January 9, 2025
Description
Magnetic Stirrer.
I wanted a magnetic stirrer for the workshop for stirring various finishes and paints, some quite thick and difficult to stir. I opted for a RS380 DC motor and a speed controller that I could slow the motor down to a low RPM and still have the torque required. I used 4 x 12mm x 5mm, N52 magnets (2x stacked north up and 2x stacked south up) in the magnetic rotor to transfer the motor toque to the stir bar. The rotor can accommodate upto 13mm magnets, a small dab of E6000 glue will secure them in place. The rotor and spinner has a small hole in the centre for the motor spindle which will need drilling out just a little for a snug fit push fit onto the motor spindle. There is a small indent on the top of the rotor to take a dab of glue if required. The motor can be height adjusted and clamped into place by using a cable tie in the recess provided on the mount. Position the top of the rotor as close as possible to the underside of the perspex lid without it rubbing. A PTFE stir bar of 35mm x 8mm is my preferred size (even in small jam jars). A 240v illuminated switch and an integrated 240v to 12v transformer to complete the box. I have included a full parts list from Ali Express and a simple wiring diagram for the project. Fix the motor mount first, close to the centre of the box through the bolt holes provided and arrange the transformer board and speed controller around it , mount the switch and potentiometer on the front.
Cut the Transformer pcb board as small as possible, just big enough for the transformer and the screw terminals. On the pcb boards 240v side there are 1 x 2gang terminal for live and the same for neutral so the safety capacitor has it’s own terminals. Connect and hot glue the board into place.
Connect the 2 amp speed controller with separate potentiometer and hot glue into place.
A box of 120mm x 120mm x 80mm is a good size. No lid is supplied as I used clear perspex of 3mm thick, under neath that a piece of 6mm ply wood with a 75mm hole cut in the middle resting on the corner lugs of the box creating a very solid top.
I have included a “spinner disc” which aesthetically sits on the motor spindle before the magnetic rotor, it has a spiral pattern on it. Change the filament to a different colour on the last two layers to take advantage
NOTE.. IF USING A METAL BOX APPROPRIATE EARTHING WILL BE REQUIRED.
Magnetic Stirrer Components.
RS-380 Motor.. https://vi.aliexpress.com/item/1005005897479939.html?spm=a2g0o.order_list.order_list_main.5.21ef1802DO3XeT&gatewayAdapt=glo2vnm
Speed controller.. (2 amp separate pot) https://vi.aliexpress.com/item/1005006592430892.html?spm=a2g0o.order_list.order_list_main.11.21ef1802DO3XeT&gatewayAdapt=glo2vnm
Safety Capacitor (0.1UF 15mm) https://vi.aliexpress.com/item/1005002538662756.html?spm=a2g0o.order_list.order_list_main.77.21ef1802DO3XeT&gatewayAdapt=glo2vnm
12v Transformer.. (10Watts) https://vi.aliexpress.com/item/1005006010491821.html?spm=a2g0o.order_list.order_list_main.486.21ef1802DO3XeT&gatewayAdapt=glo2vnm
Prototype Board https://vi.aliexpress.com/item/1005005061801122.html?spm=a2g0o.order_list.order_list_main.505.21ef1802DO3XeT&gatewayAdapt=glo2vnm
Magnets..(12x 5mm) https://vi.aliexpress.com/item/1005005426580014.html?spm=a2g0o.order_list.order_list_main.41.21ef1802DO3XeT&gatewayAdapt=glo2vnm
License:
Creative Commons - Attribution - Share Alike
Higi-Styx
