VFD Speed Analysis (Exhaust Fan)
Objective/Method/Outcome
Objective: Analyzes the speed of the exhaust and sorts it into 1 of 5 bins based on speed and determines if the speed exceeds 85% for over acceptable time.
Method: Finds the percent the recorded VFD speed is to the maximum and sorts it into bins and creates CTLs. Further, finds the potential savings if the VFD speed is over 85% for more than the acceptable amount of time.
Outcome: Calculates the Calculated Trend Logs for each bin and the potential savings if the VFD speed is over the threshold for more than acceptable time.
Description
Sort VFD Speed signal into one of the four different bins (less than 20% (VFD off), 20-50%, 50-70%, 70-85%, and greater than 85%). Generates an insight if the VFD operates consistently above 85%.
This rule is part of the CopperTree Standard rule-set.
Default Priority
Medium
Diagnosis
- Review if speed control is manually overridden.
- Review fan speed control sequence.
Message
Exhaust Fan VFD is operating above 85% for more than 60% of the daily operation time.
Rule Template
Insight Type: Integrity KPI
Trigger Type: Active High
Logic
Inputs
| Input | Unit | Tags | Description |
|---|---|---|---|
| VFD Speed | Exhaust Air Fan VFD Speed | The recorded VFD speed | |
| Threshold – Allowable Operation Time Above 85% Speed | % | The minimum amount of time above 85% that is required to trigger insight | |
| Cost per Hour | $ | The Energy consumption cost per hour | |
| Days of operation annually | The days VFD is active per year |
Notes
VFD are generally sized to operate between 50% and 70%.
Threshold – % of Allowable Operation Time Above 85% Speed – 60%