Why power supply Power Factor is key to LED signage module performance
BY I.M. Lyteman
The Power Factor in your LED power supply is one of the keys to premium LED performance.
Power Factor indicates how well an LED driver uses electricity. Simply put, a power supply with a higher Power Factor is more efficient and wastes less energy. A high Power Factor is essential for your operating system’s efficiency. It translates to improved grid performance, lower utility bills and extended LED lifespan that meet standards mandated by programs like Energy Star.
What is Power Factor?
Power Factor is the ratio of real power (measured in Watts) to apparent power (in volt-amps). This number ranges from 0.0-1.0. The ideal Power Factor, when current and voltage are perfectly in sync, is 1.0. Cheaper power supplies often have lower Power Factors (from 0.50 to 0.70).
Why does it matter?
High Power Factor reduces wasted energy, lowering power consumption and the costs that go with it. A lower Power Factor draws more current to produce the same amount of light, adding stress to the power grid and often resulting in financial penalties for low-Power Factor consumers. Modern LED drivers often feature active Power Factor correction that reduces stress on the power supply itself. This prevents overheating, improves system reliability and lengthens LED lifespans.
How is it done?
Passive Power Factor correction uses simple inductors and capacitors that are cheaper but less effective. Active Power Factor correction features electronic circuits that shape the input current to match the voltage waveform. This results in very high Power Factors that are close to the “ideal” of 1.0.
Real costs
Most electric utility companies actually slap surcharges on larger customers who draw electricity from the grid with poor Power Factor performance. Those surcharges can range from 2% to a staggering 80% for end users operating at 0.50 Power Factor. So “saving” a few dollars up front on a cheap, low-quality power supply will cost the end user a small fortune in energy bills over the life of the install. For example, a midsize restaurant with a good Power Factor that uses 40,000 kWh a year at 12.76 cents/kWh would have a bill of $5,104. With a poor Power Factor of 0.50 and the accompanying surcharge, that bill would reach $9,187 a year.
Key things to know
When you choose a power supply for your LED signage projects, look for active Power Factor correction with a Power Factor of at least 0.90. Every AgiLight-branded power supply features a Power Factor of at least ≥ 0.90, and the range tops out as high as 0.98. This ensures efficiency for your sign, reduces costs for your customers and protects the lifespan of signage modules.
