China manufacturer of magnetic ballasts for metal halide flood lights & hps flood lights

The MH ballasts provides the proper starting voltage, operating voltage and current to the lamp to initiate and sustain its arc. High intensity discharge (HID) lamps have negative resistance, which causes them to draw an increasing amount of current; hence, they require a current-limiting device.

Starting the lamp: In MH lamps, ballasts provide the starting voltage and ignition pulses (pulse-start lamps) necessary to ignite the lamp. Probe-start MH ballasts, however, can take as long as 10 to 20 minutes to restrike (re-start) a lamp. Pulse-start MH ballasts can restrike the lamp within 2 to 8 minutes of an interruption in current, because they provide high-voltage pulses to start these lamps.

Regulating lamp current and power: The ballast regulates the lamp operating current flowing through the lamp after the lamp has been started. The ballast is set to deliver relatively stable power to the lamp while regulating the lamp current despite typical line voltage fluctuations. This maximizes lamp life and ensures other performance characteristics such as color and light output.

The ballast provides the following functions:

• It provides starting voltage and, in some cases, ignition pulses. All ballasts must provide some specific minimum voltage to ignite the lamp. In the case of pulse start lamps, an additional high voltage pulse is needed to ionize the gases within the lamp. These pulses are superimposed near the peak starting voltage waveform;
• It regulates the lamp’s current and power. The ballast limits the current through the lamp once it has started. The ballast’s current is set to a level that delivers the proper power to the lamp. In addition, the ballast regulates the lamp’s current through the range of typical line voltage variations, thereby keeping the lamp’s power fairly stable to maximize the lamp’s life and performance and;
• It provides appropriate sustaining voltage and current wave shape to achieve the lamp’s rated life. The hps ballasts provides sufficient voltage to sustain the lamp as it ages.