Electronic Ultraviolet Lamp Power Supply Monitors: Lamp Voltage, Current, Power
(Minneapolis, Minnesota - February 6, 2002) Nicollet Technologies Corp. has introduced version Gen 3 of their electronic ballast system (EBS) for powering ultraviolet (UV) lamps which offers the ability to continuously monitor the voltage, current and power drawn by the lamp. Combined with the existing capability of the EBS to provide continuously variable current to a UV lamp based on commands from a computer or programmable logic controller, the new power supply allows manufacturers, food processors and other UV users to fully integrate the production process with the lamp controls to ensure quality, maximize production and reduce costs. For example, a food processor using UV to inspect meat for contamination by fecal matter could detect a malfunction in the UV system by monitoring lamp power and easily locate and re-inspect the affected product.
UV has seen dramatic growth in recent years because it can rapidly cure coatings, inks, adhesives, plastics and composites while virtually eliminating pollution and lower energy consumption. UV is also seeing increasing use in detecting spoilage or contamination in food and disinfecting a wide range of items ranging from water to mail. The new Gen 3 EBS will help promote the proliferation of UV technology by fully integrating the process with the lamp controls in order to closely match the lamp output to the requirements of the applications. As a case in point, a printer could automatically and continuously adjust the intensity of the light to match the ink chemistry. Users can easily determine the relationship between voltage, current and power and lamp output, creating the potential to optimize voltage and current to reduce power costs and maximize lamp life while maintaining sufficient lamp output.
Nicollet Technologies EBS replaces conventional high-voltage capacitor banks and mercury-filled relays with an electronic control that provides continuously variable power over a range of 30% to 100% as opposed to the two or three steps provided by conventional ballasts. Reliability of the EBS measured with military reliability prediction methods is four times higher. The new control is completely factory wired, eliminating labor-intensive wiring of relays and capacitor banks. By profiling current during warm-up, time from ignition to full-power lamp ready can be as short as twenty seconds. Any EBS design can include multiple primaries and secondaries so it can operate multiple lamps or lamps in series.
The EBS consists of a power transformer, inductor, silicon controlled rectifier (SCR) module and a control circuit board mounted on a common base. The power transformer scales input voltage on the primary side to the appropriate lamp voltage on the secondary side and the inductor regulates leakage inductance to help stabilize lamp impedance and limit current. The SCR blocks portions of the line input voltage while allowing other portions to pass in a method known as phase angle modulation to control how much power gets to the lamp. The control circuit measures the actual lamp current, compares it to the setpoint and drives the SCRs with the proper phase angle. This process provides excellent regulation despite variations in temperature, input voltage and lamp conditions, eliminating a typical problem with magnetic ballasts where current depends on a high-voltage capacitor that can have a +20% tolerance.