750 KVA, 24-Pulse Phase-Shifted Oil-Filled Transformer

Specifications:

• 24-Pulse Transformer, 750 KVA, 3 PH, 60 Hz, P/N 10290L1
• Primary: 480 VAC L-L, Delta
• Secondary: Four isolated 480 VAC, 3 PH extended Delta phase-shifted outputs
• Nominal Phase Shifts: -22.5°, -7.5°, +7.5°, +22.5°
• Copper Windings
• ONAN Cooling
• Temperature Rise: 65 °C
• Non-PCB Mineral Oil
• NEMA 4X Stainless Steel Enclosure, 316L
• Total Dimensions: 96” W x 72” D x 86” H
• Total Weight: 9,000 lbs.

A photo of the complete transformer is shown below:

1. Specifications

Preliminary Electrical Performance

2. Construction Details

Core
• Three-leg grain-oriented silicon-steel core, low-loss step-lap/mitered construction.
• Conservative flux-density design for harmonic VSD duty and reduced excitation/noise.
• Core grounded at one controlled point; clamps arranged to minimize circulating currents.

Windings
• Copper primary winding, 480 V Delta.
• Four separate 480 V extended-delta secondary winding systems, each feeding one identical 6-diode bridge.
• Secondary voltage, winding resistance and leakage impedance to be closely matched to promote equal bridge loading.
• Oil-compatible cellulose/pressboard winding insulation and barriers.
• Electrostatic shielding between primary and secondary systems is recommended for VSD/ESP service.

Tank, Cooling and Offshore Protection
• Welded carbon-steel oil tank with carbon-steel ONAN radiator banks.
• Special offshore coating system: abrasive blast preparation, zinc-rich primer, high-build epoxy intermediate coat and
marine/offshore topcoat or customer-approved equivalent.
• NEMA 4X stainless-steel terminal/control enclosure; 316L preferred.
• ONAN radiator system sized with thermal margin for harmonic and stray losses.

Reservoir / Conservator
• Separate external reservoir is not required.
• Recommended construction is a sealed-tank design with adequate internal expansion/head space for mineral-oil volume
change.
• Provide pressure/vacuum gauge and pressure-relief device.

Preliminary Losses, Thermal Performance, Size and Weight

To discuss your specific application, please call our number at (714) 624-4740, or send us an email at quote@lcmagnetics.com.