Think about it: a plant or distribution center could have six miles or more of conveyor belts. The motors running those belts are sized and designed for maximum load conditions, but those conditions rarely occur. The result? Lots of wasted energy. To take another example, an escalator – which is a type of conveyor belt – is typically designed to carry 250 pounds on every step. How often have you seen 250 pounds of human and/or equipment on every step of an escalator, even in a busy airport?
Even when fully loaded, motors generally operate at about 80 percent efficiency; unloaded, their efficiency plummets. Inefficient motors generate energy waste in the form of heat, vibration and noise. To put it another way, the actual cost of a motor only accounts for about 3% over the lifetime of the equipment…the other 97% is energy!
If you could control that energy consumption, you could significantly reduce maintenance costs and lengthen the life cycle of the motor. That’s where motor efficiency control systems come in. A typical system uses a digital signal processing to monitor the motor, sending data about the load every three seconds or so. This allows the motor to be provided with the optimal amount of power required to perform the mechanical work. Voltage is reduced during lighter loads, cutting energy use without changing the speed of the motor.
- For every ten degrees they reduce the temperature, controls literally double the life of the motor.
- Controls installed on motors with larger voltage (three horsepower and up) and on conveyors with steeper inclines, provide paybacks of less than three years, with energy savings ranging between 22-27%.
- Typically, a strong surge of current rushes into a motor when it’s started up. Over time, this causes wear and tear on the motor, and also incurs high demand charges from the utility provider. The “soft-start” capabilities integrated into most motor controls prevent that from happening.
Pictured above is a Three Phase Motor Efficiency Controller manufactured by Power Efficiency Corporation. This motor control system has a variety of applications, from conveyor belts and escalators to moving walkways and elevators – basically any equipment driven by motors that don’t need to be geared up to 100% capacity 100% of the time.