We aim to be 100% transparent in everything we do as a company, this  includes explaining how our product works.  The following is a list of commonly asked questions, with answers of course.  If you see anything missing from the list below or if you have additional questions please feel free to contact us.  We would be more than happy to answer any of your questions.

What is voltage optimization?

Voltage optimization is an electrical energy conservation technique where voltage is reduced to lower energy consumption.  Often times called Conservation Voltage Regulation or “CVR”, voltage optimization is an energy saving practice that has been used by utilities and large power users for years.  Legend Power’s Harmonizer is designed for commercial and light industrial buildings allowing building owners and operators to fine tune the voltage in their facility to an efficient and optimal level.   The Harmonizer reduces incoming voltage from the grid to reduce energy consumption and greenhouse gas emissions.

How does reducing voltage save energy?

Electrical equipment is designed to operate within a voltage band of -8.33% +5% as per ANSI C84.1 and CSA CAN3-235-83 standards.  Reducing voltage while remaining within the industry standard voltage band will cause equipment to use less energy.  Conversely, higher voltage will cause energy usage to increase and also cause equipment to produce more heat as more power is being consumed.  Not all electrical equipment will respond the same to a voltage reduction, but overall most customers can expect to reduce energy usage by 3-7%.

If I reduce voltage, won’t current (amps) increase and power stay the same?

When a voltage reduction is applied across an entire building consisting of resistive, inductive and fixed output loads, current (amps) will remain unchanged.   Each electrical load will respond differently to a voltage reduction.  As a general rule reducing voltage by 1% will produce the following results:

  • Resistive loads (light bulbs, electric heat):  Current will decrease by 1% and power will be reduced by 2%.
  • Inductive loads (fluorescent lights, some motors):  Current will remain the same and power will be reduced by 1%.
  • Fixed Output loads (VFD motor drives, electronics):  Current will increase by 1% and power will remain constant.

In reality, buildings are complex and the energy savings that Legend Power delivers differs building by building.    This is why Legend Power completes a no-risk building walk through to identify the saving opportunity in our customers’ facilities.

What happens if someone on the same power grid installs a Harmonizer upstream or downstream from my building?

The Harmonizer is installed after the meter in a customer’s building and as such, only affects voltage on the load side of the meter.  The savings potential will not change if another building on the same grid (upstream or downstream) installs a Harmonizer.  The Harmonizer does not have an impact power or voltage on the grid.  If anything, reducing energy consumption through voltage optimization may cause grid voltage to increase (minutely and most likely unnoticeable) as the power grid will be less stressed when less power is used.

Will installing the Harmonizer make my lights dim?

If power is reduced and energy is saved, light output may decrease, but not significantly.   A maximum 3-6% lumen reduction may be noticed with a 6% voltage reduction.   Legend Power does not adjust voltage to out-of-spec levels and as a result, the light output after installation of the Harmonizer-AVR will be within the manufacturer’s design expectations.   A lumen reduction of 3-6% is likely to go unnoticed.   Additionally, light output on many voltage dependent lights already fluctuates by 3-6% throughout the day as grid voltage level are dynamic and fluctuate throughout a typical business day.

Will LED lights save energy with the Harmonizer?

LED lights for the most part will not save energy when voltage is reduced and light output will remain constant as voltage changes.  Some LED’s which are marketed for incandescent spot replacement as “dimmable”, will save energy when voltage is reduced, but as the energy consumption of an LED bulb is very low, the absolute savings are not significant over the course of a billing cycle.

How does voltage optimization effect motors?

Smaller motors (less than 20kW) will often save energy with voltage reduction.  Most small motors in commercial buildings are oversized for the work they need to do.  As a result they operate inefficiently.  Reducing voltage supplied to these motors will save energy, particularly when voltage levels are high.  As the motors are oversized, the potential output loss will not be noticed as they are not heavily loaded.

Larger unregulated motors (over 20kW) may also save energy with a voltage reduction, but not as much as smaller motors.  Most large motors are sized correctly for the work being performed and are often regulated by a VFD. Reducing voltage to a VFD will not save energy and the savings delivered to a large motor correctly sized will be minimal (0-2%).  A motor under heavy load will pull additional current (amps) as voltage levels decrease to ensure it can perform the work required. Our audit includes a review of larger motors and other critical loads to ensure voltage and current remain within nameplate rating and ensure that efficient operation is achieved.

How do you measure and verify the achieved savings?

We have designed an M&V program into Harmonizer’s functionality to measure achieved savings in real time.  After installing the Harmonizer, the system is set to an M&V mode where the unit goes from full voltage reduction (usually 6%), to bypass(0%).  The cycle takes 30 minutes to complete – 15 minutes at full voltage reduction and 15 minutes at bypass.  The Harmonizer cycles back and forth over the course of one week while a power quality analyzer measures the power usage at reduced and bypassed voltage levels.  The comparison of energy used at reduced vs. bypassed voltages determines the achieved savings.

I have Power Factor Correction capacitors installed in my building, will the Harmonizer still help me save energy?

Yes, you will still save energy.  Power factor correction devices do not impact the savings the Harmonizer will deliver in your building.  The Harmonizer reduces voltage and saves energy, it is not correcting an existing power quality problem such as low power factor.  Power factor correction is designed to eliminate or reduce apparent power (low power factor) and does not have a noticeable impact on voltage levels.  Many utilities charge a penalty if power factor is below 90% and  it may be financially beneficial to take corrective measure if power factor is below the 90%.  Although Power factor correction and the Harmonizer are both installed in an electrical room, the technologies are not related.

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