Alarm System Controller

Alarm System Controller Redesign Extends Product Life

Alarm panels

The State of California has an extensive water storage and delivery system of reservoirs, aqueducts, power plants and pumping plants that store water and distribute it to 25 million Californians. The system includes 20 pumping plants and 4 pumping-generating plants (www.water.ca.gov/swp).

Aging Electronics Caused High Failure Rate

The alarm system that monitors the pumps was originally designed in the 1960s. The Annunciator Output cards were last manufactured, but not improved, ten years ago by a company now out of business. The aging electronic components in these cards were overheating and causing a high failure rate in the installations, were no longer supported, and documentation was minimal or non-existent.

The California Department of Water Resources (CDWR) asked Stilwell Baker to find modern equivalent components for the Annunciator Output cards. “Not many companies were willing to take this project—they wouldn’t take on the challenge,” said John King, Electrical Planner for CDWR. After investigating the problem, Stilwell Baker recommended redesigning the cards with low power, up-to-date circuitry and components to eliminate the failure mechanisms in the original design.

Onsite Measurements were Key to Proving the Solution

The prototypes worked well in the lab and with the tester provided by CDWR. Yet the initial field trials revealed technical issues in some of the pump stations. Stilwell Baker solved the mysterious issues with system-level modeling simulation and testing, followed by onsite testing and circuit modifications. “With limited documentation available, going onsite was critical,” said Darrel Baker, President and CEO of Stilwell Baker. He continued, “The alarm systems were built in different years with different parts, so onsite measurements were key to proving the solution.”



 New, Reliable, Design is 100% Compatible   

The end result was a fully documented, supportable, and reliable design that eliminated the high temperature components, reduced the overall power dissipation by 24%, and reduced the hot-spot temperatures by 60C (140F). The new design also increased fault tolerance in the output drive stage and now includes short-circuit and over-current protection—so even under a direct short in the system, the alarm circuit would not be damaged.

Stilwell Baker also precisely replicated the original 1960s electrical connector system. The new cards connect directly into the existing alarm system with 100% compatibility of existing systems in the field. Stilwell Baker supports and provides replacement parts, ensuring the alarm system can remain operational for many years to come. John King concluded, “Stilwell Baker came in and solved the problem. This is the best experience I’ve had with a supplier for retrofitting. Stilwell Baker was great to work with.”