Vicor Applications Engineering Puts Power Solution on the Right Track
Just about everybody has first-hand experience making a moving thing slow down or stop – perhaps with a car, a bicycle, or a washing machine. You simply put on the brakes or shut off the power. But the process becomes much more complicated when the moving thing is a train, an aircraft, a turbine for a hydroelectric plant, or even many smaller things. The braking mechanisms come in a wide variety: air brakes, disc brakes, electromagnetic brakes, regenerative brakes, drum brakes, and, of course, anchors.
The Vicor customer manufactures industrial brakes, including friction materials, brake blocks, brake shoes, brake linings, clutch facings, to name a few. The applications for these products include automotive – cars, trucks and racing cars – nautical, hydroelectric, industrial, and agricultural.
The power application was the redesign of power supply used in a brake control system for a train. The reason for the redesign of the existing discrete was an extremely high failure rate due to thermal issues. The difficulty of manufacturing the existing design was the main reason to seek a modular solution rather than discrete solution.
They began their own redesign with a 110 V input and two outputs, 24 Vout (a VI-JT3-IW) and 5 Vout (a competitor module). Both were mounted face to face, one on top of the PCB, and one on the bottom. The Junior baseplate was glued to the chassis inside an hermetically sealed aluminum enclosure. Though the supply was exposed to vibration they did not use standoffs between the baseplate and PCB nor between chassis and PCB. A metal shielding cage was screwed only to the PCB. The total weight of the Vicor module was supported by the solder joints of the pins while the baseplate was just glued to the bottom of the box.
The customer mentioned that up to four outputs in parallel are planned for the future. Since VI-J modules are not intended to be paralleled, the Vicor recommendation was that Mini modules be used. The final design used Mini modules attached using standoffs with soldered pins.