Abstract: An electric arc spraying system includes a spraying gun for thermally spraying an inner surface of an object such as a cylinder block by blasting compressed gas substantially perpendicularly to the supplying direction of target wires. The spraying gun is rotated by a spraying gun rotation mechanism. The target wires are loaded in and supplied from wire supplying sources. A wire feeder rotation mechanism is provided for rotating the wire supplying sources synchronously with the spraying gun in rotation. Wire feeders are provided at the spraying gun or adjacent to the wire supplying sources for feeding the target wires. Wire support cables are configured to guide the target wires from the wire supplying sources to the spraying gun.

Abstract: An electric arc spraying system includes a spraying gun for thermally spraying an inner surface of an object such as a cylinder block by blasting compressed gas substantially perpendicularly to the supplying direction of target wires. The spraying gun is rotated by a spraying gun rotation mechanism. The target wires are loaded in and supplied from wire supplying sources. A wire feeder rotation mechanism is provided for rotating the wire supplying sources synchronously with the spraying gun in rotation. Wire feeders are provided at the spraying gun or adjacent to the wire supplying sources for feeding the target wires. Wire support cables are configured to guide the target wires from the wire supplying sources to the spraying gun.

Abstract: A direct current resistance welding machine and a method of controlling the direct current resistance welding machine wherein primary current of a welding transformer is detected when a plurality of switching devices of an inverter are controlled based on corresponding pulses having a predetermined frequency and each having a time width corresponding to the value of a required secondary current. Rise and fall times of the detected primary current are detected. An upper limit frequency Of the primary current is computed based on the time width of each pulse and on the rise and fall times. Thus, the primary current of the welding transformer is controlled by controlling the switching devices based on pulses having a frequency falling within the computed upper limit frequency.