calculate_bearing_characteristic_frequencies
Compute bearing fault frequencies (BPFO, BPFI, BSF, FTF) from bearing geometry and shaft speed to diagnose machine faults.
Instructions
Calculate bearing characteristic frequencies from geometry.
Uses formulas from ISO 15243:2017 and SKF bearing handbook.
Essential for bearing fault diagnosis when you know bearing geometry
but don't have pre-calculated frequencies.
**IMPORTANT - LLM Usage Guidelines:**
- This tool REQUIRES exact bearing geometry parameters
- DO NOT guess or estimate bearing geometry if not provided
- DO NOT use "typical" or "standard" values without user confirmation
- If geometry is unknown, tell user to:
1. Check manual using read_manual_excerpt()
2. Look up bearing in manufacturer catalog (e.g., SKF, FAG, NSK)
3. Use lookup_bearing_in_catalog() if bearing designation is known
4. Measure the bearing physically if necessary
- ONLY calculate with geometry explicitly provided by user or found in manual
- DO NOT make assumptions about contact angle (use 0 deg if unknown and inform user)
Args:
num_balls: Number of rolling elements (Z)
ball_diameter_mm: Ball/roller diameter (Bd) in mm
pitch_diameter_mm: Pitch circle diameter (Pd) in mm
contact_angle_deg: Contact angle (alpha) in degrees (0 deg for deep groove ball bearings)
shaft_speed_rpm: Shaft rotation speed in RPM
ctx: MCP context
Returns:
Dictionary with BPFO, BPFI, BSF, FTF in Hz
Example:
>>> # For SKF 6205 bearing at 1797 RPM
>>> freqs = calculate_bearing_characteristic_frequencies(
... num_balls=9,
... ball_diameter_mm=7.94,
... pitch_diameter_mm=34.55,
... contact_angle_deg=0.0,
... shaft_speed_rpm=1797
... )
>>> print(f"BPFO: {freqs['BPFO']:.2f} Hz")
BPFO: 81.13 Hz
Common bearing geometries:
- Deep groove ball bearings: contact_angle = 0 deg
- Angular contact bearings: contact_angle = 15-40 deg
- Cylindrical roller bearings: contact_angle = 0 deg
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| num_balls | Yes | ||
| ball_diameter_mm | Yes | ||
| pitch_diameter_mm | Yes | ||
| contact_angle_deg | No | ||
| shaft_speed_rpm | No |
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||