Just curious. Have you considered throwing a friction device on the flywheel, actuated by a solenoid? That is a proven way to turn rotary motion into heat! A modified bike caliper (disc or shoe type) might do the trick!
--J. Ray Mitchell Jr. [email protected] (818)324-7573 “Truth is treason in the Empire of Lies.” — Ron Paul On Tue, May 21, 2013 at 8:38 AM, Ralph Stirling < [email protected]> wrote: > Our Haas TM-1 mill uses a couple of stovetop heater elements for > the spindle braking resistors. I haven't measured the resistance, > but they sit in a metal cage on top of the control cabinet. I've > never seen them glow. > > -- Ralph > ________________________________________ > From: Peter C. Wallace [[email protected]] > Sent: Tuesday, May 21, 2013 8:17 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Superglue, or Loc-tite for that motors flywheel? > > On Tue, 21 May 2013, Gene Heskett wrote: > > > Date: Tue, 21 May 2013 10:50:27 -0400 > > From: Gene Heskett <[email protected]> > > Reply-To: "Enhanced Machine Controller (EMC)" > > <[email protected]> > > To: [email protected] > > Subject: Re: [Emc-users] Superglue, or Loc-tite for that motors flywheel? > > > > On Tuesday 21 May 2013 10:26:05 Peter C. Wallace did opine: > > > >> When using bipolar transistors as high power current sinks, make sure > >> you are not violating their secondary breakdown specs (a lot easier to > >> kill than you might think) > >> > >> > >> Peter Wallace > >> Mesa Electronics > > > > Despite my confidence that I knew what I was doing, it turns out that the > > SOA ratings on the bugs I bought and which arrived while I was trying to > > get some sleep on a dairy farm in NYS, turns out to suck dead toads > through > > soda straws, Peter. > > > > It appears that the only way I can make a 10 amp sink, would be to make > >15 > > identical circuits and stack them. I'm not all that fond of semi's in > > series. > > > > Page 5 of this link > > > > < > http://www.st.com/web/en/resource/technical/document/datasheet/CD00000005.pdf > > > > > > defines the bad news. Operation in parallel, so they get the full jolt > > from the motor, says I'd have to use an emitter R high enough to keep the > > individual bug under .350 ma. So a 10 amp sink would need 30 of them. > > Sooo, I am back to wondering how much pure R I can find around the place > > that is not already in my EDM lashup. That has a pair of 50 ohm 200 > > watters, and those, even in parallel, won't do much more than slow it at > > about half the rate it was accelerated at by the controller. 10 ohms > would > > be a more serious load. Using the 5 ohm I have from full speed, it could > > exceed 20 amps at the initial contact close an I can see demagnetizing > the > > PM fields. > > > > Do you have any better ideas for a semi choice? These $2.25 each > ignition > > coil switchers sure aren't it. > > > > Thanks Peter. > > > > Cheers, Gene > > > MOSFETS are better but for toughness when you are dissipating KW for > seconds, a big wirewound resistor can't be beat. So I would try your > ignition transistors in switch mode into a say 16 Ohm resistor. > > If you want to get fancy and do constant current (so you get a faster more > linear speed drop instead of exponential), I would use a PIC or something > similar driving a MOSFET in switch mode into a low value brake resistor at > say > 30 KHz and vary the PWM as the voltage drops. > > PS: we blew a couple 75A 1200V Darlintons trying to make a constant > current dynanometer load, so the lesson about secondary breakdown (or > FBSOA) > kinda sticks with me :-) > > > -- > > "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> is up! > > My views > > <http://www.armchairpatriot.com/What%20Has%20America%20Become.shtml> > > If you have to ask how much it is, you can't afford it. > > A pen in the hand of this president is far more > > dangerous than 200 million guns in the hands of > > law-abiding citizens. > > > > > ------------------------------------------------------------------------------ > > Try New Relic Now & We'll Send You this Cool Shirt > > New Relic is the only SaaS-based application performance monitoring > service > > that delivers powerful full stack analytics. Optimize and monitor your > > browser, app, & servers with just a few lines of code. Try New Relic > > and get this awesome Nerd Life shirt! > http://p.sf.net/sfu/newrelic_d2d_may > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > Peter Wallace > Mesa Electronics > > (\__/) > (='.'=) This is Bunny. Copy and paste bunny into your > (")_(") signature to help him gain world domination. > > > > ------------------------------------------------------------------------------ > Try New Relic Now & We'll Send You this Cool Shirt > New Relic is the only SaaS-based application performance monitoring service > that delivers powerful full stack analytics. Optimize and monitor your > browser, app, & servers with just a few lines of code. Try New Relic > and get this awesome Nerd Life shirt! http://p.sf.net/sfu/newrelic_d2d_may > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > > > ------------------------------------------------------------------------------ > Try New Relic Now & We'll Send You this Cool Shirt > New Relic is the only SaaS-based application performance monitoring service > that delivers powerful full stack analytics. Optimize and monitor your > browser, app, & servers with just a few lines of code. Try New Relic > and get this awesome Nerd Life shirt! http://p.sf.net/sfu/newrelic_d2d_may > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Try New Relic Now & We'll Send You this Cool Shirt New Relic is the only SaaS-based application performance monitoring service that delivers powerful full stack analytics. Optimize and monitor your browser, app, & servers with just a few lines of code. Try New Relic and get this awesome Nerd Life shirt! http://p.sf.net/sfu/newrelic_d2d_may _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
