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Posted By Schlosser on 02/27/2008 2:39 PM
Had to learn this stuff back when the Navy got me in 1945, jimtyp; I think it's easier to learn when you're young. Neither batteries or large capacitors come in 'AC', so backing up presents an additional problem. This can be solved by rectifiers but the hazards of exploding capacitors - or batteries - are really not good.
While working for IBM back in the 50's, I had the end covers off a big power supply, larger that a side-by-side freezer/refrigerator, when one in a bunch of capacitors blew. Fortunately, the plastic shield held; I just aged a few months. These 'safety-covers' had just been recently installed as several employees had been injured by exploding caps.
Art
First mainframe computer I worked on had several 48V 5000 uF electrolytic capacitors in it (6" long, 3" diameter). One of the first test steps was to get on a ladder to physically look at them to verify they were installed correctly (little molded in "+" sign on the "right" bus bar).
Measuring them with a VOM was iffy at best. Sometimes you just could not tell which pole was the positive, especially because there were so many in parallel on the power bus bars
One day. Day shift claimed to have verified a new computer chassis and yet one "blew" when they applied power. The guy was in big trouble for allegedly "not checking".
When I came in for Night shift I was admonished THREE times (my Shift Foreman, the Department Supervisor and THE Corporate Director of Safety) to be sure I checked them. I DID, under the supervision of the foreman, even! BUT... Mine sounded like a cherry bomb in a trashcan when it went! Blew brown/black sticky foil and paper all over the place! I pulled a dozen caps from stock and found the manufacturer had assembled about 1/2 of them with the end plate 180-deg out, which could not have been easy since the connections inside were not symmetrical.
As to the question here. A cap could hold power for a sound card or a low current lamp for very minor power interruptions, but not a power hog like a motor. This would require a high current capacity battery and if you are going that far, get rid of the track power and just run from the battery. Or go Live Steam and forget electricity all together!
Had to learn this stuff back when the Navy got me in 1945, jimtyp; I think it's easier to learn when you're young. Neither batteries or large capacitors come in 'AC', so backing up presents an additional problem. This can be solved by rectifiers but the hazards of exploding capacitors - or batteries - are really not good.
While working for IBM back in the 50's, I had the end covers off a big power supply, larger that a side-by-side freezer/refrigerator, when one in a bunch of capacitors blew. Fortunately, the plastic shield held; I just aged a few months. These 'safety-covers' had just been recently installed as several employees had been injured by exploding caps.
Art
First mainframe computer I worked on had several 48V 5000 uF electrolytic capacitors in it (6" long, 3" diameter). One of the first test steps was to get on a ladder to physically look at them to verify they were installed correctly (little molded in "+" sign on the "right" bus bar).
Measuring them with a VOM was iffy at best. Sometimes you just could not tell which pole was the positive, especially because there were so many in parallel on the power bus bars
One day. Day shift claimed to have verified a new computer chassis and yet one "blew" when they applied power. The guy was in big trouble for allegedly "not checking".
When I came in for Night shift I was admonished THREE times (my Shift Foreman, the Department Supervisor and THE Corporate Director of Safety) to be sure I checked them. I DID, under the supervision of the foreman, even! BUT... Mine sounded like a cherry bomb in a trashcan when it went! Blew brown/black sticky foil and paper all over the place! I pulled a dozen caps from stock and found the manufacturer had assembled about 1/2 of them with the end plate 180-deg out, which could not have been easy since the connections inside were not symmetrical.
As to the question here. A cap could hold power for a sound card or a low current lamp for very minor power interruptions, but not a power hog like a motor. This would require a high current capacity battery and if you are going that far, get rid of the track power and just run from the battery. Or go Live Steam and forget electricity all together!
