Why High Power Factor?
Ferro-magnetic neon transformers have a very low power factor. This means the apparent power factor measured by the volt-amperes is greater that the power in actual watts consumed. So a neon transformer designated as Normal Power Factor (NPF) is approximately 50 percent power factor during regular operation.
Some areas of the country mandate a power factor of 90 percent or greater. Transformer manufacturers typically offer High Power Factor (HPF) to be used in these installations. A capacitor inserted in the transformer enclosure connected to the primary raises the power factor from 50 to 95 percent. The requirement for a High Power Factor neon transformer is due to the fact that the higher the power factor, the lower the line current (primary amps) for the given wattage of the transformer.
The increase of primary current causes a loss of power in the utility supply circuit, for which the customer does not pay since the meter registers only the watts consumed. The line loss is absorbed by the utility as a cost of doing business, which ultimately results in a rate increase. Therefore, in the interest of conservation and keeping rates as low as possible, High Power Factor neon transformers may be specified and/or required.
Wattage consumption is based solely on secondary voltage and current (milliamps). It does not change whether the primary input voltage is 120V or 277V, nor does it change if the transformers are normal or high power factor. The higher the power factor, the closer the wattage approaches the volt-amperes (VA).
Upfront cost savings can be realized by using High Power Factor transformers or 277V primary input. Line amperage is effectively reduced by half, thus cutting the number of circuits required by that same percent. For example, a 15,000V, 30mA transformer at 120V is approximately 4.0 amps, but in 277V, it is 1.8 amps, and in HPF, it is 2.10 amps. The reduced load amps allows more transformers per circuit, thus less circuits overall.
Transco, Inc.
1059 Colite Drive
West Columbia, SC 29170
Ph: 800-869-6366 Fax: 803-794-8528
