Corby, Assuming that what you want to do is find a substitute for the F1152, you should be aware that schematics don't give you enough information to build one from scratch. The easiest thing to do is buy one from a catalog of DC-DC converters with the appropriate voltages and power - unless the frequency matters. Modern converters run at 100 KHz or more.
Assuming you have the converter but it doesn't work, if the windings aren't burned or shorted and the core isn't cracked, the transformer should be OK. If a winding is bad, it shouldn't be difficult to rewind for a 20 KHz converter. There's a lot more turns at 60 Hz. You must use the same wire size or the winding won't fit. But if you have to get into the magnetics, as I did for 30 KVA frequency changers in 1968, and also DC converters, here are a few design considerations: (This assumes a saturating core oscillator with little more than two semiconductor switches for the oscillator and a bridge rectifier and filter for the output.) 1. Cores have maximum operating frequencies depending on material; power capacity depending on amount of core material; and a primary winding depending on the input current and voltage, or voltage and power. 4. The core has an open area which will be filled with windings. The size/gauge of the wire depends on the current carried. The number of turns determines the inductance of the primary, which determines the time that it will take for the core to saturate at a fixed supply voltage, by V = L di/dt. The saturation time, times 2, is the period of the oscillation. Note that i is not a function of output power, but is determined by L and V. For a given L and V, the saturation time is determined by the amount of core material. The current falls out of the equations when you are looking for saturation time. To be precise, the current discussed here is the magnetizing current. Total current increases as the output draws current. 8. The open area in the core also has to accommodate the secondary. The number of turns is determined by the input/output voltage ratio. The wire size for the necessary current and the open core area determine the number of turns that will fit, as does the thickness of the insulation. Throw in the calculations required to minimize the weight for a given power, and perhaps you begin to see why transformer design is as much art as science. Disclaimer: This is from memory, as my design books have been downsized on the way to a senior living apartment. Bill Hawkins -----Original Message----- From: [email protected] Sent: Friday, August 29, 2014 5:12 PM I'm trying to built a DC to DC from an existing schematic for a frequency standard I'm working on. The transformer core is identified as an Indiana General F1152-1-6 The Dc to Dc is running at 22Khz and maybe 20 Watts. Can't find any info that would allow me to decide on a proper substitute. Anybody out there have any data on this? Thanks. Corby _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
