Question 10Electricity & Electronics - Assistant Engineer

The correct answer is D. The welding of contacts in an AC winch hoist controller can be caused by low applied voltage to the operating coil (less than 85% of rated voltage) or by weak springs. Low voltage can cause excessive current flow through the contacts, leading to overheating and welding. Weak springs may not provide enough force to separate the contacts, allowing them to weld together. The other options are incorrect because: A) Excessively strong springs would not cause welding of the contacts. B) Excessively high voltage (more than 110% of rated voltage) can also cause welding, but this is not the only potential cause. C) Weak springs, not strong springs, can contribute to contact welding.