What your multi meter says, did you take any measurements?Quote:
Originally Posted by cropwell
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What your multi meter says, did you take any measurements?Quote:
Originally Posted by cropwell
No Sir, It was working fine as a VFD before I took it out. My next step is to double check the connections, but not today, I have had enough. I will start fresh tomorrow, but tonight is beer, roast chicken and relax.Quote:
Originally Posted by Nickhofen
This will be a new thread I'll bet. I don't want to hijack yours !!!
Neat layout.Quote:
Originally Posted by Nickhofen
Minor observation:-
It can be a good idea to wire a bleed resistor across the output - nothing too big, but enough that you're not holding a substantial and dangerous charge long after removing the power.
Also, there's some concern with the use of screw terminals particularly with high-current circuits and when vibration may be present that the screws can loosen over time.
Do not worry about hijacking this thread,just bring the chicken and beers, I will buy some souvlakia with tzatziki also,lol!Quote:
Originally Posted by cropwell
Thanks for the observation ,can you point me a value for the resistance and how many watt it should be? I have some laying around here at home.I will change the terminas as soon as the other ones come with the mail.Quote:
Originally Posted by Doddy
Value?, pick a number. I recently ordered 1500 Ohm, 7W wirewound resistors for an 80V supply. Just remember Ohm's law - you can determine the power rating from the voltage and chosen resistor value (P = V*V/R) - the lower the value the quicker it will discharge, but the beefier the resistor needs to be, and the more energy you throw away.Quote:
Originally Posted by Nickhofen
I went DC because I have two AM 882 and waiting for other two AM882h to come,so DC was one way road....Quote:
Originally Posted by Desertboy
I'm going to engage pedant mode for a moment.Quote:
Originally Posted by Clive S
It's not to do with volt drop, it's mostly to do with the risk of harmonics.
Stepper drivers are essentially a complex switched mode power supply, which means they don't draw a constant current, they're constantly switching at high speed. If you place multiple of these on the same wire, then you risk harmonics, which is where multiple spikes at the same time lead to high voltage spikes, which can destroy electronics very quickly, and in extreme cases will burn out the wiring, even though the total current may be well within the current limit of the wiring.
Off course the latest drivers are far more likely to contain some internal filtering to help avoid noise being propagated into the supply, as part of them meeting various approvals, which should avoid any harmonic problems.
Avoiding daisy chaining also helps minimise any potential damage from a failed connection, as a connection failure during deceleration is very likely to result in an overvoltage failure, with resultant smoke release from drives. By having them wired direct, the worst case is one drive fails, but if daisy chained, you risk every drive after the bad connection failing.
Personally, I always wire drives directly to the main smoothing capacitor, as it avoids having any more connections in the wiring than needed.
Trad English Roast Chicken, Stuffing, Roast potatoes, parsnips and braised carrots, None of this forrin stuff :glee:Quote:
Originally Posted by Nickhofen
If you use a 5k bleed resistor, you will not have enough current going through it to significantly affect the PSU in operation and a 2W resistor should handle the current. I don't know what capacitor value you have but 5K will bleed down fast enough.
A bleed resistor might be useful while you are testing, but once you have a driver or two wired to the power supply, they look like a waste of time. When I checked my machine, the stepper driver power supply was down to a few volts within seconds of cutting power. Any resistor that drains down faster than that is going to need to be a fairly high wattage item, and is going to produce more heat than you probably want in the control box.
Provided that the drivers are energising the stepper coils, and are connected, and that there are no failures in the system, and that there is no e-stop isolation.Quote:
Originally Posted by Neale
I'll spend the £1 extra on any >50VDC PSU. Pays your money, takes your choice.
I know on the AM882 when you kill power the LED's flash for ~3-4 seconds extra then when you test the capacitors they drop to a few volts. Same with the VFD so I assume that has a load of capacitors as well, also if you notice PC's do the same thing.
I think it was joe's build where he used a resistor to drain the capacitors which I was going to do but given the AM882's drain them anyway I figured it wasn't a major issue.
