Design Features of AC Variable Frequency Motor Driven Drawworks:
Bearings are roller ones and shafts are made of alloy steel.
●On the drum there is a spiral groove.
●Auto feed driller.
●The main brake is of hydraulic disc type. The disc brake is water or air cooled.
●The auxiliary brake is of motor dynamic braking.
●Single shaft drawworks.
●Transmission is made by two-stage gear reducer and shifting-gear is manual done.
●The gear is pressure lubricated.
Specifications of VFD Single Shaft Drawworks:
| Model | JC40DB | JC50DB | JC70DB | JC90DB | ||
| Nominal drill depth | m | Ф114mmdrill pipe | 2500-4000 | 3500-5000 | 4500-7000 | 6000-9000 |
| Ф127mm drill pipe | 2000-3200 | 2800-4500 | 4000-6000 | 5000-8000 | ||
| Rated power | kW (hp) | 720 | 1440 | 2200 | 3300 | |
| Number × Rated Power (kW) of motors | kW | 1 ×720 | 2 ×720 | 2 ×1100 | 3 ×1100 | |
| Rated Power of motors | r/min | 601 | 600 | 661 | 661 | |
| Dia. of wire line | mm (in) | 32 (1-1/4) | 35 (1-3/8 ) | 38 (1-1/2 ) | 45 (1-3/4) | |
| Max. pull of fast line | kN | 275 | 340 | 485 | 630 | |
| Drum (Dia× Length) | mm (in) | 640×1139 (25-1/4 ×44-7/8 ) | 685×1138 (27×44-7/8 ) | 770×1439 (30 ×56-5/8) | 914×1556 (36 ×61-1/4) | |
| Brake rim (Dia× width) | mm (in) | 1500×76 (59 ×3 ) | 1500×76 (59×3) | 1520×76 (59 3/4) | 1800×76 (70 7/8 ×3) | |
| Power of Motor for Auto Driller | kW (hp） | 45（60） | 45（60） | 45（60） | 45（60） | |
| Transmission Mode | one-reduction single-pinion | one-reduction double-pinion drive ;two-reduction double-gearbox drive | two-reduction double-gearbox drive | two-reduction double-gearbox drive | ||
| Auxiliary brake | Motor dynamic braking | Motor dynamic braking | Motor dynamic braking | Motor dynamic braking | ||
| Overall dimension (L×W×H) | mm | 4230×3000 ×2630 | 4360×3205 ×2825 | 7886×3298 ×2695 | 9300×3300 ×3100 | |
| Weight | kg | 18600 | 26000 | 47500 | 65000 |