Technical Bulletin
Page 5 of 8
Regulating Drive – Complete
3.22 Readjustment of Maximum
Working Pressure
1.
Stop the control oil unit.
Warning:
Depressurize
hoses/pipes containing high-
pressure fluids and allow them
to cool to a suitable temperature.
2.
Dismount the supply and return oil
hoses at the rotating oil-seal and short-
circuit the two hoses with the nipple
used previously, see Figure 5.
3.
Close the ball valve placed in the
pressure line just before the outlet
flange in the oil unit and start the oil unit.
Readjust the pressure relief valves at
the control oil pumps at the oil unit
upwards to the original pressure limit at
xxx bar (yyyy psi). Check actual value in
actual set point list in Fan Manual.
4.
Stop the oil unit, dismount the short-
circuit valve and mount the supply and
return oil hoses at the rotating oil-seal.
3.23 Balancing the Counterweight
at the Internal Regulating
Crank Arm
All position numbers refer to drawing
“Regulating Drive – Complete” in Fan
Manual. See example above.
The internal regulating crank arm of the fan is
equipped with an adjustable counterweight
(30) mounted on a lever (29). The
counterweight is mounted to balance the
spring inside of the hydraulic cylinder, which
acts on the pilot valve, forcing it to go out of
position. If not balanced, hydraulic pressure
will result in an uncontrolled movement of the
hydraulic piston.
Adjustment of the counterweight balancing
the hydraulic pressure is done from the inside
of the inner tube of the diffuser. The external
regulating arm must be disconnected from
the actuator by disconnecting the connecting
rod from the external regulating arm.
Balance procedure:
1.
Disconnect the external regulating
arm linkage.
2.
Start the control oil unit.
3.
Place the internal regulating crank
arm in a position approximately in
the middle of the regulating range.
4.
Observe if the piston valve moves
and if so observe the direction.
5.
If any movement is observed,
adjust the counterweight position
at the lever to increase the force
applied to the piston valve in the
opposite direction of the movement.
6.
Repeat the adjustment procedure
by placing the internal regulating
crank arm in different positions,
including the end positions.
7.
When adjusted stop the control oil
unit.
Checkpoint:
Calibration of Regulating Drive Assembly in verification document V213351-9.
