Wind Turbine Drivetrain Vibration Analysis

Evaluates drivetrain vibration health across three subsystems: main bearing, gearbox, and generator.

When to Use

Load this skill when the user wants to: - Assess drivetrain vibration health from CMS or SCADA data - Interpret RMS, peak-to-peak, or spectral findings for main bearing, gearbox, or generator - Correlate vibration alarms with operational events - Decide whether to continue operating, increase monitoring, or shut down

Drivetrain Components

Component	Sensor Location	Key Frequencies
Main Bearing	Non-drive end, drive end	BPFO, BPFI, BSF, FTF
Gearbox LSS	Low speed shaft	Gear mesh (LSS x teeth), bearing defect freqs
Gearbox IMS	Intermediate shaft	IMS gear mesh harmonics
Gearbox HSS	High speed shaft	HSS gear mesh, bearing defect freqs
Generator NDE	Non-drive end bearing	Electrical harmonics, bearing defect freqs
Generator DE	Drive end bearing	Bearing defect freqs, rotor unbalance

Vibration Thresholds (ISO 10816 / CMS Reference)

Location	Normal	Warning	Critical
Main Bearing RMS (g)	< 0.3	0.3 - 0.8	> 0.8
Gearbox HSS RMS (g)	< 0.5	0.5 - 1.5	> 1.5
Gearbox LSS/IMS RMS (g)	< 0.3	0.3 - 1.0	> 1.0
Generator RMS (g)	< 0.5	0.5 - 1.2	> 1.2
Peak-to-peak step change	< 10%	10-30%	> 30%

Note: Always evaluate against site-specific baseline. A 20% rise from stable baseline is more significant than an absolute value alone.

Frequency Fault Signatures

Fault	Frequency Signature
Bearing outer race (BPFO)	(N/2) x (1 - d/D x cos a) x RPM
Bearing inner race (BPFI)	(N/2) x (1 + d/D x cos a) x RPM
Gear mesh	number of teeth x shaft RPM
Gear mesh sidebands	GMF +/- shaft frequency
Rotor unbalance	1x RPM dominant
Misalignment	2x RPM dominant, axial component
Looseness	Sub-harmonics (0.5x, 1.5x) or high harmonic content

Severity Scale

Severity	Label	Description	Action
1	Healthy	All values normal, stable trend	Continue normal operation
2	Early warning	1-2 parameters in warning zone, stable	Increase CMS polling frequency
3	Moderate	Multiple warning flags or single critical	Inspect within 2 weeks
4	Significant	Critical zone or rapid trend growth	Plan shutdown within 48-72 hours
5	Critical	Multiple critical flags, step-change	Immediate shutdown required

Procedure

Collect inputs: CMS trend (last 30-90 days), current RMS and peak-to-peak per component, frequency spectrum findings, SCADA alarms, operational context.
Evaluate RMS values against thresholds. Flag Warning or Critical zones.
Analyze trend:
Stable: value in warning zone but flat for >30 days = lower urgency
Gradual rise: value increasing steadily = schedule inspection
Step change: sudden jump >30% = treat as Critical regardless of absolute value
Interpret frequency spectrum if available:
Match dominant peaks to fault signatures table
Note sidebands around gear mesh frequencies
Note sub-harmonics or 1x/2x dominance
Correlate with SCADA alarms and operational events.
Assign severity per component, then determine drivetrain-level severity as highest.
Generate output report using the format below.

Output Format

=== DRIVETRAIN VIBRATION REPORT ===

ASSET : [Turbine ID] SITE : [Site name] DATA PERIOD : [Date range of CMS/SCADA data] MISSING DATA : [List any unavailable inputs]

MAIN BEARING: RMS : [value] g - [Normal / Warning / Critical] Trend : [Stable / Gradual rise / Step change] Spectrum : [Key findings or not available] SCADA Alarms : [Count and type] Severity : [1-5] - [Label]

GEARBOX (LSS / IMS / HSS): RMS : LSS [value] g / IMS [value] g / HSS [value] g Trend : [per shaft] Spectrum : [Key findings] SCADA Alarms : [Count and type] Severity : [1-5] - [Label]

GENERATOR (DE / NDE): RMS : DE [value] g / NDE [value] g Trend : [per bearing] Spectrum : [Key findings] SCADA Alarms : [Count and type] Severity : [1-5] - [Label]

DRIVETRAIN SEVERITY : [1-5] - [Label] SHUTDOWN : [Yes / No / Conditional]

FAULT HYPOTHESIS: - [e.g., HSS bearing outer race defect - BPFO peak confirmed at X Hz] - [e.g., Gear mesh sideband modulation - possible gear wear or load variation]

RECOMMENDED ACTIONS: - [e.g., Increase CMS polling to daily for HSS channel] - [e.g., Oil sample with ferrography within 72 hours] - [e.g., Plan HSS bearing replacement at next scheduled outage]

ESCALATION TRIGGERS: - [e.g., RMS exceeds 1.5 g on HSS - immediate shutdown] - [e.g., Step change >30% on any channel - treat as critical] - [e.g., New BPFO or BPFI peak confirmed in spectrum - escalate to Severity 4]

Cross-Skill Correlation

If gearbox visual data is available, load wind-turbine-gearbox skill and cross-correlate: - High Fe ppm + rising HSS vibration = active wear confirmation - Spalling in borescope + BPFO peak in spectrum = bearing failure progression - Normal oil + rising vibration = early fault not yet generating debris (higher urgency)

If blade inspection data is available, check for rotor imbalance: - 1x RPM dominant in main bearing spectrum + blade damage = aerodynamic imbalance - Asymmetric blade damage across A/B/C = mass or aerodynamic imbalance source

Pitfalls

Do not evaluate vibration in isolation. Cross-reference with oil analysis and visual inspection.
A single high RMS reading during a storm or grid fault is not a fault indicator. Check operational context.
Spectrum analysis requires RPM-normalized data. Raw frequency peaks are meaningless without shaft RPM.
Generator electrical faults can appear as vibration. Check electrical data before attributing to mechanical cause.
Stable high RMS is less urgent than rapidly rising moderate RMS. Trend rate matters more than absolute value.

Verification

After generating the report, confirm with the user: - Does the severity match CMS system alerts or OEM recommendations? - Is shaft RPM data available to normalize spectrum frequencies? - Are there recent maintenance events that could explain vibration changes? - Is SCADA power curve deviation consistent with vibration findings?

vibration-analysis

Installation