Patent ID: 6525493
Filing Date: 2003-02-25
Classification: G01N,Y10S

Abstract:
An accelerated weathering apparatus comprising:a specimen chamber configured to hold a specimen; a xenon lamp; a high-instantaneous, low-average current ballast configured to run the xenon lamp to generate a plurality of current pulses which over a full signal have a root mean square (rms) average value of less than &frac15; of the at least 100 amps, where there is a duty cycle of 1:10 or less, said current ballast including: a front end, that produces a high DC voltage, an arc capacitor designed to store energy and release the energy into the xenon lamp as short, high current pulses, a starting transformer which generates a high voltage which facilitates striking an arc in the xenon lamp, a switch located between the arc capacitor and the xenon lamp, wherein when the switch is in an on state, a high current pulse is generated from the energy on the arc capacitor, and is delivered to the xenon lamp, and when the switch is in an off state, current flow is blocked thereby allowing a build-up of the arc capacitor energy, without leakage to the xenon lamp, a dimmer configured to limit the energy being supplied from the arc capacitor, thereby controlling light output of the xenon lamp; an irradiance sensor, which measures the amount of light in the specimen chamber; and an irradiance controller, which receives signals from the irradiance sensor, and adjusts a dimmer in accordance with the received signals, in order to maintain a preselected output from the xenon lamp.