K-Factor Transformers0 pages

Ventilated Distribution Transformers

K-Factor transformers are designed to reduce the heating effects of harmonic currents created by loads like those shown in Chart A. The K-Factor rating is an index of the transformer's ability to withstand harmonic content while operating within the temperature limits of its insulating system. SolaHD K-Factor transformers have UL ratings of K-4, K-13, and K-20.

The SolaHD K-Factor design is a specialized transformer that offers these benefits:

• Conductors capable of carrying the harmonic currents of non-linear loads without exceeding the temperature rating of the insulation system.

• A transformer design that takes into account the increase in naturally occurring "stray" losses caused by non-linear loads. These losses cause standard transformers to dramatically overheat and substantially shorten design life.

• A core and coil design that manages the DC flux caused by triplen harmonics. As these harmonics increase, they cause additional current to circulate in the delta winding. This produces a DC flux in the core which leads to core saturation, voltage instability and overheating.

Features

• Conductors to carry harmonics of a K-rated load without exceeding insulation temperature ratings

• UL 1561 listed up to K-20 rated protection

• Rated temperature rise of 150°C, 220°C insulation

• Shielded for quality power

• Basic design takes "stray losses" into account and functions within safe operating temperatures

• Core and coil design engineered to manage the zero sequence flux caused by triplen harmonics

• Provides 100% rated current without overheating the windings or saturating the core

E25872

Accessories and Optional Design Styles*

• Wall mounting brackets (500 lbs maximum) (Item WB1C)

• Weather Shields (UL-3R)

• Totally enclosed non-ventilated designs (TENV) (Non UL)

• Low temperature rise units available

• Open core and coil designs (UL Recognized)

• Copper Wound designs

• Alternate voltages

• Compliant to NEMA TP-1 Standards

* Not all optional designs are UL listed. Contact Technical Services.

Chart A: Typical Load K-Factors

Electric discharge lighting..............................................................K-4

UPS with optional input filter..........................................................K-4

Welders.........................................................................................K-4

Induction heating equipment.........................................................K-4

PLCs and solid state controls........................................................K-4

Telecommunications equipment (e.g.. PBX).................................K-13

UPS without input filtering............................................................K-13

Multiwire receptacle circuits in general care areas of

health care facilities and classrooms of schools, etc....................K-13

Multi-wire receptacle circuits supplying inspection or

testing equipment on an assembly or production line...................K-13

Mainframe computer loads..........................................................K-20

Solid state motor drives (variable speed drives)............................K-20

REPRINTED WITH PERMISSION FROM EDI MAGAZINE

Visit our website at www.solaheviduty.com or contact Technical Services at (800) 377-4384 with any questions.