Industrial power conversion is about matching the incoming voltage to what your equipment actually needs. With two 30kVA three-phase autotransformers on the table, the decision is not which one is generally better; it's which direction your power has to move. One unit steps 480V down to 400V. The other steps 208V up to 480V. Getting this direction wrong could leave your machinery running on the wrong voltage.
Quick Verdict
Choose the 30kVA Step Down Transformer 480V to 400V if your supply is 480V and your load is built for 400V. Choose the 30kVA Step Up Transformer 208V to 480V if your supply is 208V and your load needs 480V. The step-down is listed at USD 900.00, and the step-up is listed at USD 950.00, so the price spread is about $50. That spread is secondary to the voltage match.
At a Glance
| Product | Listed Price | Conversion | Primary to Secondary |
|---|---|---|---|
| 30kVA Step Down Transformer 480V to 400V | USD 900.00 | Step-down | 480V to 400V |
| 30kVA Step Up Transformer 208V to 480V | USD 950.00 | Step-up | 208V to 480V |
Where Each Product Wins
- The step-down is the right tool when your incoming three-phase line is 480V and your equipment expects 400V. It handles the exact voltage drop those machines need.
- The step-up is the right tool when the facility provides 208V three-phase and your equipment requires 480V. It is the only one of the two that performs that voltage lift.
Common Ground
Both units are 3-phase to 3-phase autotransformers operating at 60Hz AC-to-AC. The physical package is the same: 20.5 inches by 17 inches by 21.5 inches, with a gross weight near 100kg. Both include built-in ventilation to help with heat dissipation during continuous operation.
Product Notes
30kVA Step Down Transformer 480V to 400V Industrial Power Converter - NEW
This converter is for a specific scenario: 480V three-phase going in, 400V three-phase coming out. That makes it a direct match for equipment wired for 400V when the supply is 480V. Its conversion function is step-down, so you cannot reverse the flow and turn a 208V source into 480V. Before wiring it in, account for the load limits: maximum resistive load is 24 kVA and maximum inductive load is 18 kVA. Even with the 30kVA headline rating, those ceilings are what you should use when sizing your load. If your input and output voltages line up with this unit, it is the direct match among the two.
30kVA Step Up Transformer 208V to 480V Industrial Power Converter 3 Phase
This converter is the one to select when your incoming service is 208V three-phase but your equipment needs 480V. It steps the voltage up, making it the only product in this pair that can bridge that gap. Its step-up function means you should not use it for a 480V-to-400V application. The same load restrictions apply here: keep resistive loads at or below 24 kVA and inductive loads at or below 18 kVA. The transformer is rated at 30kVA, which describes the maximum possible output before those derating factors kick in. If your machine expects 400V and your line is 480V, this unit is the wrong direction; the step-down transformer is the one you need.
Final Choice by Use Case
For a 480V supply feeding 400V equipment, the 30kVA Step Down Transformer 480V to 400V is the decision. For a 208V supply feeding 480V equipment, the 30kVA Step Up Transformer 208V to 480V is the decision. Match the direction of conversion to your input and output voltages, and the correct product becomes obvious.
