300 kVA AVC Recovers ₹3.9L/Year at a Precision Engineering Plant
1. Background & Setup
A precision automotive component manufacturer in Pune operates high-speed Haas and Mazak CNC turning centers. These machines run 24/7 to meet strict delivery timelines for major OEMs. Any supply voltage drops or spikes cause the machines' controller drives to trip, ruining semi-finished blocks and stopping production.
2. The Challenge & Downtime Costs
The facility suffered from severe incoming voltage drops (sags down to 340V) caused by grid switching in the local industrial area, as well as transient voltage swells from neighboring heavy casting units. Over-voltage trips occurred up to 5 times per week. The estimated downtime cost was ₹15,000 per hour, including broken carbide inserts, material waste, and labor idle time.
3. Technical Diagnosis
Power logging showed incoming voltage sags of 15% lasting between 30ms and 80ms. These sags fell outside the tolerances of the CNC servo drives, forcing them to trip. Additionally, regenerative braking spikes from the spindle motor during deceleration were adding to the over-voltage condition, making slow-correction regulators useless.
4. Active Transformer Solution
We installed an Active Transformer 300 kVA Automatic Voltage Controller (AVC) featuring high-speed digital tap correction. Unlike standard stabilizers that take hundreds of milliseconds, the AVC corrects grid fluctuations within 10ms. This prevents the supply voltage from crossing Haas and Mazak safety thresholds.
Measured Outcomes
- CNC over-voltage and under-voltage trips reduced to zero.
- Annual savings of ₹3,90,000 in material scrap and tool insert costs.
- Eliminated 120 hours of unplanned tool room downtime per year.
- Full capital cost payback achieved within 18 months.
Automatic Voltage Controller (AVC)
We design, test, and commission these systems to match unique industrial loads and environmental parameters.