Schaffner Rewind Service Speeds Transformers Back Into Service

Schaffner has introduced their transformer rewind service which is typically faster and more economical than purchasing a new transformer. Whether performed on-site or in-factory, Schaffner rewinds are often a desirable solution for tight budgets, tight schedules and tight spaces. In-factory refurbishment includes the installation of new coils for the existing transformer plus the associated disassembly and reassembly.  When compared to purchasing a new coil and core, this option routinely yields savings of 30%. If failed transformers removal requires expensive rigging, demolition or other extreme costs, then on-site rewinding may be a viable solution.  Schaffner’s experienced technicians will assess any manufacturer’s dry-type transformer to 35 kV and provide a detailed proposal prior to performing a warranted rebuild. 

When performing on-site rewinds, technicians can also provide a power quality site survey to determine whether additional actions or protections are needed to ensure that the new or rebuilt transformer will meet its intended life cycle.  Harmonics are often the culprit because they cause detrimental effects such as overheating of transformers, power cables, motor and drives.  Harmonics cause higher transformer voltage and insulation stress, resulting in increased heating, reduced life, and higher copper and iron losses due to hysteresis and eddy currents.  Harmonics can also produce higher temperature rise in the electrical network and associated equipment, resulting in losses and shortened service life. 

Schaffner technicians can also recommend and size Active Harmonic Filters, such as ECOsine series, which automatically inject a current to correct the sine wave and mitigate harmonics before they can cause any damage to the electrical system, while maintaining the life span and efficient operation of transformers. Active Filters are available from 50 amps to 400 amps, housed in a NEMA 1 or NEMA 3R enclosure. Higher current ratings, 480vac, 690vac and application engineered systems are available to meet specific user needs.

Harmonics – a silent but deadly Problem

Harmonics are generated by nonlinear components in electrical systems, which distort the sine wave.  Increasing usage of power electronics causes a corresponding increase in voltage distortion, or harmonics.  Common electrical components like motors, pumps, fans, automation equipment, DC fast chargers, equipment with front-end six-pulse rectifiers, and more, all introduce harmonics into the electrical system.  When harmonics are present they can manifest themselves with short-term and long-term consequences.  High harmonic distortion can cause failures or malfunctions of electrical devices.  Schaffner harmonic filters, either ECOsine® Passive or Active, offers complete mitigation, supporting a more reliable power distribution system.