Legend NT no 60Hz generator output.

[fireslayer]

Hello, new here and need some help on Miller Legend NT welder/generator Ser. # KJ068685. Unit had starting problem and idle/run speed problems which have been repaired. There were 2 connectors that were broken in the main start/run switch connector which I replaced. The battery is now new also. Part of the connections kept losing connection at the firewall connector, so I replaced them all and this took care of all the run and idle speed functions. Engine has been serviced and tuned with all new filters, oil and spark plugs. Engine starts and runs very well at correct speeds. Unit appears to weld good and 100Hz outlet has power and operates my disc grinder just fine. I do not have much voltage (one half volt or less on any of the 60Hz outlets. All circuit breakers have continuity and all switches are set in the correct positions, idle lock, idle run etc. The slip rings and brushes have been cleaned and appear to have good contact. I have tried to trace out the winding circuits and I find around 100 volts ac on the junction block below the relays, but it doesn't appear that the voltage is getting back over to the outlets. I sure could use some help troubleshooting this thing. There is a Miller dealer in town, but it's kind of a side thing to them and they seem to be more about the electric units than the gas powered units, and they didn't seem to know how to get an in depth tech manual for the units. I found the owners manual and checked the fuse and all that was in the troubleshooting section. I work on a lot of portable generators in my shop and have a decent understanding of electrical principles. I really could use some unit specific troubleshooting info to get the generator part up to speed. I figure it may be a relay or diode but would like to troubleshoot it correctly. I've dug around on here a little and there is great info and help here. I just haven't found any specific info to this unit yet. If it's here or someone can point me in the right direction I would be most appreciative.

[cruizer]

OK, so you hit the lock out switch, CR1 comes on, deactivating the throttle pick up, CR2 and CR3 then comes on allowing power to flow to the auxillary terminals. via the voltage regulator. and the local voltage control

[fireslayer]

Thanks for your help cruizer. I start the unit up, main switch is in the idle/run position and the unit will run at weld rpms for a short while regardless of which way the idle lock switch is flipped. Once it idles down,(and it always does) it will stay at idle rpms regardless of which way the idle lock switch is flipped. Excuse my ignorance, but how can I tell when the relays come on? I have tried to feel for a click but I'm not sure it could be felt with the vibration of the machine running. I haven't noticed any arc inside of the cr2 or cr3 relays either and I don't know if I should be able to or not. Should the idle lock pull the unit back to idle when the main switch is up in the RUN position also, or does it just function in the idle/run position. The schematic I printed out of the operator's manual seems to leave a lot of the circuits out or something. It appears there's a lot of the wiring and even the idle lock switch isn't shown that I can find anyways. Thanks again for your help.

[cruizer]

CR1 is not comming on when you flip the switch to idle lock, therefore CR2 & 3 are not activating. Trance this circuit out first....

[duaneb55]

The Legend idle system works just the opposite of the typical Miller arrangement in that the throttle solenoid energizes for weld speed and de-energizes for low idle (power) speed.

The IDLE LOCK switch serves two functions in the lock ON position.
1) It shorts the output leads of the weld/100Hz outlet load sensing CT1 (Current Transformer) to prevent the idler control board from energizing control relay CR1.
2) It opens the 12V+ supply circuit to CR3 so it does not energize to close the field voltage rheostat by-pass circuit (thus requiring the rheostat to be manually set to 100 to achieve full wattage capacity of auxiliary power output with idle lock ON).

CR2 energizes at POWER speed (regardless of position of the IDLE LOCK switch) to connect auxiliary power output to the circuit breakers and on to the outlets. As such, you will need to check to visually see if CR2 is energizing at low idle POWER speed to complete the auxiliary power circuits - again, regardless of position of the IDLE LOCK switch.

[fireslayer]

Thanks duane55. Seems to be some conflict on info here, but I think we can get it figured out. Seems Cruizer says that CR1 should energize when the IDLE Lock switch is on, but you say it prevents it from energizing. I know there are 4 wires on the IDLE LOCK switch so I assumed it had 2 different functions.I also did have the FINE rheostat set to 100% as in the directions when testing for 60 Hz auxiliary output. How can I visually tell if CR2 is energizing? Should I see an arc inside of it and what do I need to do to activate it off and on for verification? Also, is there a more complete schematic available besides the one in the owners manual as it doesn't seem to have all the circuits and components on it? Thanks again fellas.

[duaneb55]

cruizer described the more common Miller idler circuit that energizes the throttle solenoid to bring the unit to low idle rather than the Legend's that energizes to increase to weld speed.

I'd post up the Circuit Diagram 184 759-A for your unit that shows what I've described but it's too large to upload.

PM me an email address and I'll send it to you and you can see for yourself.


CR2 should energize 10-15 seconds after any weld load is removed and the unit returns to low idle/power speed. If the relay cover is clear enough to see thru, you should be able to see the relay contacts change state when/if it energizes properly. CR2 de-energizes at weld speed to disconnect auxiliary power output from the outlets because of the excessive frequency at that speed. You could also disconnect the contact leads and check for continuity when/if the relay energizes as it should.

[duaneb55]

email sent.

[welderman2020]

Hey there folks I'm in a desperate situation someone stole my top and side covers and pulled every wire out of my machine my machine is my bread and butter for my family as a mobile welder, I've tried searching all through miller's website and all over Google and all over YouTube, I can't find squat for my machine all bobcat and trailblazers and big 40 and Lincoln electric machines like the sa200..

