Duet 2 Wifi Overkill Active Cooling
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why do you need that? what is the real reason?
40-50 mm side fan will do the job, but if the duet board is not under the headbed, you do not need the fan at all... -
A related question, how can I tell if the DWF has sufficient cooling or needs more? Are there 'reasonable' temperatures for the critical components?
(I do have access to an IR camera.)
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I use 2.4A on four different motors without issue using this plate and a small blower fan. I think even this plate might be overkill but at least it's easier to access the board as needed.
https://www.thingiverse.com/thing:3504211
A fan over the top side has a major disadvantage of restricting access to the board in case of needing to adjust any connector or cables.
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@jrdm, very nice design. Did you measure temperatures before and after?
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@zapta Sorry, no I haven't. I did do a few tests to make sure the air flowed consistently but no thermal tests.
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The drivers have active thermal protection. If you are running high current and the steppers stop or miss steps unexpectedly add more cooling.
The passive cooling is good though.
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@doctrucker said in Duet 2 Wifi Overkill Active Cooling:
The drivers have active thermal protection
They also have advanced warning when the silicon reaches ~100C (actual shutdown is about 50C higher at the silicon). I am not sure what the Duet's firmware does with this warning but it is discussed in M305 https://duet3d.dozuki.com/Wiki/Gcode#Section_M305_Set_temperature_sensor_parameters
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@zapta said in Duet 2 Wifi Overkill Active Cooling:
@doctrucker said in Duet 2 Wifi Overkill Active Cooling:
The drivers have active thermal protection
They also have advanced warning when the silicon reaches ~100C (actual shutdown is about 50C higher at the silicon). I am not sure what the Duet's firmware does with this warning but it is discussed in M305 https://duet3d.dozuki.com/Wiki/Gcode#Section_M305_Set_temperature_sensor_parameters
I didn't set that up because it didn't seem like a good way to go.
On his force cancelling printer, Ian Deckingman used spare thermistor channels to read a thermistor potted to a representative driver chip and some motors to watch their temperatures.
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@jrdm That is on the motors, not the stepper drivers. With lower current stepper motors you can overheat the motors long before the stepper drvivers are struggling.
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@doctrucker said in Duet 2 Wifi Overkill Active Cooling:
@jrdm That is on the motors, not the stepper drivers. With lower current stepper motors you can overheat the motors long before the stepper drvivers are struggling.
Wes,
I put a thermistor on one of the driver chips too. That's what I use to control the fan that blows air onto the back of the board. These are set thermostatically to start at 40 Deg C. -
@deckingman I stand corrected!
