Try to turn the compressor by hand. It should be possible to turn it around. It should turn around smoothly, without any 'hickups' (be sure to completely shut down the air compressor!). Check the isolation of the motor windings.
[pdf] The Atlas Copco DM30 II is a crawler mounted, hydraulic tophead drive, multi pass rotary drilling rig featuring a 30 ft (9.1 m) drill pipe change and a standard 4-rod carousel. With a starter rod under the rotary head, the DM30 II has a total depth capacity of 146 ft (44.5 m).
[pdf] On September 13, New Concept Mining (NCM), a division of Swedish company Epiroc, opened its Hydraulic Rock Drill (HRD) production facility in Aeroton, Johannesburg. NCM is a ground support solutions supplier based in South Africa.
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