During the last two days of the monitoring thunderstorms were severe in the area and although no interruptions
occurred, four distinct sags were recorded. Over the 12-day period, the maximum-recorded voltage was 246.4v.
The mean was 235v. The regulation was better than ±5%. The low voltage during the most severe sag was
147.6 volts. Only the final event caused the CNC/Machine Tools to shut down. Early investigations had shown
that some equipment shutdowns were coincident with capacitor switching events