Power Supply Protection - Inrush (very nerdy)
Adequate protection means a two-step process. Limitation ramping of AC inrush current in conjunction with a delay-on-make DC relay load isolator. Starts off with load isolation, when softened inrush i...
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Yup. And thermistors get tired and they are "difficult" to select for profiling the inrush. Not only does softening the current peak help borderline charging sources (generators) but shocking large electrolytic capacitors is bad juju for them getting gray hair prematurely.
I would love to see a full five seconds elapse for capacitors to charge then engage the output. Wouldn't it be nice to ramp the output as well? That is beyond my pay grade. Ramping the voltage divider 10-turn pot would be the way to do it but end resistance would have to be precision controlled and dead-on repeatable.
When I engage my massive 400+ lb ferroresonant charger* it actually bangs hard enough to feel it in my feet. I was fortunate enough in 1987 to bid on a partial box of 480uf 1240vdc capacitors (17). The first set lasted 24 years and a week before the NYC attack I found my trusted #13 transformer tap had shifted almost .40 volts higher. The caps were dying. Curious? How big are these puppies? Roughly the size of a 64 oz can of tomato juice only about three inches taller. Manufactured by "Linol" in Illinois. I am afraid to start pricing a soft start and delay contactor setup for the Big Belden. The 180 ampere ATS was bad enough.
*The charger is as big as an old timey Wells Fargo safe. It has a 3' tall full width hinged door. I got cute and installed a 30 watt LED lamp and "inside" voltage and amp meters. A massive 10-watt 3000 ohm 5-turn Ohmite pot (also NASA) controls an H1 and H2 tickler transformer. An 80 watt 240vac ball bearing squirrel cage fan blasts the inside with "cooler" air.
Setting the generator, and chargers and wiring everything, took 3-months of 7-day workweeks. Jesus and crew helped under supervision. They had to have days off. I worked like a dawg.
The power supply soft-start is a hobby make-work exercise. But a time is coming when I will not be around, and I want to leave the kids set up with stuff that will endure.
Beats vegetating in front of the boob-tube.
I would love to see a full five seconds elapse for capacitors to charge then engage the output. Wouldn't it be nice to ramp the output as well? That is beyond my pay grade. Ramping the voltage divider 10-turn pot would be the way to do it but end resistance would have to be precision controlled and dead-on repeatable.
When I engage my massive 400+ lb ferroresonant charger* it actually bangs hard enough to feel it in my feet. I was fortunate enough in 1987 to bid on a partial box of 480uf 1240vdc capacitors (17). The first set lasted 24 years and a week before the NYC attack I found my trusted #13 transformer tap had shifted almost .40 volts higher. The caps were dying. Curious? How big are these puppies? Roughly the size of a 64 oz can of tomato juice only about three inches taller. Manufactured by "Linol" in Illinois. I am afraid to start pricing a soft start and delay contactor setup for the Big Belden. The 180 ampere ATS was bad enough.
*The charger is as big as an old timey Wells Fargo safe. It has a 3' tall full width hinged door. I got cute and installed a 30 watt LED lamp and "inside" voltage and amp meters. A massive 10-watt 3000 ohm 5-turn Ohmite pot (also NASA) controls an H1 and H2 tickler transformer. An 80 watt 240vac ball bearing squirrel cage fan blasts the inside with "cooler" air.
Setting the generator, and chargers and wiring everything, took 3-months of 7-day workweeks. Jesus and crew helped under supervision. They had to have days off. I worked like a dawg.
The power supply soft-start is a hobby make-work exercise. But a time is coming when I will not be around, and I want to leave the kids set up with stuff that will endure.
Beats vegetating in front of the boob-tube.
