SX2 broke?

[superc]

I used my SX2 for some endmill work 3 weeks ago.  It worked perfect.  Today I decided to flycut a slab.  I switched heads and turned it on.  It ran at speed (with the flycutter not yet in contact with the metal) for a few seconds, then stopped with a clunk and the fault light came on.  I'm like what?  A few seconds later the fault light goes out by itself and the head begins turning at speed again, runs a few seconds, then Clunk and it stops again and the fault light comes on and it all repeats again.  Over and over.  I tried taking the flycutter off and running it with nothing in it, but exactly  the same behavior.  So it ain't about the tool head.  Has anyone had this happen before?  Is it in the fan belt or what?  Yeah I know I need to start ripping things apart, but I am hoping someone has been there, done that and can point me in a good direction.  Pulley, bearings, motor?  Assistance requested.

[John Rudd]

Is this the mini mill with the brushless motor?

If you remove the belt , can you turn the spindle by  hand? Does it feel tight?
Will the motor run without the belt attached?

My mini lathe has the brushless motor and periodically the fault light comes on....

I'm leaning towards a motor/ controller setting being a bit too close to the edge that's causing the controller to shutdown....

I don't know enough about the controller yet to be able to sort it....

[velocette]

Hi superc
It sounds like a motor on overload possibly by the preload setting on the spindle being to tight (The Castellated Nut under the drive pulley it is retained by a socket grub screw 4 mm allen key).
Or does the motor only run at full speed the the problem is with the controller.
Check the belt adjustment is not to tight.
Remove the belt and run the motor if the problem persists then the controller or an outside chance it is the motor bearings or the armature has got a fault winding.
My turn for a question how old and how much work has the mill done it may be time for a serious overhaul?

Eric 

[superc]

Yes all Sx versions use the brushless motors.  Less than 6 months old, less than 5 hours use.  It behaves this way with the R8 tool holder removed and the castelated nut removed too.
  Okay so far everyone is moving towards the pulley/motor assembly and not the bearings which was a fear.

[superc]

 
Okay.  Problem solved and I feel really dumb.

Middle of the day I went back down to the mill and got my tools and turned it on one last time.  Concept was to put one hand on the spindle end and the other on the motor housing and see if I could detect which one vibrated first as an alternative to disassembling everything.

Kind of surprised when nothing unusual happened.  The spindle spun very nicely with no clunks whatsoever.  So, I stopped everything and put the end mill back in and tried again.  Flawless operation.

All thoughts of totally disassembling the spindle head and motor housing now went on hold while I went and got a cup of coffee and pondered the discrepant behavior.

 

Something was different between yesterday and today and the last time the mill ran perfectly.

The last time was also night time just like last night.  It ran fine then, but not last night.  Today it runs fine again.  Only difference I could think of was last night I..   Oh!  I wonder if?    Last night was cold so I plugged the 50K BTU torpedo heater into the same wall outlet to heat the basement up while I milled.  Today the basement is already warm, so the heater is not sharing the wall socket.

I started the mill and plugged the heater into the wall socket.  The heater started and a few seconds later the mill went CLUNK and the fault light came on and the mill stopped.  Then a few seconds later the fault light went out and the spindle began spinning again.   About 4 seconds later, CLUNK and the mill stopped again and the fault light came on.

I unplugged the kerosene heater and the mill ran just fine.  The outlet is a 20 amp GFI box.

I was thinking it was about current, but when I plugged in my watt/amp meter I see the SX2 actually uses way less than 500 watts.  Varying the speed varies the current load but it never passed 3 amps draw even at maximum 2500 speed.  Likewise the kerosene heater uses only about 1.4 amps.  Nevertheless the two devices somehow conflict when on the same line.

Resolution?  I plugged the kerosene heater into a different wall outlet.
I will leave it to brainier folks than me to figure out why the two devices are incompatible when on the same outlet box.  All I care about is the mill works and I have no need to take it apart.

 

[SwarfnStuff]

WAY better fix than disassembling then looking for a fault that didn't exist.   
 New day fresh (well, shall we say refreshed  ) brain to think with, good for you.
John B

[velocette]

Hi superc
mill working fine great. Heater the culprit so the answer seems to be is the heater worth fixing?
Eric

[Stilldrillin]

Sounds like a good result, to me! 

If only, all problems could be so simply solved........

