Emerson Offers SolaHD K-Rated Transformers to Address Power Harmonics

Power harmonics have become an increasingly important issue in today’s 
industrial environment, a result of the growing number of sensitive 
electronics, high-powered computers and sophisticated production 
technology employed on many factory floors, production facilities and 
labs. <br><br>Harmonics are, essentially, current and voltage with frequencies that are not aligned — also known as non-linear loads. SolaHD

James R. Dukart

Power harmonics have become an increasingly important issue in today’s industrial environment, a result of the growing number of sensitive electronics, high-powered computers and sophisticated production technology employed on many factory floors, production facilities and labs.

Harmonics are, essentially, current and voltage with frequencies that are not aligned — also known as non-linear loads. They serve no useful purpose, but can be harmful to facilities and equipment, resulting in power losses and lowered efficiency. Harmonics return over the neutral and are dissipated as heat in cables and load devices.

Without the right transformers that can handle harmonics, companies may find that they are forced to “de-rate” transformers or are simply not getting the full useful life from both their transformers and other electrical equipment.

For example, operating a transformer at 10 degrees C above its insulation-rated class will cause about a 50% reduction in the life of the transformer. If the overheating temperature is high enough or long enough, the transformer will prematurely fail.  Other warning signs of harmonics include overheated neutral conductors and panels, unexplained tripping of circuit breakers, line voltage distortion, equipment failure, electrical fires, control equipment mis-operation, and inter-ference on communication lines.

Emerson’s SolaHD “K-Rated” transformers are designed to address power harmonics. K-Rated transformers can serve varying degrees of nonlinear load without exceeding rated temperature rise limits. Each K-Rated transformer, moreover is assigned a “K-Factor” that tells engineers just what amount of non-linear load the transformer can handle. The higher the K-Factor, the more non-linear loads can be handled.

Emerson SolaHD K-Rated Transformers’ basic design takes into account increases in naturally occurring stray losses caused by non-linear loads that can cause standard transformers to dra-matically overheat and fail prematurely. The core and coil design manages the DC flux caused by triplen harmonics.

K-Rated transformers are preferred over oversized (derated) conventional transformers because they are designed to supply nonlinear loads, are equipped with 200% rated neutral bus, and are likely to be smaller and less expensive.

Disadvantages of an over-sized standard transformer may include the requirement for a higher short-circuit rating on circuit breakers and the drawing of a higher inrush current. Derating a standard transformer is a temporary fix that often translates into lower efficiency operation.


Photo courtesy of SolaHD