Fuse Program Helps Plant Put the Brakes on Maintenance Costs
When Dana Inc. bought a Canadian brake-manufacturing plant in St. Catherines, Ontario, the company soon realized it had a major maintenance problem in the 144,000-square-foot facility. Electrical-system costs were hitting $110,000 per year, and motor burnouts, motor rewinds and nuisance outages were limiting the plant’s operating efficiency. The culprit behind many of these problems turned out to be one of the basic building blocks of power protection, the plant’s fuses.
The plant was maintaining a large inventory of fuses to serve the 1,600 motors its operations require. Ranging from 1 hp to 450 hp, these workhorses power everything from CNC machine tools and high-capacity pumps to the conveyor system that moves foundry sand to the production floor. The challenge of managing the variety of fuses plant managers had thought their equipment required was proving overwhelming to maintenance personnel. Fuses were constantly being replaced, but not always with an exact match. And because the inventory contained so many part numbers from so many manufacturers, it was difficult to know which fuse was appropriate for any given application.
The plant’s electrical coordinator contacted a local fuse distributor for help. The distributor advised switching to a single manufacturer. The product selected includes both a time-delay feature to allow for motor-startup surges, while still providing vital current-limitation capabilities. Previously, the plant had selected fuses based on their ability to serve one of these purposes or the other. The new approach allowed for significant inventory reductions-down to $6,000 from the previous $27,000 figure.
In addition to cutting inventory costs, reducing the number of product numbers stocked has made selecting the right fuse easier for maintenance staff. A large proportion of the plant’s troubling equipment outages had been caused by previous improper fuse substitutions. The new fuses have led to significant reductions in what had been a $2,000 monthly fuse-replacement bill.
Fuses also can be more appropriately matched to the equipment it’s powering. The new fuses have 300,000-amp interrupting rating, as opposed to the previous models’ 200,000-amp rating. Previously, to address limited short-circuit capabilities, Dana routinely had used fuses rated 175 percent to 200 percent higher than a motor’s full-load rating. This practice led to regular motor burnouts. Today, Dana is able to match fuses much more closely to the full-load rating, cutting annual motor-rebuild costs to $35,000 from $98,000 per year.
And when fuses do blow now, the maintenance staff is able to replace them faster. The fuses incorporate an indicator “window” that darkens when the fuses fail. This has eliminated the need to power down an entire panel to test for failed fuses, an important cost saver for the manufacturer.
From Pure Power, Winter 2002