VS - Lighting Systems - Lighting - 998542

4. Run-up This is the key stage of the start-up process. In order to meet the R99 regulation, the start transient power during the run-up is higher than the expected steady state level; the ballast then controls the lamp power to ramp down to the normal level. 5. Steady state In steady state, all metal crystals are vaporised and the arc has attained its stable shape, meaning the luminous efficiency has reached its nominal value. The ballast is now supplying stable electrical power so the arc will not flicker. Stable operating voltage is 85 volts AC in D1 and D2 systems, 42 volts AC in mercury-free D3 and D4 systems. The frequency of the square-wave alternating current is typically 400 hertz or higher.

After ignition and take-over, the operating frequency is switched to 20 Hz for the warm up stage.

Phase 2

Heating Salts evaporation Maximum intensity (I)

Phase 3

3. Warm-up In this stage, the DC/DC (direct current) converter provides a certain amount of current, depending on the lamp condition to sustain the arc. The converter works as current mode, and generates a square wave AC current (alternating current). As the frequency is low (20 Hz) when compared to the steady state frequency, it’s also called DC status.

Light emission 3200 lumens - 35 W

When the warm-up stage is over, the inverter operates at 200 Hz.

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