The conventional large-current circuit board, with the bus-bar arranged on the board and dipped into the molten solder, had problems such as bending of the PCB, electrical and mechanical reliability.
In the case of the newly developed large-current board, the bus-bar and circuit parts are connected by the fasteners of the caulked parts, so that a large-current circuit of max. 500 A and a signal circuit can be printed on one piece of PCB. Further, the bare copper bar, used for wiring, provides high heat radiation effect, ensuring temperature rise at any part of the PCB after 5000 hours of the continuous flow of rated current to be below 15C, and assuring high reliability. The adoption of the newly developed technology brings about the effects given below.

1. With the large-current circuit connected to the PCB of signal circuit, the mounting density gets improved, allowing miniaturization of the device.
2. The adoption of bare copper bar allows automatic assembly of the device.
3. The three-dimensional wiring of circuits allows more freedom at the time of design, enabling denser wiring than the two-dimensional wiring.

1. Control unit for NC machine tool
2. General-purpose inverter large-current power supply unit