Configuring a High-Power Rack: The Vega Decision, Module by Module

Test system integration · 5 min read · 21 cited facts

The Vega line is one decision repeated: a 3U, 15 kW power module — regenerative load or DC supply — and a bay to put it in. Everything printed about the series follows from that. The 21U, 30U, 35U and 42U chassis sizes, up to 180kW in a single rack, 480 kW across three bays, and up to 6100 amps at up to 1500 VDC are all reached by mixing and matching the same module, not by selecting a fixed model from a table.

That granularity is the specification to interrogate, because it decides two things a headline power number does not: how closely the rack matches the test plan today, and what it can be re-configured into when the programme changes.

The three printed variants

The rack sheet prints three assemblies of the module system — a source-only rack, a bi-directional rack, and a regenerative load rack — each spanning 15kW to 270kW, differing in the direction energy can flow and the voltage window it flows through.

Read the table for its differences rather than its headline. The bi-directional rack tops out at 500V where the source and load racks run to 1500V, and its current ceiling is 6120A against their 8670A. If a test needs both directions of energy flow above 500V, one PSB rack is not the answer — the sheet's own numbers say so, and the honest configuration pairs a source rack with a load rack.

Why module granularity matters more than headline power

A fixed-configuration tester makes you buy its table row. A module system makes you buy your test plan. The difference shows at the edges: the Auto-Ranging output stage delivers full power down to 1/3 of the voltage range, so a module holds its rating across a window rather than at one corner point; the PSI 9000's programmable internal resistance simulates wiring and connector impedance without buying hardware to do it; and the integrated function generator, with an arbitrary mode of up to 100 freely configurable steps, lives in the module itself rather than in an external box that would need its own slot, its own driver and its own calibration.

Regeneration is part of the same decision. Up to 480kW can be loaded or supplied at efficiencies of well over 90%, with the ELR and PSB stages recovering nearly 95% of the loaded energy back to the AC grid. Input is 3-phase at 208 L-L, 400 L-L or 480 L-L — worth settling against the building before the module count is, because the building is the harder thing to change.

The decision walk

• Direction first. DUT only consumes: source rack. DUT only produces: load rack. Energy flows both ways through one port: bi-directional rack — if its window fits.
• Voltage window second. The 1500V racks are the source and load variants; the bi-directional rack spans 60V to 500V. Check the window before the power figure, because power is a module count and voltage is a variant choice.
• Current third. Up to 8670A on the source and load racks, up to 6120A bi-directional — and busbar and cabling decisions follow directly from this line.
• Power last. It is the module count: 15 kW steps, up to 180kW in one rack, 480 kW across three bays.

Where a fixed configuration is the better buy

A configured rack is the right answer when the requirement is genuinely mixed or genuinely unusual. When it is neither, stop. A battery programme that needs charge and discharge with sequencing and reporting is served by a Procyon system — 5 kW to 480 kW, 40 V to 1500 V, with the sequencer and the accuracy figures (DC voltage <0.1%, current <0.2%, power <1%) delivered as one supported product. A single sink requirement under 10.5 kW is one ELR 9000 chassis on a bench, not a bay. Bench-scale work belongs on bench loads — the EL97xx series runs 150 W to 6,000 W with no rack behind it. A customisable rack bought for one fixed duty is paying for a freedom the test plan never exercises.