There are very simple rules guiding on the wire size:
- A higher section area (bigger wire) will have less resistance per unit of length
- The lesser the resistance, the lesser the losses
- The lesser losses, the lesser the temperature increase
Based on your wire material, a higher temperature can be tolerated. However, for a general consumer electronic device such as a 3D printer, you don’t want to keep your wires too hot. Considering heat and convection cooling from the wires can get complicated quickly.
As a general rule of thumb, a value ranging from 1% up to 3% can be used as the losses in a wire.
Taking our previous example, our 48W heater could use a cable with a loss ranging from 0.48W up to 1.44W.
Considering a loss of 0.48W (1%) over 1 meter of wire, the sizes shown in the table below should be used.
Hi, I’m planning to do a conversion of a a printer that uses 12V mainboard and components to use a 24V Ender 3 mainboard. The original stepper motors are 24byj48 12V. Is it safe to drive them directly with the current coming from the 24V Ender 3 mainboard or do I run the risk of burning them out? Talking about the XYZ steppers, the extruder stepper will be replaced with a NEMA17 from the Ender 3. Will a DC-DC buck converter on each stepper work?
The motors drivers chop the current, so the input voltage has no effect on the motor.
Make sure however that the mainboard can handle 24V. Some motherboards can’t. A quick check is to validate the capacitors around the stepper drivers are at least rated at 35V.
Thanx! This is a fantastic article.
Jan. (The Netherlands)
Hi, I’m having a hard time finding an answer to my question and am hoping that you can help. I have a 24v system running a SKR E3 mini 1.2 main board I am trying to use a 12v 220w 410x410mm hotbed with this setup. I was thinking of using a second power supply 12v. Do I need a MOSFET and OPTO isolator with this setup and will I need to tie the grounds of the 12v and 24v supplies?
Hi Hunter. I’m not an expert, but I can give you some hints! If you are using an optocoupler, you don’t need to tie the grounds. Personally, I would tie the grounds, it’s safer like this as there won’t be any voltage between the two PSU (less risk of shock). A new power mosfet would be required.
Want to make sure is the Ender 5 pro a 24v system or a 12v
Hi Ronnie. I’m not an expert in these printers. The best way to find this info in through the manufacturer website.