How can the ballast inductance of high voltage sodium lamp reach the high voltage of several thousand volts?
The voltage is added to the two ends of the high pressure sodium lamp along with the city electricity to cause the gas in the sodium lamp to be broken down and the lamp to be lighted. The process is generally referred to as the ignition stage. When the light is switched on, the equivalent resistance is very small, the lamp pressure is very low, and at this time, the inductance AC impedance in series with the lamp suppresses the lamp current and prevents the current from too large, causing damage to the circuit.
Thereafter, the starter IGN disconnects the B and N terminals and makes the B and LP terminals short circuited. Since the high voltage sodium lamp has not been lighted, it is in the state of shutdown, has no current flow, and because the current on the inductor can not be mutated, the inductance will produce at least a high voltage of over 1000 volts.
Ballast principle as shown above, when the circuit access 220V AC power voltage (usually more than 180V to ensure the effective start, B, N) IGN shorted starter, the voltage is added in almost all ballast L to the charge.
