Variable speed AC drives are crucial in food and beverage manufacturing to improve energy efficiency, but that's just the beginning. For example, predictive downtime capabilities built into an AC drive reduce process downtime potential. This benefit can help avoid missed deadlines and product spoilage, while increasing cost savings.
Thus, in order to reap the full rewards AC drives offer, it is vital for food and beverage processors to understand their total value. That includes:
Reduced maintenance costs: Variable frequency drives reduce the need for mechanical or hydraulic gearboxes and clutches.
Reduced downtime: AC drives can be used to monitor load changes to predict mechanical wear, like worn bearings, and may avoid extended downtime.
Reduced equipment cost: Because AC drives are connected directly to driven loads, they can be less expensive than DC drive or mechanical drive systems.
Distributed control: AC drives that possess programmable logic control functionality reduce the need for external controls. Local controls allow operation when control equipment is not required or not operating properly.
Reduced wiring and installation time: AC drives with serial communication capabilities can be controlled and monitored by communication networks over a single set or pair of cables.
Reduced personnel costs: AC drives may be used to reduce the number of personnel required for many processes, allowing for better workforce allocation.
Incentives and rebates: Utilities often offer cash rebates and other incentives for implementation of energy efficiency measures. State and federal tax incentives can be leveraged as well.
Simplification: As AC drive technology continues to improve performance, it is possible to deploy them for jobs that used to require much more complex DC motor drives, servo systems, wye-delta or reversing starters and wound-rotor motors.
Peak shaving or curtailment: In addition to energy use charges (kWh), utilities also charge for peak demand (kW). Curtailment incentives are sometimes offered to reduce electrical demand during heavy-use periods. AC drives can be used to avoid these peaks by operating at reduced speed.
The energy savings potential of AC drives shouldn't be overlooked, as they are especially significant in variable torque applications, like mixing, pumping, washing, compressed air control and indoor air quality. In these applications, a small speed change results in very large changes in energy consumption. Put simply, the more time a system runs at less than full speed, the more energy is saved.
For non-variable torque applications, energy savings from speed control commonly take a backseat to the performance improvements. In other words, the ability to control speed and torque allows customers to improve quality, reduce waste and increase production output.
As with any piece of automation and control equipment, proper installation and commissioning are critical to achieve the maximum benefits of a variable frequency AC drive. To get started, the best rule of thumb is to make contact with a trusted OEM panel builder, system integrator or solutions supplier, armed with specifics about a given food or beverage processing application so the maximum benefits can be accrued.
