A variable frequency drive (VFD) is a type of motor controller that drives an electric motor by varying the frequency and voltage of its power supply. The VFD also has the capacity to control ramp-up and ramp-down of the motor during start or stop, respectively. Even though the drive controls the frequency and voltage of power supplied to the motor, we often refer to this as speed control, since the result is an adjustment of motor speed.

In addition, today’s drives integrate networking and diagnostic capabilities to better control performance and increase productivity. So, energy savings, intelligent motor control and reduction of peak-current drawn are three great reasons to choose a VFD as the controller in every motor-driven system.

The most common uses of a VFD are for control of fans, pumps and compressors, and these applications account for 75% of all drives operating globally. Soft starters and across-the-line contactors are other, less sophisticated types of motor controllers. A soft starter is a solid-state device and provides a gentle ramp-up to full speed during startup of an electric motor.

An across-the-line contactor is a type of motor controller that applies the full line voltage to an electric motor.

Delta's VFD-EL-W series is the new generation compact vector control drive. Simple, delicate and durable design inherits Delta’s superior drive technology.

- Various essential functions are built-in as standard, including: Multi-step Operation; Torque Compensation; PID Control; Multi-Pump Control; Water Supply at Constant Pressure; Leakage Detection function and so on.

- It also with complete built-in protection mechanism, such as: Over-current; Over-voltage; Low-voltage; Over-heat; Over-load; Over-torque; Phase Loss Protection and so on.

VFD-EL-W not only saves the extra cost but also increase the market competitiveness with the best technics.

This series adopts FOC (Field Oriented Control) which is a far more precise vector control algorithm. It can be used in both speed control and position control similar to a servo motor drive. The multi-function I/O terminal is expanded to meet users' various application needs. In addition, it is supplied with a Windows based PC software program for managing parameters and dynamic monitoring. It provides an excellent solution for load regulation. It can output 150% of rated torque at zero speed, and it can have "point to point" and relative distance control functions for position control, making it the best choice for challenging industrial control applications.

Sensorless Open and Closed Loop Vector AC Drive. The VFD-B series represents Delta's NEMA1 general purpose AC drive. The VFD-B series drive is rated to provide constant torque, featuring open and closed loop vector control. Delta offers an optional 2000 Hz high speed output that can be factory programmed at the customer's request.

The VFD-C2000 series is a high-level field oriented control AC motor drive with a high-performance variable-frequency technology, FOC control. It features versatile driving controls, modular design, wide variety of applications, easy maintenance, low malfunction rate, self diagnosis and competitive market price and brings customers not only the high-efficiency construction but also the most economic solution to compete with the global market.

The VFD-C2000 series is a high-level field oriented control AC motor drive with a high-performance variable-frequency technology, FOC control. It features versatile driving controls, modular design, wide variety of applications, easy maintenance, low malfunction rate, self diagnosis and competitive market price and brings customers not only the high-efficiency construction but also the most economic solution to compete with the global market.