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Heat issue with G2 18V25 that didn't exist with original 18V25

I have migrated our production to the SMC G2 18V25 controller from the original 18V25 controller. From previous discussions with Pololu engineers on the phone I redesigned the mount to have vents and passive cooling. In testing in the lab before production it was noticed that there were heat issues (50+ deg. C) with the G2 driver. However none failed during this time. The first batch were shipped and promptly overheated in the customer’s control panel (19-21 deg. C ambient). The driver runs at 17-18 Amps for 20-30 minutes by which time it heats to 65 deg. C per the SMC G2 software. At this point the driver drops to 2-3 amps and the equipment fails production testing. The current production run included the last of the original 18V25 controllers. In the same exact use conditions the “G1” runs at 17-18 amps and 35-40 deg. C (those machines shipped). What do I do with these G2 controllers that have not failed (2 in soldering and at least 1 in production/use)…how can I deal with the heat build-up and still keep the packaging reasonable? Heat sink costs killed off another product line.


I am surprised that the G2 units are getting that much hotter in the same setup, and also that it would fail at 65°C. Were the G2 units that failed damaged permanently? What are you using for a power supply, and what is your load? Could you post pictures of the SMCs in the system (both G1 and G2 if possible)? Could you also post a copy of the settings file from the G2 units? They can be saved with the "Save settings file option in the “File” drop-down menu in the control center.