A frequency converter (VRF) is a kind of motor controller that powers an electric motor by varying the voltage and frequency supplied to the motor. It is also referred to by other names, such as an inverter, micro-drive, AC drive, frequency converter, programmable drive, and variable speed drive.
Frequency (or hertz) is directly related to engine speed, in revolutions per minute (RPM). This means that the faster the frequency, the faster the RPMs. If a device does not need an electric motor to operate at full speed, a VRF can be used to reduce voltage and frequency to meet the needs of the motor load. As the machine motor speed needs to change, the VRF can increase or decrease the motor speed to meet specific speed requirements.
How it works ?
A frequency converter is the first phase of an AC frequency converter. This frequency converter consists of six diodes which are like the control values used in plumbing systems. They allow the current to travel in one direction. For example, when the voltage of phase A is greater than the voltages of phase B or C, this diode opens and allows current to flow.
When phase B becomes higher than phase A, phase B diode opens and phase A diode closes. This principle also applies to the three diodes on the negative part of the bus. So you get six “pulses” of current as each diode opens and stops. This is a “six-pulse VRF”, and is the standard configuration of frequency converters currently in use.
Uses of VRFs
- Minimize energy consumption and costs
If your application does not need to run at maximum speed, you can reduce energy expenditure by using a VRF to control the motor. The device then allows you to match the speed of the motorized equipment to the required load. No other method of AC electric motor control can achieve this goal.
Electric motor solutions today consume more than 65% of the energy used by industries. By upgrading or installing VRFs to optimize motor control solutions, you can reduce your business’s energy consumption by up to 70%. The other benefit of a VRF is that it can help you reduce production costs and improve product quality. By combining utility discounts and energy efficiency tax incentives, you can get a return on your investment for installing an RVF in just six months.
- Tighten your process control to increase production
You can run your motors at the optimum speed for your application. This will help reduce errors and improve production levels, effectively allowing your business to generate more revenue. On belts and conveyors, you can suppress start-up jerks, resulting in higher efficiency.
- Minimize maintenance and increase equipment life
By controlling your equipment with VRFs that ensure optimum running engine speed, you can reduce maintenance downtime and improve the useful life of your equipment. VRFs help to optimally control the voltage and frequency of the motor and thus can protect the motor from problems such as over voltage, under voltage, phase protection, electrothermal overload, etc.
When using a VRF to start a load, the driven load or motor does not experience the immediate shock of starting on the line. Instead, starting can be smooth, eliminating wear on bearings, gears, and belts. It’s also a smart and sustainable way to reduce or eliminate water hammer, as you can have streamlined acceleration and deceleration cycles.
- Reduce disturbances to power lines
Any voltage drop experienced in the power line can negatively impact voltage sensitive devices such as computers, sensors, and proximity switches. By using VRFs, you can eliminate voltage drops.
- Adjustable operating speed
Unlike conventional engines equipped with a stop-and-go, using VRF allows you to make changes and optimize a process. The device allows starting at reduced speed and allows remote speed adjustment by a process controller or a programmable controller. In industries, improved control can dramatically increase production.
To conclude this article, we recommend that you consult with licensed professionals or recognized experts for appropriate recommendations on the best electrical systems, including frequency converter, for your business needs.