Enersavers™ Controller
Escalator - Honolulu International Airport

Delivering energy savings for a 15hp Three-Phase motor
The Enersavers™ Controller allowed an average energy savings of up to 28% for an average annual savings of $921.42
with Utility rebates.

The Opportunity :

Honolulu International Airport was a great candidate for the Enersavers™ Controller to be used on their 80+ escalators to reduce energy consumption as well as provide soft starting to extend the life of the AC Induction motor. The airport management agreed to install two controllers on a randomly selected pair of escalators (one up and one down) for testing and evaluation.

The objective to the initial test was to measure the kWh consumption of the escalators over a two week period and establish the difference in power consumption between the motor run off of a standard AC motor starter (bypass) and when controlled by the Enersavers™ Controller. The escalators chosen had approximately a twenty foot rise/descent. The escalators chosen were subject to various loading conditions based upon the number of passengers traveling at a given time.

The Challenge :

An AC Induction motor converts electrical energy to mechanical energy. The design of an AC Induction motor performs this "conversion" at its most efficient point when the motor is approximately 80% loaded. At any other point, the motor efficiency falls. Until now, this rapid drop in motor efficiency has been the cause of waste in the form of kilowatts, heat, and early motor failure. The Enersavers™ Controller is the only solid state motor controller that has bridged the gap. Excessive heat is a major cause of motor failure and indicative of other motor problems. Heat destroys motor insulation resulting in windings shorting, and the motor is no longer functional. Excessive loading, improper cooling, voltage imbalance, phase loss and surge voltages are some of the main causes of motor heating.

Escalators represent ideal candidates for the Enersavers™ Controller technology due to their motors being sized to handle the maximum number of passengers yet most frequently operating in an under loaded or unloaded condition. Escalator motors must be designed to drive the full load of the escalator regardless of the actual amount of load (people and materials). This design requirement causes the AC motor to fall from its most efficient operating load point to an under loaded condition, which results in motor losses.

The Solution :

Enersavers™ Controller was used to reduce energy consumption by sensing the drop in mechanical loading (efficiency) and adjusts the energy to an AC Induction motor to the precise level required to perform the mechanical work. In doing so, high amounts of wasted energy that was dissipated in the form of motor losses,are eliminated.

A survey of both the up and the down escalator motors determined:

1. The escalators were rarely loaded to their designed capacityThe load on the motors was variableThe motors were started across-the-line
2. Both escalators ran 24 hours per day, 7 days per week, 52 weeks per year for a total of 8,760 hours per year.

The Enersavers™ Controllers were installed and ran for six days (140 hours) being controlled and six days in bypass. The results were collected in 15 minute intervals by the local utility.

Down Escalator Test Results - 27% Energy Savings
Testing Period: January 28, 1999 - February 11, 1999

Up Escalator Test Results - 29% Energy Savings
Testing Period: April 20, 1999 - May 4, 1999

For more Information

To find out more about Enersavers™ products and solutions, call us at +65 6325 1028.