So hopefully I can get some advice from someone who knows better here. I want to control my 90vdc motor via my aduino uno and use the wall as a power source. I will be using a bridge rectifier in a similar fashion to this video: http://www.youtube.com/watch?v=LtXtmVV1kjY Although instead of a dimmer switch, I will be using an arduino Uno. I just don’t know how or where on the board to connect the alligator clip/wires! Or if this is the correct way to do this.
I just don't know how or where on the board to connect the alligator clip/wires!
You don't connect them anywhere. If it's a serious question then it implies that your understanding of electric circuits is not good enough to deal with high voltage and high power motors safely. At these voltages, there is a significant danger of killing or seriously injuring somebody and this is not a sensible starter project.
Fortunately it wasn't powered up at that point, but exposed cables and croc clips strewn over the table seems like an accident waiting to happen. 50V is enough to kill, and 90/110V can kill easily. The thought of trying to attach croc clips carrying that sort of voltage to an Arduino is downright scary.