to go, and the most common way of dealing with its release is through dynamic braking. How dynamic […]
Lenze i500 Frequency Inverter Series Features Enhanced WLAN Diagnostics Module
Lenze has launched an enhanced version of its i500 frequency inverter series, equipped with a WLAN diagnostic module for easy parameter setting when commissioning and diagnosing motor inverters for a range of machine applications, including pumps and fans, conveyors, formers, winders, traveling drives, tool and hoist drives. Lenze is a global leader and manufacturer of […]
New VFDs offer quick, easy setup
The new ACF Series from American Control Electronics is an open chassis microprocessor-based variable frequency drive (VFD) that offers the simplicity of a DC drive. ACF700 drives are designed for quick and easy setup without any programming, in contrast to the complex programming associated with standard VFDs. The drives are equipped with user-adjustable trim pots […]
Nidec introduces Answer Drives
With the introduction of new AD 1000 and AD 700E variable frequency drives, Nidec Motor Corporation is expanding its new ACCU- Series family of variable speed products that offer product compatibility for a true system solution. The AD1000 is a high-performance variable frequency drive that can reduce energy consumption by automatically adjusting to changing […]
FAQ: When are closed-loop and open-loop vector control useful?
AC drives have historically been controlled by a scalar method known as volts per hertz (V/Hz), in which the drive maintains a constant voltage-to-frequency ratio in order to maintain stable torque production. However, the V/Hz control scheme doesn’t allow tight speed regulation and is limited in its ability to produce torque at low speeds. Vector […]