On Friday, June 15, 2012 12:40:27 AM jeremy youngs did opine: > hello again gentlemen, I broke down and bought a kit for my steppers and > it should arrive tomorrow, great!!!!!! 2 yrs of waitng and this thing > is finally coming together. I am currently running a 2.5 hp treadmill > motor with the original driver. the driver gets pretty warm after 15 > min or so and goes to thermal shutdown. Im wondering does lcnc output > a 0-5 v or can it generate a pwm waveform directly? if it will generate > pwm than it would be pretty easy to opto isolate and drive an igbt h > bridge for a driver. Any thoughts or suggestions would be greatly > appreciated thank you
Generally speaking, the igbt stuff I have observed has a noticeably slower turnon/turnoff times, which when coupled with their quite a bit higher "on" resistance, does lead to heat problems. So much of the current limiting motor driver market has switched to hexfets, which with the proper drive, can very easily be 10-50x faster in its switching on/off, and when in the on state, have very low i2R losses as they can be driven to be on with an equivalent voltage drop of 10 milli-ohms, or 20 millivolts of loss across the device when it is passing 20 amps. Because getting them turned on that solidly takes a higher supply voltage, there is generally a minimum recommended supply voltage as they will run hotter, a lot hotter for voltages well below the max rating. Using the 2M542 driver, I have quite a few of them, with 4 of them running at 28 volts, rated for 50 volts. They run noticeably warmer than another pair running on about 39 volts, and one of them is running at its full 4.2 amps. Most of the heat in that box actually comes from the power transformer, not the drivers. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> Don't relax! It's only your tension that's holding you together. ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
