You are better off using the highest main output voltage you can tolerate because of the relatively poor coupling of the low and high voltage windings that results in an error in the un-regulated output (In this case the 170V for instance): This error is manifested as a change in the high voltage output with a change in load on the low voltage output as well as the load regulation of the high voltage output itself. The lower the difference between the regulated and unregulated voltages, the better the winding coupling and therefor the better the cross regulation. The high voltage output operates like a peak detector when un-loaded so even a little bit of pre-load (Say 1%) goes a long way to improving the load regulation of the high voltage output.
1. The winding area (Not core area) for the secondary of these transformers is designed to support the output POWER for which the power supplies are rated so there is ALWAYS enough winding area, regardless of the voltage that is output. Few thick wire turns for high current == Many thin wire turns for low current. 2. The Cincon TR1509 is a perfect platform for this modification as the secondary is the outermost winding and the cores are glued in a very easy way with regard to separation. The varnish used in the industry has a relatively low transition temperature: I am using a Saike hot air reflow station set to 425F and I heat the core uniformly until the varnish between the core and bobbin yields with gentle pressure. Avoid applying heat to the entire transformer vs just the cores. 3. What ever the power supply is rated for in watts, that is the power that can be delivered before and after the modification. Note that most power supplies have two current limit mechanisms; Primary side and secondary side. Adding a second winding will still use the primary side limits as the current to deliver a particular power output remains constant but since the currents are much lower at higher output voltages for a given power level, any secondary current sensing will never come into play. However, any secondary over voltage protection will still be active since the regulated output voltage has not changed. The 9V output of the Cincon TR1509 is just right as it gives plenty of headroom for a 5V regulator while maintaining a reasonable primary to secondary turns ratio. It would be possible to feed the high voltage into the feedback network while using the low voltage rail to bias the opto-coupler circuits. This would result in a tightly regulated high voltage output which sloppy low voltage regulation but with sufficient overhead for a 5V regulator the application circuit would not see the variations. Although this goes a bit further than most people are comfortable with, this would have the added benefit of preventing load variation or multiplex scan induced brightness variation in the circuit. I am getting a PWB made that mounts on the HV capacitor to hold the HV diodes and a voltage divider just for this improved scenario. On Thursday, October 15, 2015 at 9:20:24 AM UTC-7, gregebert wrote: > > I'd say it's dependent on : > > 1. How much core-area is available for the additional winding > 2. How easy it is to remove & reinstall the bobbin > 3. The total power of the supply > > If you're going to drive six IN-18's (the largest commonly-available > nixie) at 150VDC, that's about 5 watts. Any power used for the new winding > would need to be offset by using less power from the original output(s). > Otherwise you will be overloading the supply. > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/0a98b253-65b7-4c6e-9ab6-1c7e7fdda4cc%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
