Electronic cooling
Electronic power equipment generate heat and shall be appropriately cooled, because failures may burn equipment and start a fire.
Natural cooling is to be preferred because it avoid the risk associated with fan failure, but is not always possible.
It is preferable to have electronics installed in a naturally ventilated area, vertically to create a natural convection airflow. Enclosing them properly may help good airflow guiding.
Component datasheet requirement shall be respected, meaning that if for the most penalising case, there is a requirement for a radiator, it shall be installed. Low cost equipment may not always comply with datasheet, so better cooling than theorically required place you on the safe side.
Components which need a careful review against their heating are :
- Voltage regulators
- FET
- DC/DC SSR
Stepper driver generally incorporate temperature safety, but they may need good cooling. Dissipated power rise as the square of the current, so increasing size/power of an equipment shall be done with caution. Basic power generated by continuous current on FET can be evaluated as W = Rds(on)*I² PWM control increase the generated heat. Example : for a heat bed of 200W supplied in 12V, I = 16.66A. If resistance of the driving FET -Rds(on)- is 0.047 Ohm, power is 13W, and the FET shall heatsinked and well cooled to not burn. Another board using a FET with 0.0032 Ohm will dissipate only 0.89W, and may not need heatsink at low frequency PWM. If a SSR is used, the power is 'Voltage drop'*Current, so with a voltage drop of 1.5V , for chosen example the power will be 25W, needing serious heat-sinking and also significantly reducing the heatbed available power.
box
A fire proof box is desirable for safety, and if well designed it could be a good airflow guide for electronic board. See how power supplies are built.
