Dynamo connected to a motor question
So here's my question, is the rod RPM going to keep increasing non stop or is it going to stop at a certain RPM and not increase any further?


Sorry this is not going to work the way you think it does.

The generator is removing power from the motor and a proportion of that power is converted to electrical energy which you could feed back to the supply, (not as you have shown..) but because of conversion losses, i.e. efficiency, you will always feed back less power than you remove from the motor.

As such, hooking up that arrangement will slow the motor, not accelerate it. It will settle at a slower speed than it would run with the dynamo wire disconnected.