David D

[lordedmond]

Has that heater got a spark ignitghter on it to fire up the paraffin ?
If it has then that very well could be the source of the trouble the HT hi frequency causing the mill to fault .the clunk would be the quill banging the same as when you reverse the mill

Stuart

[superc]

Yes it does have an auto igniter.  I had a similar thought.  Watching on the amp/watt meter every 20 seconds or so there is a current spike of about 0.2 amps.  Without taking the heater apart I couldn't decide if it was the fuel pump, the electric eye sensor, or as u suggest the igniter. 

Since both machines work just fine when on different circuits the obvious, and simplest 'fix all' is to not use them both at the same time on the same circuit.

It has to be a sub or secondary frequency causing the problem as the duty cycle of the house current remains unchanged.  I lack the apparatus to tell if one device is generating a square wave while the other one uses/expects a sine wave or a triangular wave or a sawtooth wave or vice versa.  Crest factors, form factors, RMS, all that gobbledygook.  I know in theory while my meter is measuring the waves it expects to see, there could be when both devices are in play be two or more waves running through at the same time, but the meter will only notice the one, even if there is a wave of lesser height delivering a greater RMS value.  In any case all that is pushing the limits of my understanding of things electric.  Suffice to say the torpedo heater and the Mill's circuit board are not friends.  So clearly keeping the devices on different circuits is the best solution.

I have in the past had printed circuit boards become suddenly inoperative (i.e., dead forever) when expecting one type of wave an old generator of mine sent out some of the other types of wave.  LoL, can we say; running, running, pfffft! 

[lordedmond]

looks like that the cause and you have found a simple solution to the problem

when I was working we spent months at the computer centre ( main frames  2 mega watt draw from the mains ) trying to sort out circulating current problems turned out to be a USA made and certified by IBM frequency changer in our case 50HZ to 408HZ ( may be wrong on that value it was over 20 years ago ) the problem was odd oder harmonics because the units being USA sourced were designed for 60 HZ thus the filtering was not up to snuff over here


Glad you have it sorted

Stuart

[BaronJ]

Yes it does have an auto igniter.  I had a similar thought.  Watching on the amp/watt meter every 20 seconds or so there is a current spike of about 0.2 amps.  Without taking the heater apart I couldn't decide if it was the fuel pump, the electric eye sensor, or as u suggest the igniter. 

Since both machines work just fine when on different circuits the obvious, and simplest 'fix all' is to not use them both at the same time on the same circuit.

It has to be a sub or secondary frequency causing the problem as the duty cycle of the house current remains unchanged.  I lack the apparatus to tell if one device is generating a square wave while the other one uses/expects a sine wave or a triangular wave or a sawtooth wave or vice versa.  Crest factors, form factors, RMS, all that gobbledygook.  I know in theory while my meter is measuring the waves it expects to see, there could be when both devices are in play be two or more waves running through at the same time, but the meter will only notice the one, even if there is a wave of lesser height delivering a greater RMS value.  In any case all that is pushing the limits of my understanding of things electric.  Suffice to say the torpedo heater and the Mill's circuit board are not friends.  So clearly keeping the devices on different circuits is the best solution.

I have in the past had printed circuit boards become suddenly inoperative (i.e., dead forever) when expecting one type of wave an old generator of mine sent out some of the other types of wave.  LoL, can we say; running, running, pfffft!

Almost certainly the heater is introducing spikes onto the mains and the Mill speed controller is sensitive to them !  Nothing wrong with either piece of equipment.  Putting the heater on a different socket is adding additional inductance or capacitance into the circuit between the two enough to suppress them.


There should be circuitry built into each piece of equipment to prevent that phenomena as required by various bits of legislation in various countries including the UK, USA, and most if not all Europe.   

[superc]

 
Gotta tell you, it all gave me a really bad moment when the first CLUNK and fault lights started happening.

Visions of bearings failed or bad circuit boards or even debris caught in a fan belt ran through my mind along with the vision of what to dissect first. 

Truly was some luck involved.  First, that the mill's circuit boards didn't just go pffft like another piece of equipment did long, long ago.  Second, that I had no heater in the circuit on the day I turned it on one last time before beginning dissection.  Third, that I made the connection between what is the now, and what was different then.

Well the proposed legislation does sound nice, but I suspect the 30 year old torpedo heater won't give a hoot and will continue to dirty up the power lines.  I think this problem is why some places I have worked have isolation transformers between different pieces of equipment.  Seems strange to encounter a situation inside a home workshop where that might not be a terrible idea.  Also noting Baron that you didn't add the home of Sieg, ie.e., China to the list of places where the legislation is being considered.     

[Bluechip]

Trouble with the usual wretched L/C  line filter is they are not very good a stopping really narrow spikes. Presumably due to the self inductance of the X-Y caps and self capacitance of the chokes ... ?

