I had an idea to make a homemade bench dynomometer for testing the mechanical power output of motors (both electric and possibly small gas engines) at home. I realised that I have no idea where to start because I don't understand the principle behind it. I understand that hp= torque X RPM. I understand that torque = distance to center X force.
I think of a torque wrench when I think of torque. you put the wrench on a nut and turn the wrench until the needle points to the desired number and then you stall. I could simply measure the torque of motors by stalling them out with a torque wrench and read the number (if I wanted to lose fingers and be bashed repeatedly about the face and head) but that wouldn't give me much useful data because the motor isn't spinning. So how on earth do you measure torque why spinning? I guess I could put a 1' diameter brake disk on the shaft and apply a constant braking force and multiply that constant by the RPM but i'm not sure if I've got the principle right. Is that the right concept (ignoring the fact that the brake would probably lose braking force as it heats up and all other real world variables)?
I think of a torque wrench when I think of torque. you put the wrench on a nut and turn the wrench until the needle points to the desired number and then you stall. I could simply measure the torque of motors by stalling them out with a torque wrench and read the number (if I wanted to lose fingers and be bashed repeatedly about the face and head) but that wouldn't give me much useful data because the motor isn't spinning. So how on earth do you measure torque why spinning? I guess I could put a 1' diameter brake disk on the shaft and apply a constant braking force and multiply that constant by the RPM but i'm not sure if I've got the principle right. Is that the right concept (ignoring the fact that the brake would probably lose braking force as it heats up and all other real world variables)?