# Tensioning Operation

The following is a general tensioning procedure, which must be augmented by the wind turbine manufacturer (OEM) turbine specific assembly instructions. In each step of the general procedure where it is required to reference the OEM assembly instructions, a reference to this fact is made.

Verify that all parts are assembled correctly and all connections are properly made with coupling locking collars tightened (where available).

1. Start the electric pump. The pump will start to run and pressure will build up slowly in the system. Continually check the pressure. Continually check the top part of the puller bars, the protruding puller bar represents the stroke of the hydraulic pistons inside the tool. If the red over-stroke warning line becomes visible on any of the tools prior to reaching the OEM specified pressure, immediately stop the pump and refer to step 2.

2. While the pump is running, check the extension of the pistons. If the red over-stroke line appears, stop the pressurisation, Proceed with Steps 4 & 5 then proceed to Step 1.

3. When the pressure level as specified by the wind turbine OEM is reached, stop the pump, the pressure should hold steady.

4. Tighten the hexagon nuts down against the joint face using the square drive on the gearbox shaft.

   Turn the Shaft clockwise to tighten. The applied torque must not exceed 30 Nm.

5. Slowly release the hydraulic pressure to zero. The tensioners are fitted with an automatic reset mechanism, which allows the pistons to retract after depressurisation. Monitor the puller protruding out of the top face of the tool. Once the pressure is released, the puller bar will begin to withdraw, so it becomes level with the top face of the tensioner again. Only continue once the pullers are flush with the top face of the tensioner.

6. To ensure a good tightening result, repeat the tensioning operation section step 1 up to step 5.

7. Transfer the tensioners to the next stud bolt. Do not disconnect the harness during this transfer.

8. Start the pressurisation sequence step 3 to step 7.

9. Before disconnecting any hoses, check that all the puller bars are flush with the top face of the tool.

10. Remove the hoses.