Voltage Controller Saves Energy, Prolongs Life of Motors
- Created: Tuesday, 01 January 2008
In the late 1970s, Frank Nola, an engineer at NASA’s Marshall Space Flight Center, had an idea for reducing energy waste in small induction motors. The idea, a method to electronically adjust the voltage in accordance with the motor’s load, was patented in 1984. The voltage controllers have become known as Nola devices, and they are still as useful today as they were more than 20 years ago, as they can be applied anywhere an AC induction motor is being used at a constant speed but with a variable load. These have the ability to save operators a great deal of energy when the motor is lightly loaded, which translates into savings in cost and resources.
The soft start functionality gradually introduces power to the motor, thus eliminating the harsh, violent mechanical stresses of having the device go from a dormant state to one of full activity. This prevents it from running too hot and increases the motor’s lifetime.
According to the company, electric motors consume about a quarter of all electricity used in the country. Power Efficiency’s energy-saving soft start employs electric circuits to monitor power use and motor workload, matching the amount of power to the workload.
The device can sense if the motor is lightly loaded or idling, which is when the motor is least efficient, and then ramps the power usage down while maintaining the motor at a constant speed. This feature can reduce power consumption by up to 40 percent when the motor is lightly loaded. This is a great advantage for any motor that routinely runs under variable loads.
Escalators and elevators with motor-generator (MG) sets are prime examples of the types of machinery that benefit from energy savings the device provides. Take, for example, an escalator: Sometimes it is full of people; sometimes it may have a single passenger; and other times it may be empty. The motor inside the escalator must be large enough to handle the maximum possible load—a full escalator—but that rarely happens. When the escalator has few passengers, the motor driving it is lightly loaded and wasting energy. This waste of energy is addressed by the Power Efficiency energy-saving soft start, as it senses the load and instructs the motor to use just the right amount of energy (usually much less) for the job.
The product can pay for itself through the reduction in electricity. According to Power Efficiency, the product often pays for itself within 3 years, depending on the duty cycle of the motor and the prevailing power rates. In many instances, the purchaser is eligible for utility rebates for the environmental protection it provides.