2 years ago

MOTOREX Magazine 2020 117 EN

  • Text
  • Sunil
  • Engines
  • Lubrication
  • Oils
  • Products
  • Motor
  • January
  • Lubricant
  • Hydraulic
  • Motorex


REPORT CONTINUED Preparatory work is carried out in the maintenance shaft above before the fan is removed. With the tunnel closed, the huge steel fire protection cover is removed. Assisted by two trucks, the lowboy is ready to receive the load. Once released, the fan is lowered hydraulically onto the lowboy with centimeter precision. tight as, after four hours, the nearly 30-tonne fan is lowered from its chamber onto a specially designed lowboy trailer. Workers position the trailer with centimeter precision using lasers and hydrodynamic steering. Next a police escort accompanies the lowboy to the Flüelen maintenance center. The lowboy is driven by a three-axle tractor truck at each end; the whole rig weighs over 110 tonnes. LUBRICATING THE ROTOR BEARINGS The biggest of the fans is driven by a 2,920-kW electric motor. The rotor is surrounded by oversized tapered roller bearings at the front of the motor. Since these bearings can only be replaced when the fan is dismantled, they are designed to last a good ten years. Extreme temperature fluctuations, high bearing pressure, and a warm, humid climate make lubrication a challenge. When the Uri cantonal construction department, responsible for tunnel maintenance, found excess wear on the bearings, it turned to MOTOREX for advice. Following a battery of analyses, the task was accomplished using multi-range MOTOREX Corex HV 100 industrial and hydraulic oil. Lubricant is supplied to the bearings from above and to the 14

The fans are carried to the maintenance center and back to the tunnel on a special lowboy trailer. After 80,000 hours of operation, the bearings are still within tolerance levels. Once fully overhauled, a three-month process, the fan is placed in storage as a replacement unit. Use of an induction heater ensures that the renewed bearings are properly installed. side by injection in a closed-circuit system. It flows over the bearings into an oil sump where the lower part of the bearing is continuously lubricated and cooled. MOTOREX Corex is ideal for use in fluctuating low and high temperature conditions. Its extreme shear stability and long-lasting anti-corrosive properties make Corex HV 100 the perfect choice for the Gotthard Tunnel. OVERHAUL WITH KNOW-HOW By now each of the fans in the Gotthard Road Tunnel has undergone a general overhaul three times on a rotating schedule. These overhauls are performed in accordance with manufacturer’s directions at the Flüelen maintenance center. Once the fans have been dismantled and cleaned, all movable parts are measured and those subject to wear are replaced, including the bearings. Even after ten years in service with MOTOREX lubrication, they show only minimal striation. “That’s reassuring,” says Michael Zgraggen, the man responsible for the smooth functioning of the Gotthard Road Tunnel’s mechanical systems for over 25 years. For him, the only thing that counts is absolute reliability. • MOTOREX MAGAZINE 117 I JANUARY 2020 15



MOTOREX Magazine - Deutsch

MOTOREX Magazine - Français

MOTOREX Magazine - English