Tuesday, November 16, 2010
NIC Solid State Tesla Coil Project Update 1
Both H-Bridge circuits are now complete, using 500v 20A mosfets (the common IRFP460) mounted on their own heatsink. The other heatsink contains split recovery (600v 30A) diodes and blocking barrier diodes (40v 30A). The purpose of the recovery diodes is to provide a freewheeling path for current when the coils are run outside of their resonant frequency. The blocking barrier diodes prevent reverse current from entering the mosfet bodydiode when the freewheeling diodes are conducting.
You may have noticed the wiring terminal strips near the power plug and main powers witch (bottom left of the conduit box). The power switch and transformer have been fused and wired. the bridge rectifier and voltage doubler circuits will be installed soon. Currently the H-Bridge is just standing in the case and isn't connected to the circuit.
The control panel now has both the main power switch and control board switches installed. Two potentiometers seen to the right are for tuning the drive frequency of the coil and changing the break rate of the interuptor circuit. The control board switches are used to enable/disable the driver board and to change from audio mode to interuptor mode. The control panel is not complete, it will feature a status indicator LED, modulation LED and a blown fuse indicator LED.