DBS series rig, such as the AC VFD rig, right now is the main competitive product made by HH, which features reliable performance economic efficiency, high degree of automation, and reducing the labor intensity a lot while making the drilling activity much safer.
DBS series rig driven by AC motors which has wide rotation speed adjustment and big torque output characteristics, esp. satisfy the working to conditions for drawworks, mud pump, rotary table and top drive system and explosion proof area.
Owning to function of dynamic braking and Max.torque output at zero rotation speed, DBS series rig achieved higher efficiency of the drilling activity and much safer assurance compared with traditional mechanical or SCR rig.
The DBS series rig, such as the AC VFD rig has higher transmission efficiency and power factor, leading to less electricity power consumption. Simplifying mechanical transmission structure, making the mechanical maintenance work more easier.

The first AC VFD (DBS) rig made by HH was delivered in the year 2002, up till now, more than 400 such rigs have been put into operation around the world.