Thanks John, Those are all very good tips. I do have a variac and an isolation transformer, but I think I want to get a hold of the tachometer before I start the experiment.
----- Original Message ----- From: "John Kasunich" <[EMAIL PROTECTED]> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Monday, May 07, 2007 10:41 PM Subject: Re: [Emc-users] Turning tiny bits...solution? > For test purposes, a variac with a fuse, followed by an ISOLATION > transformer (120V to 120V) followed by a bridge rectifier and cap, would > work. Start with the variac on zero and slowly increase. > > Doing it without the isolation transformer is EXTREMELY unwise, we'd > like you to stick around for a while. Even with the isolation > transformer, it is very dangerous if you get sloppy. > > You need to establish the required voltage first though, so you don't > wind up over-speeding the motor and wrecking it. > > If you can spin the motor at a known speed using something else (I've > used my drill press for small motors), you can measure the terminal > voltage while it spins. Then you can figure out the volts per 1000 RPM. > Multiply that by 60 to get the volts at 60,000RPM. Then at least > you'll know what voltage you need. > > Example: spin it at 450 RPM, measure 2.35 volts. Then volts/1000RPM is > 2.35/0.450 = 5.22, and volts at 60,000 RPM = 60 * 5.22 = 313V. I doubt > your motor will be that high, I just pulled those numbers out of the air > without working the math first. For the test, you want to spin it as > fast as you reasonably can - 1500 rpm would give a more accurate answer > than 450 rpm. > > The above assumes that this is a simple brush type DC motor. If it is > some brushless thing (which I'd expect at those speeds) then I have no > clue. > > Regards, > > John Kasunich > > ------------------------------------------------------------------------- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
