Types of DC Machines
Homo polar machines: These types of machines are used where low voltage and high currents are required e.g., Faraday’s disc dynamo
Hetero polar machines: The DC machines that are commonly used fall under this category.
The type of generator used in welding is homo polar machine. Differential compound generator also belongs to homo polar machines. The generator is so designed that it delivers a voltage high enough to start the arc and reduce the voltage as required to maintain the arc during the welding.
Unlike AC, DC flows continuously in one direction from a negative charge to positive charge. Although DC flows only one way, you can manipulate it to flow in the appropriate direction, which is its polarity.
DC welding is preferred when using high welding speeds and when welding is out – of – position.