James S;

Thanks for the reply regarding the Schematic(s)!

Below is some information per your questions:

1:
with reference to the high pressure sodium constant wattage autotransformers, how does the ignitor work?

The Ignitor is a string of "Tank Circuits" - composed of Capacitor / Resistor / Diode elements, which create a pulse of current being pushed by a high voltage.
The Tank Circuit used with the Ignitor is similar to the Tank Circuit used for firing the flash lamp on Portable Cameras (builds a voltage of >90V from the ±3V power from the "AA" Drycells).

2:
Does it stop and start the supply to make the reactor section produce high voltages to strike the sodium?

Actually it works as a "Stand-Alone" component, which is current limited by the Reactor, and has its own tapped lead from the Reactor.
During all operations - starting thru normal operation, the Reactor works as normal.
Ignitor will operate during "High Impedance" situations with the lamp (AKA no arc time, along with missing lamp).
Once the lamp has established an arc, the Impedance becomes low, which results in the bulk amount of current flowing thru the lamp, instead of thru the Ignitor.

3:
if so why does inductive reactance not oppose the rapid change in voltage?

Inductive Reactance occurs with a changing current, and side effects are a counter EMF pushing an inductive current backflow (in very basic terms!).
The Reactor's main function is to "React" against a level of current flowing thru the complete circuit (lamp + ballast), so the lamp does not destroy its self from excessive current draw.

4:
Also which coil limits the current once the lamp is illuminated?

The Reactor section / coil does the current limiting throughout the operation - from startup to normal operation.

5:
And finally what kind of voltage are we looking at on the link between the auto and reactor coils?

For Medium based HPS lamps, the voltage will be a nominal 55 volts at the Reactor's output to the lamp. Nominal being the target operating voltage. It will raise and lower depending on the lamp's state of operation.
The voltage between the autotransformer and the reactor input for the same lamps will be 100-120 volts.
For Mogul based HPS lamps, the reactor output nominal voltage will be around 100 volts, with apx. 180-210 volts between the autotransformer's output and the reactor's input.
Pulse ignitor's output is around 1500 volts nominal - depending on the lamp's age and condition, along with the arc tube's temperature.

6:
also to agree with the guys in this section (on another topic) your doing a great job

Thank you for the kind words! Glad to be of help!

7:
I too have learned a lot more since using the forum and enjoy being able to ask others with more experience and knowledge

That's what we're all here for!!! Once again, glad to be apart of this!

8:
cheers mate

See 'ya later, Gator [Linked Image]

Scott35

p.s. edited some baad spel-ling, but probably not all of it!

[This message has been edited by Scott35 (edited 11-10-2003).]

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!