Replies

1. 
   Snort | Jul 09, 2003 04:35am | #1

   I've got a5 hp three phase jointer running off a 10 hp three phase slave/converter, dang thing does take about and hour to stop. Think your super stopper would work?

   EliphIno!

   
1. 
   jhausch | Jul 09, 2003 05:53am | #2

   I do believe it would.

   1) When the motor start button is pushed, the contactor in the Short Stop is set to just act as a "pass through"

   2) When you push the stop button, the Short Stop breaks the power to the motor (just like normal) except it momentarily takes some of the incoming AC and inverts it to make DC, it then "injects" the DC into the windings of the motor to bring it to a stop.

   There are two "one time" adjustments, one for torque and one for time.  You set it up so the torque stops the motor as fast as you want and set the time so you hear the slight "hum" of the breaking action for about one second after the motor comes to a stop.

   My only questions/concerns:  I am assuming that you first spool up your phase converter, then you start your jointer.  Then when you are done, you stop the jointer then shut down power to the converter.  I feel pretty confident telling you that the short stop can live between the converter and the jointer.  I am less confident that the short stop would work (or that it would be a good idea) to use it to stop the phase converter.

   Let me know if you were thinking about using it to stop the converter and I will do some more investigating.

   Thanks for your interest.Steelkilt Lives!

1. 
   junkhound | Jul 09, 2003 06:08am | #3

   6 each 50 cent diodes and a 3PDT switch and the suckers stop in about 1/2 second - look up "dynamic braking" on any search engine. 

   I liked the pix with the spinup motor on that converter - looked like the spinup was from a 1938 Maytag washer??<G>

1. 
   IMERC | Jul 09, 2003 06:14am | #4

   The cord was classic too.

2. 
   caseyr | Jul 09, 2003 08:08am | #5

   Being somewhat posessive of all the digits I now have, I may start saving my pennies for one of these, that is if future tests show that the cabinet saw is a reasonable replacement for my old rockwell unisaw:

   http://www.taunton.com/finehomebuilding/pages/h00117.asp

   I saw a demo of one of the test models, and it is amazing how little damage is done to a hot dog pushed into the blade.

1. 
   jhausch | Jul 09, 2003 11:48pm | #6

   Just for the record:

   Unlike the SawStop, the Short Stop DC injection motor brake is NOT a device designed for personnel safety.   It is designed to get the motor to a stop in a reasonable amount of time so the operator can walk away from the machine with all parts now stopped.  It is not designed to engage if something goes wrong.

   Sort of like an E-stop button.  A big red E-stop is to protect machines, process, and/or machinery, not people.  As a safety advisor once said, "Unless the operator manages to hit the button with his toe as he is dragged into the machine, it ain't gonna do him any good."

   Steelkilt Lives!

2. 
   Snort | Jul 10, 2003 02:19am | #7

   The on off switch may be the sticking point...mine doesn't work.

   I've got a switch for the 110 start up motor, then I've got to throw the breaker in the main panel box, not too far away. I've tried a bunch of in line switches, no go!? EliphIno!