Regenerative drives convert braking energy into free electricity

ABB’s new ACS800-11 variable speed regenerative drives capture braking energy from electric motors. They return it in to the network as free electricity, significantly improving energy efficiency.

In industry, electric motors are often used in applications with frequent brake applications. A braking chopper and external electrical resistors dissipate braking energy as heat. Resistor braking often needs forced cooling, requiring the use of additional energy.

ACS800-11 however, can recover the braking energy of a load and return it to the power system. This offers significant energy savings compared with resistor breaking. They create less heat, reduce power consumption, and simplify the installation. Typical applications include all types of cranes, unwinders, hoisting applications and discontinuous centrifuges and downhill conveyors

As an example, consider a waste handling crane with a 55 kW hoisting motor, a 9 kW long travel motor and a 4.5 kW trolley motor. Using a regenerative drive annual savings total approx. 15.6 megawatt hours (MWh) – or 2,300 euros. This reduction by 32 percent corresponds to the annual energy consumption of four typical households.

 

Reducing engineering costs

Since there is no need for external brake components, ABB’s regenerative drives are significantly more compact than conventional solutions. Markedly, they reduce space requirement by up to 85 percent due to their compact design. Lower heat dissipation due to regenerative braking reduces the need for air conditioning of control room. Furthermore, lower engineering and material costs and a smaller footprint deliver more savings.

 

Clean energy from regenerative drives

Recovered energy is “clean” and has a high quality. It can is usable by other loads increasing plant efficiency. The drives control Cos φ of the fundamental to unity under all load conditions. This mean the reactive power, further optimising energy consumption.

Typically, non-linear electrical loads, also including variable speed drives, cause harmonics leading to unwanted voltage and current distortions in the networks. These harmonics result in unreliable operation and can heat other loads. This requires additional cooling, causes energy loss and in the worst case premature failure.

The ABB drives prevent harmful harmonics before they appear. ACS880 can control cosine phi of the fundamental to unity under all load conditions. Optimising reactive power and fully meets harmonics standards such as IEEE519, IEC61000-3-12 and G5/4.

The drives can also feed track parameters like motor speed, torque, motor currents, various temperatures and many other.

 

Wall-mounted regenerative drives, ACS880-11

Power ratings: 2.2 to 110 kW

Enclosure classes: IP20 for cabinet mounting, IP21 (as standard) for wall-mounting and IP55 for dusty and wet environments

 

 

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