I'm disassembling an old 3-phase Inverter cabinet built in late 80's and this cabinet has some of the largest Diodes I've ever seen (A397 HS Rectifiers) and several large SCRs, for the inverter. ALL the heatsinking in this unit is HUGE! The parts are old, but I managed to locate some datasheets.
Since this is not my cabinet.....
I'm taking the parts I find most valuable for my circuits, but need to know many uses for these parts so I don't pass up the opportunity to build some great projects.
Most of these SCR modules and heatsinks are going up for sale, so I can't keep them all, so I'm picking out what is best for DIY. I already made a massive bridge rectifier from the diodes!!! I'm planning on making a COILGUN, so I will use the biggest SCR modules to discharge a capacitor bank into the coil.
Parts:
A397 1500V 400A High Speed Rectifier Diode (I wonder if it's fast enough for SMPS because it's older part)
SCRs-All GE
C385SX228 C385 (400A, 700V)
C358T (225A, 1200V)
C380M (380A, 600V)
C380N (380A, 800V)
Are the (high speed) diodes fast enough to use for SMPS not just 60hz AC?
Other than discharging huge capacitors, what other uses are good for such massive SCR?
Since this is not my cabinet.....
I'm taking the parts I find most valuable for my circuits, but need to know many uses for these parts so I don't pass up the opportunity to build some great projects.
Most of these SCR modules and heatsinks are going up for sale, so I can't keep them all, so I'm picking out what is best for DIY. I already made a massive bridge rectifier from the diodes!!! I'm planning on making a COILGUN, so I will use the biggest SCR modules to discharge a capacitor bank into the coil.
Parts:
A397 1500V 400A High Speed Rectifier Diode (I wonder if it's fast enough for SMPS because it's older part)
SCRs-All GE
C385SX228 C385 (400A, 700V)
C358T (225A, 1200V)
C380M (380A, 600V)
C380N (380A, 800V)
Are the (high speed) diodes fast enough to use for SMPS not just 60hz AC?
Other than discharging huge capacitors, what other uses are good for such massive SCR?
Phase control for a spot welder a 300 - 400 amp device will do a small spotwelder.
With the scrs, they need to be driven hard to ensure fast turn on, as long as you stay within their dI/dt rating they will discharge capacitors all day. I think you will need a diode or two to prevent the capacitor bank being charged in reverse by the energy remaining in the coilgun inductance.
As scrs go they are not that large, check out a site like westcode semiconductor to see what is available.
With the scrs, they need to be driven hard to ensure fast turn on, as long as you stay within their dI/dt rating they will discharge capacitors all day. I think you will need a diode or two to prevent the capacitor bank being charged in reverse by the energy remaining in the coilgun inductance.
As scrs go they are not that large, check out a site like westcode semiconductor to see what is available.
Thanks. I'll be using a couple to build the "Control" for the welder to chop the sine wave to limit the current.
I have 12 X 3300uf, 350VDC for the bank, (39600uf) connected to each other by copper bars for my coilgun. I figure I will run a pair of thick wires to the coilgun from the bank + circuitry. I'll use one (or two) of the big 400A SCR to dump the current, and one of the big diodes to catch the reverse kickback pulse.
Are these types of "high speed" DIODES, able to be used for SMPS? The datasheet shows switching curves up to 20khz, but I wonder if I can drive them at 40-50khz but at reduced power?
2.4kJ you will need to be careful to use enough inductance in you coilgun. Anyway you can calculate the projectile residence time in the barrel, peak field should probably occur 2/3 of the way down the barrel making the LC period roughly 3x the projectile residence time. Tie the bus wires together with closely spaced cable ties, they need to be close to reduce stray inductance but they will want to fly apart due to the magnetic field from the current flowing in the wires.
I would not recommend running large devices at 40 kHz, industrial scale SMPS usually use lower frequencies to reduce switching losses in the naturally slower large devices, 400Hz to 10 kHz is typical. Stray inductance and skin effect will be significant if you try to hard switch hundreds of amps at 40+ kHz
I would not recommend running large devices at 40 kHz, industrial scale SMPS usually use lower frequencies to reduce switching losses in the naturally slower large devices, 400Hz to 10 kHz is typical. Stray inductance and skin effect will be significant if you try to hard switch hundreds of amps at 40+ kHz
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