Maddox 3-Phase Indoor Dry-Type Step Down Transformer, 480 Delta V Primary Voltage and 208 Y 120 Secondary Voltage, 15-75kVA Options
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Product Summary
This 3-phase dry-type step-down transformer converts a 480V Delta primary to a 208Y/120V secondary, delivering 208V three-phase power for equipment plus 120V single-phase for receptacles, lighting, and controls from a single unit. The grounded Wye secondary supplies the neutral, and dry-type construction means no oil and no scheduled fluid maintenance.
Specifications:
- Primary voltage: 480V Delta
- Secondary voltage: 208Y/120V (grounded Wye, neutral provided)
- Frequency: 60 Hz
- Temperature rise: 150°C
- Insulation class: 220°C
- Primary taps: 2 above and 4 below nominal, in 2.5% increments
- Windings: aluminum standard (copper available); energy-efficient design
- Enclosure: ventilated dry-type for indoor installation
Note: Wall brackets are not included on every size, so confirm bracket needs at time of order
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Maddox 480V Delta to 208Y/120V 3-Phase Step Down Transformer
This dry-type transformer solves the most common voltage mismatch in commercial and industrial buildings: a facility fed with 480V three-phase service that needs to run 208V equipment and 120V circuits. It takes a 480V Delta primary and produces a 208Y/120V secondary, so one unit delivers 208V three-phase for machinery and 120V single-phase for outlets, lighting, and control circuits. Because the secondary is a grounded Wye, the neutral is available for those single-phase loads without a separately derived source.
Typical Applications
The 480V to 208Y/120V conversion is the workhorse of shops, plants, and commercial fit-outs. Common loads include distribution panels, motors, CNC machines, welders, conveyor systems, pumps, printing equipment, and general fabrication tools. It suits new build-outs as well as adding 208/120V capacity to a facility that already has 480V service on hand.
Dry-Type Construction and Design
Dry-type transformers use air and solid insulation rather than liquid, which removes oil handling, PCB concerns, and fluid maintenance from the equation. This unit carries a 150°C temperature rise with a 220°C insulation class, and the aluminum windings are an energy-efficient design. Primary adjustment taps let an installer fine-tune the output to site conditions, with two taps above nominal and four below, each in 2.5% steps, to compensate for high or low incoming voltage.
Sizing and Electrical Data
Size the transformer to your total connected load in amps, then choose a kVA rating that meets or exceeds that demand with room for growth. The figures below are from the manufacturer source data.
Recommended Accessories
Frequently Asked Questions
It converts 3-phase 480V Delta service into a 208Y/120V secondary. The Wye secondary gives you 208V three-phase for equipment and 120V single-phase for receptacles, lighting, and controls, with a neutral available for the single-phase loads.
Add up the connected load the transformer will feed, in amps, then pick a kVA rating that meets or exceeds that demand with margin for future growth and motor starting. Use the amp columns in the sizing table as a reference, and have an electrician verify against your panel schedule.
Dry-type units use air and solid insulation instead of liquid, so there is no oil to handle, no PCB exposure, and no fluid maintenance. That makes them well suited to indoor and occupied spaces.
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