Abstract: In the conventional arc welding control unit, since the air of the outside of the equipment is applied directly to the whole of the main semiconductor for cooling, there is found a problem that dust, welding fumes and the like can accumulate on or adhere to the conductive portions of the inside of the equipment, which takes time for maintenance of the equipment. To solve this, according to the invention, there is provided an arc welding control unit having a heat radiating unit built in the box body thereof for discharging the air heated by a heat generating first electrical element to the outside. The heat radiating unit has a tunnel-type shape including an outer peripheral portion for defining a cavity portion allowing the air to flow therethrough, whereby dust, welding fumes and the like can be prevented from accumulating on or adhering to the conductive portions of the inside of the equipment.

Abstract: A semiconductor laser heating apparatus has a measuring instrument for measuring an optical-power output relative to a current to be supplied to the semiconductor laser. The heating apparatus also has a calculator for calculating a correction coefficient of the optical-power output based on the measured data, and has a controller for correcting a supply current to the semiconductor laser relative to a value determined by an optical-power output determiner based on the calculation result. The heating apparatus employing optical fibers as an output terminal thus can always produce a desirable heating condition regardless of the optical-power output deteriorated with the lapse of time.

Abstract: A brake release circuit of an electromagnetic brake for locking a motor and an indication circuit for indicating a brake release are coupled together. Both the circuits may be turned on and off by a single switch contact. A motorbrake release device secures space saving and high safety, and is economical.