Bubble Magnus Kalk Stirrer -Stepper Conversion

[oz_robc]

I was warned that this kalk stirrer is loud. But didnt appreciate how LOUD the gearbox is. So I am on a mission to make it whisper quite. I purchased a small 42 stepper motor and a stepper controller to run the stirrer. So testing thus far I cannot hear the stepper motor turning at all. Im sure once its mounted I will get some vibration but right now the motor is silent when held in the hand. So its a good start and looks like it will fit in the housing by drilling a couple of new mounting holes. The only minor thing I have to solve is the shaft on the stepper is slightly smaller than the gearbox, however I will simply create a shim. So its nearly a direct swap as the controller can be set to rotate the stepper when power is applied (12VDC) and the knob sets the speed. Here are some pictures of where its up to.

 

[Townes_Van_Camp]

Very clever. Did that controller have a built in driver?

 

[oz_robc]

Very clever. Did that controller have a built in driver?

Yes, the controller comes in two versions, with and without driver. This one has the driver so stepper directly connects and 12vdc. Only like $25.00. Im getting a second driver for a stepper peristaltic dosing pump to feed the stirrer as well

Search for “SMC02 Stepper Motor Driver and Controller”

 

[Townes_Van_Camp]

Yes, the controller comes in two versions, with and without driver. This one has the driver so stepper directly connects and 12vdc. Only like $25.00. Im getting a second driver for a stepper peristaltic dosing pump to feed the stirrer as well

Search for “SMC02 Stepper Motor Driver and Controller”

I've been looking at driving a peristaltic doser this way also. I'm trying to find a controller with a timer as part of the on-board software.

I just started looking at it. Your post gives me hope.

 

[oz_robc]

New stepper all fitted in place of the geared DC motor.

Was a very easy conversion you do need to:
The stepper motor shaft is 5mm and the stirrer shaft is 6mm so you do need to make a shim
The nylon screws which attach the motor plate to the top of the lid need the knurls taken off.
Had to make some standoffs as the reactor sat a little low in the sump

Im sitting mine in my unused topoff chamber of the Waterbox sump. I dont use it for ATO however will fill it full of RO and thats the reservoir I'll use to push RO into the reactor. So assume every few weeks I can simply fill up that area.

The stepper motor is not completely silent however SOOOO much better than that geared DC motor and the control "RPM" achieved is awesome with the controller. I will play with the micro stepping setting of the controller when I get kalk in there and find the best setting.

 

[Blue Spot Octopus]

Great job, sounds like lots of fun figuring this out. It is nice when a plan comes together.

 

[oz_robc]

Starting with dosing 200ml / day and stirring for 1 minute every 3 hours. I can see the kalk particles drawn upward when the stirrer is running. Have no idea on amount or timing but I suppose the pH trend (profilux) and manual Kh testing will set a baseline I can then change and see the results.

Reef130.4. (100g)