On Tuesday, April 8, 2014 2:06:50 PM UTC-4, TyngTech wrote: > > Believe it or not, I'm the first guy to install ESC's into one of our > tanks. The landmark Tyng T34-85 T005 to be exact. >
Tovarisch Tyng, Let us recall history correctly. The Dread T34-85 T005 was the first of our tanks to carry a commercial ESC. Hetzer T010 was actually the first to carry an ESC with mixing, linear/exponential speed control and programmable deadband provided by a PIC and eight optically isolated D1D40 SSRs. It was custom-built by gnomes in the silicon foundry at Anvilus Machine Works. That sad, arcane, feature-deprived ESC only worked for ten years before it fried. BTW - Who custom built the first microprocessor relay speed controller for the T34 only one week before the first battle? To offer my two cents - my graduate students and I have used a wide variety of ESCs for research on unmanned ground vehicles (UGVs). Our favorite by far is the Roboteq HDC2450 which is typically too expensive for hobbyists. For smaller cheaper vehicles, my students were enamored with Sabertooth 2x25 and 2x60 ESCs for about a year. However some nasty failures and occasional "twitchy" behavior have led us back to using two Talons with an IMX-1 mixer. Personally, I liked the exponential throttle function on the Sabertooth for my Hetzer because the gun is aimed by skid-steering. However I fried one channel of a 2x60 and went back to Talons/IMX-1 for modular repairability. Kent Massey performed current draw tests on my Hetzer several years ago when he was using it as a military UGV prototype. He measured up to 60A during skid turns in tall thick grass and the Hetzer only weighs about 80 pounds. Consequently, I will be interested to see if Loic's 30A fuses survive in really nasty terrain where Frank's old decrepit Tiger T001 likes to hide. In my opinion, recent discussion about current draw and temperature degradation of FETs in Talons is moot. They are well designed and eminently capable of handling high current and high temperature. Conversely, I believe that the key issue for survivability of an ESC in our hobby is the ability to withstand inductive voltage spikes created by sudden reversal of the motors. My old home-made ESC survived so long because it used an open H-bridge (Coast, not Brake) and had industrial SSRs with significant inductive surge protection needed for industrial actuators. FETs are notoriously susceptible to failure by inductive voltage spikes. It will interesting to see how many of our tankers use the Brake versus Coast function on their Talons, and if we see more failures for one or the other. Joe -- -- You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat+unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat --- You received this message because you are subscribed to the Google Groups "R/C Tank Combat" group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
