Variable Frequency Drive (VFD) can be used in lots of fields. Variable frequency drives are widely used to control the speed of AC motors, like conveyor systems, blower speeds, pump speeds, machine tool speeds, & other applications that require variable speed with variable torque. In some applications such as speed control for a conveyor, the variable frequency drive is installed with a remote potentiometer that personnel can adjust manually to set the speed for the conveyor. In this type of application, the personnel who use the conveyor can manually set the motor speed with the minimum & maximum frequency that is programmed into the variable frequency drive parameters.

Variable speed drives control duplex pumps

Advantages:

1. Reduction in maintenance costs. Variable speed drives are inherently soft start, increasing motor and linkage life.

2. Pumps can be alternated more frequently, say every 24 hours, increasing the life of the equipment.

3. On pump failure, the standby pump is automatically started with alarm indication.

4. Start-Stop and reset of pumps can be done by the variable speed drives.

5. Optional manual selector switch overrides the automatic pump alternation sequence.

6. In applications, where increased flow is required , on a temporary basis, the lead or primary pump may remain at maximum flow with the second “back up” pump enabled and varied to meet the system demand.

Variable frequency drive on Booster Pumps

Pressure booster pumps essentially add pressure to a commercial building’s water supply at times when the water mains pressure is not sufficient. Most multistory apartment complexes, hotels, etc, require pressure booster pumps to supply adequate pressure to terminal units such as showers and bathrooms.

VFD can be added to pressure booster pumps as an alternative to using pressure control valves. This saves the energy and eliminates its cost and maintenance. The vfd savings can amount to 20% or more, simply due to the safety factor used during the design of the system. If the suction pressure of the pump varies, the over-sizing of the pump required to handle the lowest suction pressure does not penalize the installation, when the suction pressure increases.

Variable frequency drive in pharmaceutical industry

Electric motors in pharmaceutical industry consumes significant amounts of electricity; estimated to be about two-thirds of all usage. Even a simple air conditioning system, costing a few hundred pounds, can be expected to consume many tens of thousands of pounds worth of electricity over its useful lifetime. Variable frequency drives can help to make significant energy savings by controlling the motor speed.

Creating closer links between these two areas of a business is an important objective. Tools like online variable frequency drive payback calculators will go some way towards achieving this; however, by themselves they won't produce a result – there also has to be real buy-in from the business itself.

VFD for Compressor in oil and gas industry

The benefits of using VFDs are:

1. Reduced downtime because gas turbines require frequent maintenance while VFDs and motors require very little maintenance. This enables more production, lower maintenance expense, and improved productivity.

2. Accurate speed control and process control allowing the most optimum plant flow balance to be obtained.

3. Lower energy costs because the VFD and motor has a higher efficiency than most gas turbines, especially at part load.

4. Zero CO2 and NOX emissions at the operating station and greatly reduced noise. This feature often makes electric prime movers the only selection in applications near urban regions or regions with existing air quality problems.

5. Independent of ambient temperature. Gas turbines generate less power when the inlet air temperature rises since the air density is reduced and less oxygen reaches the combustion chambers. VFDs and motors are not affected by temperature.

6. Lower capital equipment, spare parts and maintenance cost.

VFD selection for refrigeration compressor

Choose a variable frequency drive (VFD) for refrigeration compressor control must be conducted with great care, as a variable frequency drive selected too small-sized may present some disadvantages. These can be avoided by using the VFD selection software. Based on a process of individual selection and qualifying of the variable frequency drive suited for a given refrigeration compressor, safe and energy-saving operation of the refrigeration compressor can be achieved.