AboutDave Nyce Expertise I have been an electronics engineer for 25 years. I can answer questions on analog and digital circuits and my specialty is sensors.
Experience I am the inventor on 23 US patents, and also some foreign ones. Developed sensors for over 25 years. Licensed private pilot (airplane and rotorcraft), have HAM radio license. I'm not an expert in computer networking.
Question The armature of a 220-V dc motor draws 15 A when operating at full load and has a resistance of 2.1 Homes. Determin (a) the counter emf produced by the armature; (b0 the power developed by the armature.
This question is killing me. I am not doing well in this class, I am a civil Eng. student but I have to take this class.
I have the power = 472.5W
I got this from P=I^2 R
Please let me know if I am correct and how I find the emf.
Thanks a ton!!
Mike
Answer 220 volts / 15 amps is 14.6 ohms. You subtract the armature resistance from this, because this does develop motor power, to get 12,567 ohms. Then 15 amps x 12.567 ohms = a back EMF of 188.5 volts.
