I broke a column fan, so I have an 81x500mm cross-flow fan I want to turn in to a "smart" fan. It has an 8mm collar on it so I know I need a motor with an 8mm shaft. From looking at column fans, they run up to about 1800RPM. The old motor says "CK-50c class 155" on it. Other than it being 50W, I can't find anything else about it. My assumption is that the smarts of this project are going to be managed by something running ESPhome.
So to my actual question...how do I select a motor and controller for this job which can be controlled with esphome?
esphome has support for a few options for motor control. H-bridge seems like an obvious choice. It all depends on what you mean by "smart". What capabilities do you want to enable and what control do you need over the motor? Is on/off enough or do you need speed control (how much/many)?
Mounting: custom enclosure. Fan has a 6mm shaft at the non-motor end, so 6mm pillow block. Motor will be mounted however it can.
Control: speed is the main thing. Ideally I would like a rotary encoder connected to the ESP so that I can adjust the speed locally as well but that's not a deal-breaker.
You need to find a motor that has the diameter, length, and shape necessary to fit your existing fan.
If you get a simple multi-speed motor, control is probably much easier.
Normally people use variable speed as part of an automatic control system to control some process/temperature and want to apply a variable amount of it to get better control.
I think you are possibly over complicating the project and that will raise the cost.
Sure. I wouldn't be trying to do it with ESPhome and Home Assistant if I wanted it to be easy! I am not just trying to scratch an itch here, it's also something to learn and have fun with.
Normally people use variable speed as part of an automatic control system to control some process/temperature and want to apply a variable amount of it to get better control.
What are you really trying to do with this fan?
It's mainly going to live under my desk, replacing a gang of noisy PC case fans connected to a PWM "knob". I want fine control over the speed partly to adjust the speed to just below background noise level. The fan my partner bought to replace the one I broke has 20 speeds.
It will also help me with the next project I have which is to fix a cooker hood which has a 3-speed AC motor. The low and medium speeds have broken so now only runs at 100%. You might have guessed by now that I am not just going to replace the motor, I am going to build a new control system as well
Be aware there is some technology there, since the conditions are harsh (heat and grease).
Making things that move air quiet is also hard.
Many companies don't go to much trouble because many people associate more noise as being more powerful/better.
Why? What is your goal?
I think control systems are great since I first learned many details about them many decades ago. I have found that simple control systems often are just as good at meeting the requirements. Understanding the requirements is the first step before a good design. It is best not to skip that step.
Without specs of your motor, no-one can tell you what you should use.
Be aware that controller for type x dc motor has nothing to do with controller for type y ac motor.
