Raisebore upgrade drives Edilmac on

• Published in: Tunnels & Tunnelling International no. NOV; pp. 17 - 20
• Main Author: JONES, Maurice
• Format: Journal Article Trade Publication Article
• Language: English
• Published: Sidcup Progressive Media Group 01-11-2011; Compelo
• Subjects: Applied sciences; Buildings. Public works; Construction equipments; Construction works; Cooling; Drilling; Exact sciences and technology; Hydraulics; Packaging; Power; Stone; Italy; Europe; Mining; Excavating; Borer; Characteristics; Upgrading; Construction equipment; Limestone; Product development; Rehabilitation; Hydraulic drive
• ISSN: 1369-3999

"The limestone rock here at Sedrina is much harder (around 160 MPa UCS) and massive,' says [Adriano Facchinetti], "so it will be a real test for the new rig (compared to Chiacio). But it now has a high power at 450 kVA instead of 350 kVA. We are a lot happy with the 'new' rig. Really a lot happy. It really is an improvement in performance on the old 73R. The rod handling system is also a little better, but the real improvement is in performance." "After trials, Edilmac has a preference for AC electric motors, due to their higher efficiency compared to hydraulic motors or DC electrics, which means variable frequency (VF) drive control," explains Lyly. "An AC motor with VF control can be adjusted for speed and torque similarly to a DC motor, but with the higher efficiency. It was decided to go for a complete upgrade with modern equipment, not only for the drive but for control and cooling systems." The new package has been backed by a lot of internal development at Atlas Copeo. "We hadn't built a raiseborer with a variable-frequency electric drive at Atlas Copeo since 2002, and there has been a lot of component development in the meantime," explains [Johnny LyIy]. "So we had to test the whole drive-train first. Using a new, water-cooled compact motor, we carried out the tests over two days with the powerpack at the premises of the motor manufacturer ENn in Austria, with our system connected to a load motor for simulations. These included stalling, backspin and fluctuating load to simulate all the conditions that might occur with a raiseborer. And the results were very good, meaning we could go ahead with the retrofit work. "In the meantime Edilmac had fitted the new gearbox themselves, and so we put the two together at their Gorle premises, carrying out further successful tests for another two days," reports LyIy. "One result was a big increase in torque to 250 kNm. The rig could then be designated as an Atlas Copeo Robbins 73RVF C."