Quote:
Originally Posted by mikels
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Don't make mistake in assuming max fan % is only ~90% - so you should raise to 100%. PWM fan controllers have max output at some level <100% (depending on controller). Raising will NOT increase fan output, but can damage fan controller.
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Dave
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Yes, most of the PWM fans reserve the low end of the scale and the high end of the scale for error criteria or other operating modes so most of the fan motor controllers built into the fans are expecting somewhere in the 10% to 20% as initial on speed and somewhere between 80%-90% duty cycle for maximum fan speed control. Above what ever the maximum expected duty cycle won't result in higher speed.
Not saying people should raise the PWM duty cycle over what ever setting than fan is expecting to see but how would this damage the controller? It wouldn't cause it to operate at higher current. The PWM duty cycle doesn't directly control fan speed - it is a fan speed request signal to the internal BLDC motor controller inside the fan. Also the PWM signal is just a communications level signal - it isn't driving any current into the system itself.
Just wondering.