Please see attached video of the gearless conveyor drive operation at Antapaccay:

http://videos.bulk-online.com/video/...Conveyor-DriveGearless Conveyor Drive ■

....the REI/Anderson Strahclyde drift belt at Selby, which was in operation in the early 1980's, was gearless. Perhaps 8000th^-1 is small scale to Peru but it was impressive to Yorkshire (who came 3rd in the Olympics medal count as well. God's County in fact.) ■

You should also remember some additional facts about 1984-1985 12.2 km x 800 m ( by memory) Selby Incline designed by Anderson-Stratclyde & REI:

1. Two 5050 kW electric motors on one head pulley

2. Belt Speed 8.4 m/s using a 2500 mm diameter head pulley

3. Motors were from a standard diesel locomotive design

4. Gravity take-up with capstan control during stopping

5. Coal Capacity = 2500 t/h from multiple loading points -- NOT 8000 t/h as noted by Louispanjang in another thread.

6. Belt Strength ST-7100 N/mm operating at SF ~ 5.5:1 with pipe organ splice pattern - supplied by BTR (UK)

7. First use of cable strippers and precast splice pattern - x-rayed and found exceptional repeatability and tracking control

8. Idler spacing 6 m carry & return

9. Idler diameter ~168 mm with special machining and balancing.

10. See this for some added reference material - http://www.saimh.co.za/beltcon/beltcon2/paper212.htmlpaper212.html - final capacity was 2500 t/h with nominal at 1800 t/h.

11. Special Note: The installation did not achieve full length of 14.9 km due to sea acquifier flooding. It only achieved about 12.2 km by memory.

Installed before Prosper Haniel and became the model used by O&K to design Prosper Haniel - O&K visited Selby to give guidance on their quest together with Phoenix in their belt design techniques.

What happened to this incline belt components??? A new BTR belt was installed near the end of drift conveyor's life.

SELBY was a copy-cat of an earlier dual conveyor piggy-back drift conveyor also designed by Huwood ( by memory- maybe in conjunction with REI). I was privileged to receive a copy of the drawings from Huwoood for this mine and also REI drawings for Selby given by British Coal Board.

Some facts that were published before Selby was commissioned. http://www.saimh.co.za/beltcon/beltcon2/paper212.htmlpaper212.html ■

It is worth noting that Siemens gear-less drives are sold to a single conveyor manufacturer and not available to other manufacturers for their use. A very foolish marketing strategy. On the other hand such drives fit into a very narrow window of application, between the largest available reducers and the highest available belt tensions.

Joe Dos Santos ■

Joe,

There are other suppliers of gearless drives. ABB, Toshiba, and others, ... ABB has teamed with Takraf. CDI has teamed with TMEIC (Toshiba, Mitsubishi). Krupp is not the only player.

I agree with you that Siemens will diminish their marketing scope with this strategy for all drives, not only gearless. ■

Larry,

Honestly, it has not yet been an issue for us as we have not been in the narrow window that I mentioned. We thought we were in a particular application and when I pursued it, with both Siemens and ABB I found that both were locked in to Krupp and Takraf respectively. I was not aware that Toshiba offers gearless drives. To me it is just equipment that should be offered to anyone who wants it. Doing otherwise is limiting market access.

Joe Dos Santos ■

HI joe,

My point was that there are other providers of gearless drives. We found TMEIC after searching the industrial installations on gearless drives, not necessarily conveyor drives. We have continued to explore what, when and how. We would welcome your further interest and others who also wish to become interested in gearless drives for belt/pipe conveyors.

As I said before, the drive rating per motor must exceed 2500 kW to become $$$ competetive. There are companies that can assess benefits beyond $$$, but, they are not the many. ■

Larry,

Thank you. I am definitely interested though I don't often come across such high powered applications. I have long been aware of the gear-less drive technology as utilized in deep mine hoisting for many years. That is how REI and Anderson Strathclyde got there on the Selby project.

Joe Dos Santos ■

The Antapaccay drive pulleys were very interesting to design. The pulley shaft being the motor shaft adds some unique criteria to the design. The rotor was a very large mass attached to a the end of the pulley. The shaft extension is quite long with no supporting bearing on the other side of the rotor. Creating a very large overhung load.

The air gap between rotor and stator must be maintained so the shaft deflection at the rotor become a defining criteria in the size of the shaft, which in turn dictated the locking device sizes, and the end disc shape.

Later design requirements demanded a higher torque capacity at the locking devices. This ultimately became the determining factor in the component sizing and end disc design. The final bearing size being 750mm bearing assemblies.

Randy Smyth

Dir. Technical Operations

RAS Industries ■

Roland

Thanks for the kind words. In answer to your questions:

1) The analysis of the motors and what its output will be on the system was done between Krupp and Siemens. We were only presented with the resulting pulley loading and torque requirements for both starting and braking. Which style calculations they used to get to those results i am not aware of.

2) The bearings are typical double row spherical. And you are correct that the internal radial clearance in the two bearings is enough to put the air gap out of tolerance. Although this will only be the case when the belt tension is off the pulley. In this situation the overhung load has the drive side bearing loaded downwards and the outboard bearing loaded upwards, resulting in an air gap out of tolerance. Once belt load is applied to the pulleys both bearings are loaded in the same direction at 90 degrees to the OH load which brings the air gap back into tolerance. The air gap was/is monitored and last word I had was that everything was running as calculated.

3) As above, the torque requirements for the brake were given to us after all calculations were done between Krupp and Siemens so all we received was a max torque requirement. I don't recall the brake torque requirement but in the end, the defining factor for the pulley design was the requirement that each locking device meet 4x the torque generated by the 3.8 MW motors.

It was a fun project. The large unique ones like these are always a welcome diversion for the engineering team from the more day to day pulley designs. Same with designing pulleys for ST10,000 belts of the near future.

Randy Smyth

Dir. Technical Operations

RAS Industries ■