Variable frequency drives are a must need item for your AC motor-driven application if you want to reduce the energy costs. The VFDs as they are known help to adjust the speed of the motor based on the requirement of the process thus eliminating the necessity of running the motor at full speeds.

Variable Torque Usage Leads to Lesser Energy Consumption

Greater energy savings are obtained in case of variable torque usage when compared with applications involving constant torque. As per the Affinity Laws, the torque is directly proportional to square of speed while horsepower is directly proportional to roughly cube of speed. Therefore, even if speed decreases by very small amounts the reduction in horsepower required is huge and this is responsible for offering large energy savings. In HVAC systems, the motor-driven application is not needed to run at full speeds and so variable frequency drives lead to lesser consumption of energy.

Variable Speed Drives for Better Process Control

All variable speed drive dealers will confirm that usage of VFDs indeed ensure firmer process control. Your motor can be run only at the maximum speed with the help of full voltage starters while reduced voltage soft starters or soft starts can hike the motor speed to the fullest and back again to shutoff only in a gradual manner. VFDs are programmable to ensure the running of your motor at a specific, accurate speed, to shutoff at a specific, accurate speed and employ a specific quantity of torque. These drives offer open-loop operation as well as closed-loop operation.

Increased Life of Equipment and Lesser Maintenance

The motor is ramped up to its operating speed steadily with the help of variable speed drives whereas single-speed starting systems involve abrupt start of the motor endangering it to a high starting torque and current increases which is many times the maximum load current. VFD dealers emphasize this advantage as it leads to lesser electrical and mechanical stress and reduced repair and maintenance expenditures. The motor life and that of the equipment driven by it are enhanced.

Though reduced voltage soft starters and soft starts too, ramp up the motor steadily it is only the variable speed drives that can be programmed to hike the motor in a much more smooth and steady manner.

Disadvantages of Full Voltage Starters

The power system is burdened with undesirable voltage sag when full voltage starters are used and this affects the other loads negatively. The chances of causing extreme wear and tear of the motor in addition to causing shock damage also cannot be ruled out. Restrictions are placed on the motor size that can be used under the full voltage starting system.

Summarizing

Variable frequency drives are being used in a large number of applications largely due to the many benefits afforded by them. However, in harsh conditions it is unwise to install your VFD exposed. At such times you need to remember to enclose it in a VFD control panel. VFD dealers and the related Automatic Electrical Control Panel manufacturers will elaborate the importance of such enclosures that protect your equipment in totality.