I have an Arduino project which uses a L298N to control a 12V DC brush motor (with an apparent 1.8A stall current rating). The motor is equipped with an encoder but I don't think that is relevant to my problem.
While prototyping I have been using an ATX PSU for a PC which I modified for a 'bench supply', which provides 5v, 9v and 12v with ample current.
With this PSU, everything is great - no problems, motor is smooth. I thought any old 12V power supply that could provide at least 2A would be sufficient as a replacement.
However, every other power supply I have tried does not perform nearly as well as my ATX PSU; the motor feels weaker but most importantly it sounds like it's having a bad time. It's hard to explain, but the motor makes a whole lot of mechanical noise, especially when under load. I don't mean a PwM whine, but more a noise like it has bad bearings or gearbox or something. The motor jitters/judders/vibrates as it moves instead of giving nice linear feedback/movement.
As it works fine with my ATX PSU, I can only assume this is a power supply issue. Also I think I can rule out lack of current based on the specs of the ones I have tried:
I tried this first: EFISH Power Transformer 12V 2A 24W,AC 100-240V to DC 12V Power Supply Adapter https://www.amazon.co.uk/gp/product/B07KZB5TQX
Then this, as I thought the first one might just be a cheap unit that wasn't as capable as it said: BW High Quality 12V 5A 60W DC Power Supply https://www.amazon.co.uk/gp/product/B00C676JNM/
Finally, I tried this, thinking a more 'dedicated' regulated switched mode power supply would do it: Velain 12V 5A DC Universal Regulated Switching Power Supply Converter, 60W Adapter Transformer https://www.amazon.co.uk/gp/product/B01N0Y5E8K/
Motor specs: Gear Motor 12V-DC 12V Encoder Gear Motor Speed Reduction Pure Copper Coil Motor (500RPM) https://www.amazon.co.uk/gp/product/B07XRDVXRZ/ Rated speed (RPM): 500 Reduction Ratio 9.6 No Load
- Speed ±10%RPM 620
- Current A 0.07 Rated
- Speed ±10%RPM 500
- Current A 0.3 Torque KG.CM 0.2 Stall
- Torque KG.CM 0.9
- Current A 1.8 Rated Voltage 12V
Any help much appreciated.