Peg from Miami. Client is a plastics manufacturer. Their peak demand is almost entirely driven by one large injection molding machine — 225 kW nameplate. Everything else in the plant is small by comparison. The machine runs two shifts. Any options for reducing the demand impact of a single dominant load?
Client's demand is driven by one piece of equipment — options for reducing
Paul from Minneapolis. When a single machine dominates demand the options are: load shifting if the machine can run off-peak, demand limiting controls that cap the machine draw during peak windows, or operational scheduling to ensure other large loads do not run simultaneously with the machine startup.
Peg again. The machine runs on a production schedule driven by customer orders so shifting to off-peak is not always possible. What about demand limiting on the machine itself?
Paul again. Demand controllers can be installed that watch the running demand within the 15-minute window and shed non-critical loads if the demand approaches a set threshold. They do not reduce the machine's load but they prevent coincident peaks from other loads during the machine's run.
Mark from Houston. Also look at whether the machine's startup inrush can be reduced with a soft starter or VFD. The nameplate rating is the full load running current but the startup spike often significantly exceeds that for a few seconds. On a 15-minute interval the spike is averaged but it still contributes.
Mark the machine is already about 15 years old and has a direct-on-line starter. The maintenance team mentioned replacing the starter at the next major service. A VFD upgrade at that point might be a natural addition.
Mark again. That is the right timing to make the VFD case. Combine the demand savings analysis with the energy efficiency improvements from VFD speed control and the payback period becomes much more compelling than either argument alone.