[Repeater-Builder] Re: Astron Power Supply Crowbars
I have read with interest the recent postings on the Astron Power Supplies and Crowbars. Question - has this problem been primarily with the switching power supplies or the transformer based power supplies? We have a Astron RS-20A and a RS-35A that we have been running for a couple of years without problems in a high RF environment. Have the switching power supplies such as the SS-25 and SS-30 from Astron had any known problems? Thanks Steve Hansen --- In Repeater-Builder@yahoogroups.com, skipp025 [EMAIL PROTECTED] wrote: Most of the crowbar problems I've sourced once past the Astron regulator board were traced to weak filter caps of aged units. The crowbar circuit works well. skipp Daron J. Wilson [EMAIL PROTECTED] wrote: Let's not lose sight of the fact that the motor circuits that are generating the spikes should be examined for ways to reduce or eliminate same. Moreover, tinkering with the power supply crowbar circuits is really treating the symptom rather than the problem. I have to disagree. Both of my rack mount 50 amp supplies have done this, on remote sites or in the garage with NO problem on the input side. If you try to draw more than 10-12 amps when you turn them on, it immediately crowbars. The only way to get it to run is to turn it off, drain the caps, remove the load and turn it back on. Then you can attach the load *spark* and it works fine. That is the design flaw that I feel needs to be corrected. 73 N7HQR Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: Astron Power Supply Crowbars
Most of the crowbar problems I've sourced once past the Astron regulator board were traced to weak filter caps of aged units. The crowbar circuit works well. skipp Daron J. Wilson [EMAIL PROTECTED] wrote: Let's not lose sight of the fact that the motor circuits that are generating the spikes should be examined for ways to reduce or eliminate same. Moreover, tinkering with the power supply crowbar circuits is really treating the symptom rather than the problem. I have to disagree. Both of my rack mount 50 amp supplies have done this, on remote sites or in the garage with NO problem on the input side. If you try to draw more than 10-12 amps when you turn them on, it immediately crowbars. The only way to get it to run is to turn it off, drain the caps, remove the load and turn it back on. Then you can attach the load *spark* and it works fine. That is the design flaw that I feel needs to be corrected. 73 N7HQR Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: Astron Power Supply Crowbars
I have never had an RS (linear) Astron power supply go into crowbar mode, but I can see why a healthy spike could cause that to happen. I have RS-7, RS-12, RS-20, and RS-35 units that have been working fine for many years, although all of my new units are SS (switching) supplies. The RS-35M has a typical crowbar circuit, which comprises an SCR across the output, and a simple trigger circuit. The gate of the SCR has a 0.1 uF capacitor, C102, to bypass spikes and prevent (?) false operation. My gut feeling is that this capacitor should be much larger to do its job reliably; I would replace it with a 2.2 uF tantalum capacitor in parallel with a 510 pF silver-mica capacitor. Let's not lose sight of the fact that the motor circuits that are generating the spikes should be examined for ways to reduce or eliminate same. Moreover, tinkering with the power supply crowbar circuits is really treating the symptom rather than the problem. 73, Eric Lemmon WB6FLY Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
