Two Machines, One Shaft — the Grid Pays Only the Losses.
An EV's range is not one single number; it's the integral of the powertrain's efficiency over every operating point a drive cycle visits. That map of efficiency — islands across the speed-torque plane — is the actual product Neometrix's e-motor test bench manufactures, and everything else in the system exists to make that map genuinely true. It's a four-quadrant, back-to-back test architecture to the 350 kW class and EV-grade speeds, with a precision torque flange, full battery emulation for the inverter, chamber pairing for temperature, and production end-of-line testers for the factory floor.
Back-to-Back Is the Honest Architecture
The motor under test drives; a load machine absorbs — and critically, both sit on a single shared DC bus, so the absorbed power circulates straight back to the driving side rather than being wasted as heat. The grid only ever supplies the losses. A 350 kW test that would otherwise demand 350 kW of continuous supply and 350 kW of heat rejection instead draws only tens of kilowatts. That isn't a convenience feature — it's what makes full-power, long-duration endurance testing financially and thermally viable at all.
Torque Is Measured, Not Inferred
A precision flange in the shaft line — repeatability in the ±0.03% class per DIN 1319, temperature-compensated, IP54-rated — reads mechanical power directly, while power analysers separately read the electrical side. Divide one by the other and the efficiency map appears. Get the flange measurement wrong, even slightly, and every single island on that map shifts, silently corrupting every efficiency number the bench produces.
The Inverter Is Half the Powertrain
A battery emulator, covering the 0–1,000 V class, stands in for the actual battery pack — with realistic source impedance included, not just a clean voltage source — so the motor, inverter and control software can all be proven together as a system. A separate motor emulator variant proves inverters and controllers with no rotating hardware at all, which is invaluable for early-stage development and safe fault testing.
Sized to the Machines and the Duty
Power class, speed, inertia, emulation depth and chamber pairing all follow from the specific machines being tested — from individual hub motors up to complete e-axles — and the standards they need to answer to. The reference envelope described here was engineered against India's current EV-laboratory build-out, including a live national-lab requirement pairing a 350 kW bench with a gearbox and climatic chamber. No order followed this specific configuration, so no delivered bench is claimed on this page.
Development Bench and End-of-Line Testers, One Creed
The same measurement discipline scales from the R&D development bench right down to the factory floor: no-load and load testing, back-EMF and Hall-sensor verification, stator surge comparison, hipot and insulation-resistance testing, torque-constant and phase-resistance checks — production gates that catch a bad winding in seconds on the line, rather than months later in a warranty claim.
Chamber, Dyno, EMC — the Family Closes
This bench pairs directly with Neometrix's climatic chambers for temperature testing, stands beside the chassis dynamometer for full-vehicle-level testing, and gets its inverters verified in the EMI/EMC laboratory — the whole EV test family engineered as one coherent line rather than isolated point products.
Frequently Asked Questions
Why does a "back-to-back" test architecture matter for testing high-power electric motors?
Because it solves a real practical problem: testing a 350 kW motor at full power would otherwise require the electrical grid to supply 350 kW continuously, and the test facility to reject that entire 350 kW as waste heat -- which is expensive, thermally demanding, and makes long-duration endurance testing impractical. In a back-to-back architecture, the motor under test and a load machine share a common DC bus, so the power the load machine absorbs circulates electrically back to drive the test motor, rather than being dissipated as heat. The grid then only needs to supply the difference -- the actual electrical and mechanical losses in the system -- which for a well-designed test setup is typically only tens of kilowatts even when testing at the full 350 kW power level.
Why is a battery emulator used instead of just testing an EV inverter with a real battery pack?
A real battery pack introduces variables that make repeatable, controlled testing difficult -- its voltage sags under load in ways that depend on its state of charge and age, its internal impedance isn't easily adjustable, and using a real pack for extended durability or fault testing risks damaging an expensive component. A battery emulator, covering a wide voltage range (0-1,000V class) with programmable source impedance and realistic sag behaviour, lets engineers test the inverter and motor control software against conditions that accurately represent a real battery pack -- including its imperfections -- without the cost, safety risk or variability of using an actual pack for every test.
Get In Touch
For full specifications, RFQs, or a technical discussion about the e-motor test bench:
- Product page: E-Motor Test Bench
- Email: contact@neometrixgroup.com
- Phone: +91-7777-876-876
Top comments (0)