If you have problems just nail a 275VAC and > 80J MOV across the mill AC input, ( assuming you are on 240VAC ).

Cheap enough, about 70c or 50p in UK.

Similar to this:

http://uk.farnell.com/littelfuse/v275la40ap/varistor-140j-275vac/dp/1057203

They do tend to snuff it over time.  One machine I worked on we were supposed to replace them once a year ... Don't know if anyone ever did but it was scheduled ... Me? No, I never did ... 

Dave

[superc]

No it is a 110-120 V AC Mill.  Supposed to be a 120V 60 Hz line.  Yes, sometimes it is.  The UPS on this computer says the power company is supplying 122-127 volts today.

[BaronJ]

Well the proposed legislation does sound nice, but I suspect the 30 year old torpedo heater won't give a hoot and will continue to dirty up the power lines.

[/size]I agree. :-)  At 30 years old the legislation didn't exist when that heater was made. [size=78%]

I think this problem is why some places I have worked have isolation transformers between different pieces of equipment.  Seems strange to encounter a situation inside a home workshop where that might not be a terrible idea.  Also noting Baron that you didn't add the home of Sieg, ie.e., China to the list of places where the legislation is being considered.   

Actually the manufacturer is supposed to manufacture the machines such that they comply with the [/size]legislation in which ever country they are sold !  But it does seem that this is not always the case.[size=78%]

[/size]Bluechip offered a viable solution although I would add an LC filter to the heater and feed the mains to the heater through it.  A ready built solution would be to fit an IEC filter socket to the heater.  These are available with 10 or 15 amp ratings.  Indeed if you were in the UK, I could give you half a dozen...  At least they wouldn't end up at the scrap yard or in landfill. [size=78%]

[MetalMuncher]

Interesting tale, SuperC!

For my own knowledge, do you know if the power outlet to which you moved the heater, and solved the problem, happens to be on the same 120V leg of your incoming 240V, or is it fed from the other 120V leg? Just curious. I've not encountered anything like this before, but will surely keep it in mind for any head-scratching similar problems in the future.

Glad you found the solution before having to tear stuff apart!

[superc]

Of course I would have to take the circuit breaker box apart to be sure, but I believe both outlets share the right hand bank of switches on the house box, but are not on the same switch.  No idea at all if that has any relevance to your question.

[MetalMuncher]

Not really. ;)

One branch feeds the left side (typically the odd numbered breakers in a service panel) and the other branch feeds the right side, even numbers. So all I am really asking is, comparing those two electrical outlets, are they both on either even or odd numbered breakers, or is one odd and one even?

Since this house was built in the 70s, we have had to replace EVERY ONE of the many "push in" wired outlets and switches due to loose connections over time. So, some years ago, having met with the frustration of which breaker did what so many times, we decided to map our service panel to all the circuits in the house. Using one of those tracer tool sets where you plug the transmitter into an outlet, then go find which breaker feeds it with the wireless receiver, it only took us a few hours one weekend to write it all down. Then I made two tables in a Word document that lists them both by breaker number and then again by circuit served. Now when I need to work on something I just use my smartphone to look up which breaker to turn off. VERY glad we did that!! I also keep both lists printed near the service panel, in case my phone isn't working for whatever reason.

I was just curious about this, because I remember we once had a set of wireless intercoms that used the AC power lines to communicate between them. The one stipulation was that all of the intercoms had to be fed from the same incoming service transformer (so you couldn't have one, for example, at your buddy's house next door and talk to him too). Not sure why that mattered, but it is the first thing that came to mind while reading your solution. I presume all of your house and basement are on the same panel, so the only pertinent scenario, if one applied at all, to my line of thinking is separate branches of the main feed.

[superc]

I have had electricians add several extra outlets over the past few decades.  It was interesting because there were some weird electrical decisions made by the original builder.  Things like an outside light socket being connected to the guest bathroom circuit rather than the much closer circuits in the kitchen, etc.  Got at least 4 110V circuits in the basement, but they all go to the same side.  No idea from upstairs if that is an even number or an odd number.  If 1 is on the left, then the right should be odd, yes?

[MetalMuncher]

Only if you live in Australia. (i.e., moss on the South side of trees). 

Odd numbers 1,3,5... on the left. Even numbers 2,4,6... on the right. 

If you don't know which breakers feed those outlets, that's OK. I was just curious. I know figuring that out can be a headache. Especially if you are working all alone at the time. Even with the tracer we used radios to communicate so we didn't have to run up and down the stairs. ;)