Finding drive power limits

Lately I have been concentrating on finding the current & power limits of the Argon drive. I have used the artificial load unit as test load.

Testing has gone well and has revealed things I didn’t know about Argon. The most positive surprise is that the drive seems to be able to deliver a lot more continuous power than calculated. The first anticipated limiting factor in the design was the equivalent series resistance (ESR) of the bulk capacitors. ESR sets the limit to the maximum ripple current that AC-to-DC power supply can handle because current flowing through capacitor’s internal resistance will heat them up and eventually make them reach their maximum safe temperature.

By calculating maximum ripple current & power based on capacitor specs I came up with figure of 700W continuous power before capacitors get too hot (105⁰C). However, by testing I found out that even at 1200W continuous output the caps didn’t get warmer than 37⁰C. I think capacitors either are way better than specified or their ESR is specified at 105⁰C which may be much higher than the ESR in room temperature. So 700W is probably the limit when capacitors already run hot (needs very high ambient temperature) and at least 1.2kW may be extracted at room temperature.

Power resistor fused open as terminals desoldered them selves

Oops! Artificial load unit power resistor wire terminals desoldered them selves under little bit too much pressure

9 thoughts on “Finding drive power limits

  1. The drive should have active cooling (a vent maybe). Maybe there is enough space for it?
    This drive should be able (I hope so) to be suitable for at least 2kW motors. After all this is will be the most powerful drive offered by Granite.

    • Enclosure is full of vent holes, so no problem there. Also drive has current sharing wire terminals so several drives can share their power supplies for higher power when other drives are under lighter load. The power stage should be able to handle 2 kW+ output. So yes, its the most powerful GD drive yet!

        • “When it’s ready” :)

          Seriously speaking I don’t like being in dept of any kind so sales begin once we have items to ship! First production run is very near.

    • We plan soon to produce small batch of final design drives for early users & testers before going into full production. There will be news about it!

  2. hello
    I live in France and I followed the ARGON project since I discovered granite device.
    We have a project retrofit of machine tools industry is ongoing and pending drivers, I’d be betat-testers for the project ARGON on this machine tools, it will represent minimum 3 driver that work together by machine.


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