Increasing wire speed.

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I realize there's just a motor that feeds the wire. My question is, Is the "general" speed of the motor control just by increasing voltage. In other words, and generally speaking, with most motors 24v, are these motors an "off the shelf item", is the gear ratio changable, are they basically the same size (for a given size unit), or what???? Is is all done with roller size???Thanks,PeteLast edited by fps; 02-28-2016 at 06:12 PM.Reason: Supper breakEverlast  i210 with 200a spool gunEverlast i140eLOTOS LTP5000D Non-Touch Pilot Arc "Things are never so bad that they can't get worse...."
Reply:The motor and gearing to drive the wire usually adjusts to far faster and far slower than you would ever need.
Reply:I have heard about really old Hobarts that came with two different versions of speeds by changing gears in the gearbox but that was almost 40 years ago.  As mentioned normal range of speeds covers what is required.  On normal constant voltage power sources the speed is constant while you are welding.  The power source regulates the voltage to what you have set it to.  Since the voltage is constant if you want more heat or amperage you simply increase the motor speed.  The power source has to keep the same voltage setting (arc gap) so to increase the burn off rate of the wire the amperage goes up.   There are wire feed motors meant for constant current power sources and they have a motor control that speeds up and slows down to maintain the arc gap (voltage) while the amperage stays constant.  Sensing voltage and speeding the motor up and slowing down makes things complicated.  I actually saw such motor controls on submerged arc welders in the mid 1960's.  The control was run with radio tubes.  I was a teenage in the supervisors office and operators would come in with a bad tube which I would exchange for them.  It was trial and error until they found the bad tube.  The transistor and transformer-rectifiers changed everything.
Reply:Originally Posted by fpsI realize there's just a motor that feeds the wire. My question is, Is the "general" speed of the motor control just by increasing voltage. In other words, and generally speaking, with most motors 24v, are these motors an "off the shelf item", is the gear ratio changable, are they basically the same size (for a given size unit), or what???? Is is all done with roller size???Thanks,Pete
Reply:Nah...keep it simple....because it is simple.Modern all in one mig welders employ basically two controls. One is voltage, the other current....both will remain wherever you set them...Well, except for the "failed to launch" Miller AutoSet, they will....But even in the Miller Autoset the welder selects wire speed based on what voltage you dialed in, but once again it remains at that speed no matter what...With the Autoset stuff, wire speed will only change when you crank the voltage knobbie.The voltage (some call it the heat adjustment) determines simply voltage. The wire speed knob indirectly determines amps, but does it well nuff.You will often see mig machines with click type voltage knobs that simply select different taps off the machine transformer where as you click it upwards, the voltage increases...And in ALL machines, as the voltage increases, so must the wire speed to match the increasing ability to bridge the gap needed to burn off wire....and it is ONLY in that way(the wire speed) that you can actually adjust amps.So NO, the wire speed motor, altho a variable speed motor, is not automatically able to adjust it's speed to maintain required amps....On the MOST machines, you have to dial it in yourself....There are some industrial migs that monitor and automatically adjust both voltage and wire speeds, but you ain't going to be able to affoard one nor would you need to.Keep it simple...Crank in the voltage based on thickness and leave it there, then tweek wire speed as required...It's very important to listen for the weld to properly "sizzle" to know when wire speed is correct....When you do get that perfect sizzle sound, it don't mean nothing except you have wire speed dialed in correctly for voltage....It will not give you decent weld unless you first select proper voltage and control process weld speed with you very hands.