Turbine Maintenance Techniques Flashcards
What is “torquing”? How is it difference than tension?
Torque is a rotational forces and tensioning is a stretching force.
(Torquing is about stretching the bolt or stud by turning the nut
This pulls the shank due to the thread’s ramp angle. The, friction
between the nut and component hits a predetermined amount.)
What is “tensioning”? How is it difference than torque?
Tensioning is the force of stretching,
not rotating a nut.
(Tensioning does not turn the nut. To mount a tensioner, the full height of threads must equal the thickness of the nut above the nut. When hydraulic pressure is applied, the pulling cylinder stretches the bolt. Once the threadèd
shank is stretched, seat the nut and remove the pressure.)
What is the 10% bolt maintenance method?
Each year, tighten (torque/tension) 10% of the number of bolts, then next year move down 1 bolt number and tighten 10% more.
Regarding alignment of the wind turbine gearbox to the generator, which can be moved and which can not?
Generator can be moved
Gear box can not be moved
What is SCADA and how do wind turbines use it?
“Supervisory
Control
And
Data
Acquisition
SCADA is a control system architecture comprising computers, networked data communications and graphical user interfaces for high-level supervision of machines and processes. It also covers sensors and other devices, such as programmable logic controllers, which interface with process plant or machinery.”
Source: https://en.wikipedia.org/wiki/SCADA
What is a “Clamp on Meter” and what does it do well?
A clamp meter can measure amps, ohms of resistance, volts of current, and hertz using electricities electromagnetic fields. Breaking into the circut is not needed.
This meter measures current in volts the best.
Where do do DC circuits originate?
At the power supply
Before working on an electrical part how do you test for voltage?
1) Test your multimeter fuses by…
2) Do a Hot-Cold-Hot multimeter voltage check: Test all phases with circuit hot, then power off and test voltage of all phases, then check your meter by testing another similar circuit that is still like to rule out a blown meter.
On a 3 phase system test:
N-1
N-2
N-3
1-3
2-3
2-1
How do you do a multimeter fuse test on a Fluke 87?
Fuse Test
Dial to V
Red lead to A: beep = good fuse
Red lead to mA, Beep = good fuse
How do you re-reference the rotor blade pitch position sensor?
With the blade at the 0° position (indicated by vernier at blade root) compare with the position indicated by the pitch control system. If the deviation >0.5°, re-reference the rotor blade
What can “additional noise emissions” from a moving blade indicate?
D.U.D.E !
- Damage on the rotor blades
- Unrepaired transit damage
- Dirt accumulation
- Erosion of the blade
What is done for an external blade inspection?
Inspect the external part of the blade. In doing so, check the following:
• Blade tip
• Trailing edge
• Surface of the blade
• Lightning strikes
• Cracks
• Coating damage
• Erosion
• Cleanliness
• Blade root
- Function Test: From a safe distance and with the rotor spinning, listen for abnormal noise or vibration.
1) How do you mark a torqued bolt?
2) What colors should be used for what occasion (Red, Blue, black)?
All torqued bolts must be marked with a single line running down the side of the bolt head, across the washer and onto the clamped part, with an oil-based paint marker.
2) For installation, blue is preferable for a first torque and always use red for installation torque inspections
When inspecting bolt connections during annual maintence, the stud _______ ___ ________ through seating of the stud, but it is not normal for nuts to actually ______ __ ___ ____ from operation.
1) tension may decrease
2) rotate on the stud
Under normal conditions, the stud tension may decrease through seating of the stud, but it is not normal for nuts to actually rotate on the stud from operation.
If any nuts have misaligned paint marks, document the position and estimated degree of movement of effected studs.
During annual maintenance, It is common for the nuts to rotate __ to __ degrees beyond the earlier
torque mark
It is common for the nuts to rotate 0 to 20 degrees beyond the earlier
torque mark
What happens if you fill a component with too much grease?
What also helps when greasing bearings?
It can push the seal off.
It is better to rotate bearings while greasing.
Calculate the pressure in psi needed to torque a 5.4 square inch piston tool to 75,000 foot pounds of force on a foundation bolt.
Pascal’s Law
Pressure = Force divided by Area
PSI = 75,000 ft. Lbs. / 5.4 sq. In.
= 13,888 psi ?
Area of piston tool (size of tension tool 5x9 piston = 5.4 sq. inches
75,000 ft. pounds
Force
Name the parts of a “low profile hydraulic ratchet”. What is another name for it?
- Ratchet
- Piston
- Reaction Arm
Stealth Head
1)Try to list all the 11 parts of a yaw piston assembly from top to bolt head to bed plate
2) and torque requirement
1) Adjusting Bolt/Screw
2) Lock Nut
3) Plastic pins / Tubber plugs
4) Retaining Ring / Snap Ring (keeps from walking out)
5) Tapped / Threaded Bushing
6) Spring Pack (contains Thrust piece, Disk springs / Compression washers (arced), O-Ring on top)
7) Shim Ring (at bottom of piston_
8) Brass Piston / Piston Bushing
9) Piston O-Ring
10) Puck
11) Bed plate sleeve
100 Nm of torque + 300 degrees of angle
What is the term for when a torque spec has newton meters and degrees of rotation?
Torque and Angle
How may pistons support a GE 1.x nacelle?
12 piston assemblies
1) How many “flats” does a standard bolt head have?
2) How many degrees is each?
1) 6 flat sides
2) 1 flat corn to corner = 60degrees
2 = 120
3 = 180
4 = 240
5 = 300
6 = 360
When doing a yaw puck tensioning, what should you do before tensioning?
Inspect the pucks
What does the acronym BIM represent?
Describe what it means.
Break-In Maintenance
BIM tasks may begin after 360 operating hours post-COD and must be completed within 5 months from the completion of those 360 operational hours.