I have a miller legend nt 5000 watt generator

serial number is kj224613
Model number 903528

I believe I have the correct diagram to wire the machine by looking at the miller legend AEAD 200 MODEL looks to be the same everything looks like it matches up I cannot find a pinout diagram for the relays
Cr1,cr2,cr3 I'm rewiring the machine back to manufacturer last person had 2 extra toggle switches and 4 extra relays, I had no power output and changed the rehostat and couldn't find a rectifier locally and couldn't wait online the original was a 40 amp 800v I installed a 50amp 1000 volt transformer with the 2 green and 1 yellow wire was changed out was a 40 volt center tap I belive got changed to a 30 volt centertap don't know if that makes a difference also was missing a fuse so I stuck a 250v fuse also omed the wires with a toner for the coils I have no short anywhere there also cleaned where the rotar and stator is cleaned the slip rings up that's right at 34 and 28 ohms also replaced the brushes the copper wire inside the spring is kinda just barely touching that springs, please if anyone has the technical shop manual that has the pinout for the relays I would greatly appreciate it alot, I hope it's as straight forward as example wire 50 to cr1 pin 5. I've been working on this machine day in and day out for 4 days trying to get this wiring done but evertime I run into a issues I can't find no diagram also the idle lock switch eaither doesn't work or isn't hooked up no remote control installed on machine. I went to a local shop and they told me miller only used the white wires that are numbered and all the extra wires and relays just get rid of them and I had them check the rotar as well, I can't afford to go to a shop for 2k bucks so I'm doing it myself and got a headache.

If someone has any diagram for the wiring or relays please email them to [email protected]
I need this machine back by yesterday I have a huge job coming up in a week or so.

[Aeronca41]

Tough situation! The two screenshots you posted are from the technical (service) manual; those manuals are typically not available except to Miller techs. You may find one on ebay periodically--slim chance, but possible, and certainly not on your hot schedule.

It doesn't sound like you have the actual owner's manual, which has the schematic diagram and pictures of the parts layout with parts lists. You can download one here:

https://www.millerwelds.com/support/manuals-and-parts


Just put in your serial number in the box at the lower left. The schematic will tell you which wire numbers connect where. If you are not familiar with the way Miller shows relays on their diagram, it will be confusing. They show the coil as a round or octagonal circle with a number inside, like CR3. But the contacts are scattered over the diagram, and you have to search for them. Example of CR3 posted below. This is the schematic for your machine from the link above.



The pinouts for the relays can be found on the internet--the relay should have a manufacturer name and part number on it; put it in a search engine and look around. I don't think I've ever had a case where I couldn't find relay info on line. You can tell which wire number goes to which pin from the schematic.

I can't comment on the control transformer--not sure why someone would do that.

The fuse you replaced -- you indicated 250v. The voltage rating on a fuse in a welder is not significant. The important thing is, did you put in one with the right amperage--that's the key.

Your rectifier replacement is fine--higher ratings are good.


Don't understand your statement about the "copper wire inside the spring is just barely touching the springs". Can you post a picture?

[welderman2020]

The copper wire I was talking about is the wire on the brush that goes to the base plate on the spring and the relays have no info only because they look like they been there for awhile and looks like it was rubbed off I will post some more current pics of the working progress that is the exact wiring diagram the welding shop gave me. Is there a way to test the relay to see which energizes and which is normally open or normally closed or the commons. I'm not used to dpdt, also I have no 120v to check to see if relays open and closed just yet.

[welderman2020]

Here is the current pics of the working progress the one wire #32 coming off the brush going into the resistor by looking at the schematic says there's a ground tied in so idk if that's right or not but I tied a ground onto it. Also is the rehostat suppose to have a jump wire from middle post to the post on the right as well, and the fuse is 250v and 15amp I believe that's what I found in the manual online. You can see from the relay pic there's no schematic like it was rubbed off the face of it.

[Aeronca41]

The ground on wire 32 is good.

Yes, you should jumper the center terminal of the rheostat (actually a potentiometer being used as a rheostat) to the one on the right that is unused. Keeps some resistance in the circuit even if the moveable arm loses contact with the coil for some reason. Just a design safety feature for the hardware

You can probably figure out the relays with a car battery, some test leads, and an ohmmeter. First, find out which terminals are the coil--should be able to see them through the plastic case and follow the wires. Those are 12 volt DC relays, not 120 volts so if you jumper the two coil terminals to the car battery (or a battery charger) the relay should click. [Be VERY CAREFUL that you have the coil pins--if you happen to connect the battery between two contacts that are "making" inside the relay, there will be a very short period of fireworks before the relay is destroyed. ] Then, you can use an ohmmeter on the other (contacts) terminals to see which is the common (moveable) terminal by checking continuity between the normally open and normally closed contacts.

[welderman2020]

I hope this is the correct book since I just printed out 68 pages. Please confirm

[Aeronca41]

Miller differentiates between the Legend and the Legend NT (which I think stood for New Technology). The date on the manual you posted is 2/96, for a Legend. Your welder owner's manual is dated 8/98, which makes it a Legend NT. Only a Miller tech is going to be able to tell you how close that tech manual is to your machine--no way to tell otherwise. And that might get interesting, because the official Miller position is users are not supposed to have that manual in the first place.

What I think I can safely say is it is not the right manual, but no way of telling how close or far it is from right. Not something I think you can rely upon to rewire your machine--you are far better off with the schematic in your owner's manual--at least that matches with your serial number.