In the figure, a power supply system with a conductor bar can be seen, where a motor-driven cable reel for hazardous areas is installed for medium-voltage tunnel applications.

The system supplies a tunnel boring machine (TBM) with an approximate power of 3 MW, using explosion-proof junction boxes with Ex db protection.The EX protection type of the system is Ex h – ATEX category I M2, and the same design can also be developed according to the IECEx scheme.

The special motor-driven cable reel consists of a painted steel drum, on which a robust, flexible medium-voltage cable (12/20 kV) is wound.

The drive system is powered by a motor-gearbox assembly and the cable winding and unwinding operations are controlled by a dedicated electrical control panel.

The core component of the motor cable reel is the slip ring, which is housed inside an Ex db flameproof enclosure.

This high-performance slip ring is designed for heavy-duty environments and is significantly more compact than competing products.Its uniqueness lies in the fact that the active parts are not air-insulated, but instead isolated through a multi-layer insulation system, enabling the slip ring to reliably withstand high voltages up to 24 kV and maximum currents of approximately 680 A.

This high-voltage slip ring with insulated active parts is a patented technology of SPM Special Machine, allowing the company to meet new challenges in markets requiring extreme engineering solutions..

SPM Special Machine Srl – Collettori rotanti elettrici e avvolgicavo