Question 180Electricity & Electronics - 1st Asst/Chief

The correct answer is B) stop contacts have become welded together. If the contacts of a motor starter or controller fail to drop out when the 'stop' button is depressed, it is most likely due to the stop contacts becoming welded together. This can happen when high current flows through the contacts, causing them to fuse or weld together, preventing them from opening when the stop button is pressed. The other options are incorrect because: A) the stop contacts would likely be carrying sufficient current to open properly; C) and D) the shading coil issues would not prevent the stop contacts from opening.