A Bench Built for Capacitors
Applying a capacitor correctly is as important as choosing the right part. To support customers more effectively, BeiLuo has opened an FAE verification bench dedicated to Faratronic film capacitors. The bench lets our engineers measure ripple current, equivalent series resistance, snubber clamping behaviour and motor run performance before a customer commits to a design, turning advice into evidence rather than opinion. A capacitor is the component that decides the life of many converters and motors, so measuring it directly is one of the most useful things a distributor can do for a customer.
What We Measure
The bench is equipped with high-bandwidth oscilloscopes, differential probes, current sensors, an LCR meter and a thermal stage. Engineers characterise the DC link by measuring the ripple current and the resulting case temperature, they evaluate a snubber by measuring the clamp voltage at the module terminals, and they check a motor capacitor by measuring capacitance stability over temperature. Measuring at the actual operating point matters, because a capacitor that looks comfortable on a datasheet can still run hot in a real converter.
Ripple Current and Temperature
Ripple-current measurement begins with the current waveform at the capacitor. The engineers measure the RMS value at the switching frequency, multiply by the ESR to estimate the internal loss, and confirm the case temperature with a thermal probe. From those measurements they recommend a value and a case style that keep the hot-spot temperature within rating at the customer ambient. Because a film capacitor has a low ESR, the recommendation is usually a smaller part than an electrolytic would require.
From Selection to Validation
When a customer asks which capacitor suits their circuit, our FAE team can now validate the recommendation on the bench. We compare a PCB DC-Link capacitor against an aluminum-case part, size a snubber from the measured loop energy, and check that a motor capacitor holds its value over the temperature range. The result is a design path backed by measured data, which reduces the risk of late-stage surprises and shortens the path from concept to production.
Snubber Validation
Snubber validation is where the bench earns its keep. The engineers measure the turn-off spike at the module terminals with and without the snubber, and confirm that the capacitance and the voltage class clamp the spike within a safe margin. For high-voltage converters, this validation is especially valuable, because a marginal snubber setting can destroy an expensive module in a single event. By measuring the clamp directly, the sequence is confirmed rather than assumed.
Thermal Validation
Thermal design is often where converters fail. The bench measures case temperature under load, letting us verify the capacitor thermal design against the ambient and the expected ripple current. For a DC link that runs near its limit, this validation is especially valuable, because a marginal thermal path can derate a design severely or shorten its life. The measurement also confirms that the low-ESR film part contributes little heat, so the switching devices dominate as intended.
Supporting Customers Remotely
Not every customer can send hardware, so the bench also produces reference data that our team shares directly: recommended capacitance and case style, expected ripple current, snubber capacitance and clamp levels for common circuit combinations. This shortens customer bring-up and lets design teams start from a known-good baseline, then fine-tune on their own bench. Over time, this reference data becomes a library that shortens the path for every new customer in the same power class.
A Lab That Answers Questions
The purpose of the bench is not to look impressive but to answer the questions customers actually ask: which capacitor, which case, how much ripple current, and how much overshoot should I expect. A lab that answers those questions with measurement is what turns a component distributor into an engineering partner, and it is the standard BeiLuo intends to hold for Faratronic customers through 2026.
Bring-Up Support in Practice
In practice, the bench shortens bring-up in a predictable way. A customer sends the circuit, the bus voltage and the ripple-current spectrum; the engineers propose a capacitor and case style, estimate the hot-spot temperature and return measured evidence. The customer then reproduces the result on their own hardware, starting from a known-good baseline rather than a blank page. For teams without a dedicated power-electronics lab, that support is often the difference between a design that ships on schedule and one that stalls in validation.