wire speed too fast

admin

i'm having a problem with my wire feed being too fast even on the lowest setting. it's really annoying i've been working around it by having the voltage a little higher than i want it.i know there's a trim screw on the circuit board but i believe i have it turned clockwise as far as it can go. and it's still too fast. what can i do?it's a Century 170gs i can get more info if needed. thanks Josh
Reply:Thats a tough one.  Did you try turning the pot counter clockwise?  cc weld it like you own it
Reply:yeah i just went out and double checked if i turn it all the way counter clockwise it's much faster on the lowest wire speed on the knob. if i turn it all the way clock wise it's pretty slow but not slow enough for what i need to do. i want it to be like crawling out at 0 on the wire speed. at the lowest wire speed  i can't go below 5 on the voltage. so i deffinately think i've found the trim setting but it doesn't change it enough .
Reply:I had the same problem, I had to change the resistor values on the control PCB. There is a square wave generator that runs at 60Hz/sec, the wire speed control changes the On-Off time without changing the frequency. The square wave is feed into an integrator that controls the voltage to the wire motor. Short pulse time = slow, long = fast. You will need a scope to see the effects.
Reply:yea i read something about that i think in the post you were in but it's so far over my head i don't know what you're talking about with the o scope and all that . should i just get a new welder or try to do this? i'm pretty smart i can figure most things out just not experienced with what all that means
Reply:That’s my point Jeff, you need to be a Grand Wizard of the First Order to take the problem on.
Reply:What the french, toast.
Reply:so what equipment would i need to buy to do that.?
Reply:ok well i guess i just need to know how to change the resistor values on the pcb. literally how do you do that? what is involved ( in steps )?
Reply:there's got to be some way to jerry rig it right? so is this welder trash or what?
Reply:haha that's what i was thinking. hey anyone know what sort of establishment would be able to fix something like this?
Reply:Maybe put a resistor in the wire going to the feed motor to reduce the voltage and slow it down?MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:ok that sounds easy enough, would i find one at radio shack or what? what spec resistor?
Reply:Yes rat shack should have resistors.  You'll probly have to buy a few of them and experiment untill you find one you like.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Can you use smaller wire?Real world weldin.  When I grow up I want to be a tig weldor.
Reply:ok i'm going to try to get some resistors at radio shack today since i don't have work for a week or so and i want to get this project done that i started hehe. dan r - do you mean smaller welding wire or wire feeding the motor power??
Reply:alright well i put a resistor on the motor and it "fixed" it. i tried 1 ohm and 10 ohm and decided on 10.  below 5 on the knob  it doesnt move but i can get it to creep out now. i can actually use the welder on lower voltages now. and stop the popping i'm experiencing. thanks so much for the idea
Reply:You need to be cautious with the resistor fix.  If you put a resistor in there that is under-rated powerwise, it could literally burst into flames.  David R's suggestion seems most logical to me.  What size wire are you using?Tim
Reply:I don't seem to have an "edit" button.  I guess I haven't been here long enough...Anyway, a quick and dirty way to test to see if your resistor is underrated for power is to hold your finger on it.  If it gets too hot for you to keep your finger on it for, say, 10-15 seconds, it probably is too small for the job.  Be sure to test at min and max speed settings.  Also be sure you don't electrocute yourself if there's high voltage present.Edit:  Sheesh--NOW there's an edit button!  I must be losing my mind.Tim
Reply:Originally Posted by timrbI don't seem to have an "edit" button.  I guess I haven't been here long enough...Anyway, a quick and dirty way to test to see if your resistor is underrated for power is to hold your finger on it.  If it gets too hot for you to keep your finger on it for, say, 10-15 seconds, it probably is too small for the job.  Be sure to test at min and max speed settings.  Also be sure you don't electrocute yourself if there's high voltage present.Edit:  Sheesh--NOW there's an edit button!  I must be losing my mind.Tim
Reply:well i only know the basics about electricity and the good part is it works. the resistor is rated 10 watt i believe it's like a big block. i know it's not the safest but i don't know what other options i have i need to get this project done and then i can get a new welder.i'd go check the wire size but the box is closed up and i don't feel like it. how much would lowering the wire a size or 2 really change it?
Reply:A smaller diameter welding wire will need to feed faster for the same weld, so that may work good for your too fast feeding situation if the resistor is not working well for you.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:oh ok i'll try that too. the resistor is working it gets hot on a long bead . i'm using .35 if i step down to .30 how much of a difference will it make
Reply:Originally Posted by JeffreyColeoh ok i'll try that too. the resistor is working it gets hot on a long bead . i'm using .35 if i step down to .30 how much of a difference will it make
Reply:There's not much of a speed difference between .030 and .035.  You can try .023 solid wire for more feed speed required.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith opwell i'll just get a 2lb roll and give it a shot. can i run .030 with a 35 tip? how about 23? or will i need to change the liner and tip? sorry i'm still learning whats acceptable and all that.
Reply:.045" wire draws one amp for each inch per minute.    150 Ipm = 150 amps..035 wire draws one amp for 1.6" per minute      150 * 1.6 = 150 amps  or 240 ipm.030 draws one amp for every 2 ipm.                 150*2 = 150 amps or 300 ipm.025 drews one amp for every 5 ipm.                 150*5 = 150 amps or   750 ipm.Make sense?This is why I like.045 wire.    As wire speed picks up, there is a curve and the amps don't increase as fast.  More prominent in the smaller wires.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:alright well i got a .030 tip and a 2lb of .030 and tried without the resistor out and the trim all the way down . it works really well at the voltages the wire is rated for . i think my problem was that with 35 i cant really do the material i was trying to ( 1/8 " ) so stepping down the wire size really helped out. the welder is an old pos and i'm getting some decent welds with it now. some day i want to step up to something newer but i got this one for such a steal. i can tell no one really ever used it.
Reply:Glad  you got it worked out!MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:DavidR,Esab's web site shows the following graph that shows how wire feed speed effects welding currents for different wire sizes.  It seems to show that smaller wire sizes have less amperage change than larger wire sizes as wire feed speed increases.According to this graph (if I'm reading it correctly) a larger wire size will have greater amperage increases with smaller changes in wire feed speed.Is this what you were saying? Attached Images
Reply:I can understand why you have trouble with 0.035 wire at low speeds. The century 170 model 117-079 can easily handle 0.035 wire at higher wire speeds for thicker stock, it’s rated at 130 A, 30% duty cycle, max 170 A & 5/16”.
Reply:Yep, you got it. Originally Posted by joedirt1966DavidR,Esab's web site shows the following graph that shows how wire feed speed effects welding currents for different wire sizes.  It seems to show that smaller wire sizes have less amperage change than larger wire sizes as wire feed speed increases.According to this graph (if I'm reading it correctly) a larger wire size will have greater amperage increases with smaller changes in wire feed speed.Is this what you were saying?