I've been shocked with 240v a few times over the years lol but the worst shock I ever got was from a Playstation 2 PSU for several days afterwards I felt in physical shock, last shock was direct from the board lol we have old school fuse holders at work for each phase and one of the fuse holders was missing the screw caps so when I pushed the fuse into the board I was touching the screws than was fun ;)
Oddly enough I went through every fuse holder and chucked the ones missing the caps after that.
I am starting to flirt with the idea of UC300eth and UB1 any opinions and ideas from where to buy are welcome.
I recently purchased my UC300eth and UB1 combo from CNCRoom and UCCNC software from CNCdrive! Its a smaller world nowadays...
Thank you for the reply, have you give it a try yet?Quote:
Originally Posted by Krammer002
It'll be a while before I'm ready to deploy the control system fully, but I will be bench testing in the near future...
I've also purchased the 2017 screenset from Gerry - CNCwoodworker . with a view to creating my own screenset in due course!
Very nice - I need to do a proper power supply at some point too.
Good work!
Thanks, I am sure you wont have problem to build it!Quote:
Originally Posted by Zeeflyboy
You find things out which are peripheral to the problem - code Lv on the VFD display only means Low DC bus and this is OK when the power is running down.Quote:
Originally Posted by cropwell
But I have diagnosed the problem - I reassembled with the microswitch that is for the headstock gear train safety cover swapped with the chuck guard switch (one is NC and the other NO). So my next session in the workshop will fix that and the covers will go back on. Job done ! No need for a new thread:beer:
Those are good news cropwell, an easy fix is always preferable than something that will cause headache or need money to be fixed,right? ;-)
UC300 with UB1 will cost 320$ with out shipping and taxes,this is far away from badget right now.....:devilish:
I feel your pain, that's why I setup with PP BOB originally as the budget just wouldn't stretch over Xmas period so I could play with it, do some calibration and decide if I got on with linuxcnc before spending £300 on hardware which locks me into a vendor I haven't even tried.
I remember you saying you've used mach before so being locked in is probably not an issue to you.
When I was able to sell a kidney I got my electronics ;)
Ironically now I have a machine with good latency I can run it at 9m/min no issues from the PP BOB with 8 microsteps which has made the mesa less essential but obviously I'm still going to use it.
Yes you remember correctly,I am going to use Mach3 again.
My new senario is to take the uc300eth-5LPT and a crap break out board until I decide which of two kidney to sell,haha!!
You can also sell one of your eyes and part of your liver ;)Quote:
Originally Posted by Nickhofen
Ahahahhahaa!Quote:
Originally Posted by Desertboy
I need both my eyes for my job,but I have a big nose that I can partially sell to get money for my bob....:-P
I "see" the bob problem coming and finally fix it!!!
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Hahaha photo from cnccook book!
Sometimes you have yourself do I really need all that blood ;)Quote:
Originally Posted by Nickhofen
I know exactly what you mean.You ask your self this guestion all the time especially when you build something that you do not know how it is going to come up,or if your build is going to meet your standards.
But it's a fight we have to give:Attachment 24103
I am ready to purchase the pulleys 20 Teeth HTD 5M for XY axis 1:1,at X and Y I use 1610 ballscrews.
At Z I have 1605 ballscrew what rate is recommended to use at the pulleys 1:2 maybe?
With 5mm pitch go with 1:1 ratio. This will give you good balance of speed/resolution.Quote:
Originally Posted by Nickhofen
Thanks Dean, I will do that!Quote:
Originally Posted by JAZZCNC
I start cutting and drilling parts from 20mm mdf to see if they fit right, after that I am going to use the mdf parts and my router table to shape the 20mm aluminium.
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Nice! For some parts I wish i made a trialpiece first.. smart! ;)
Skickat från min SM-G955F via Tapatalk
It is time consuming but stress relief!Quote:
Originally Posted by Nr1madman
I use the clear plexiglass to make the holes,this method is fast and accurate,no measurements to take and nothing can go wrong this way,you see thru the plexiglass where you must drill and just drill,freehand.
The you put the Plexi on the mdf or aluminum plate ,put both on the drill press and make your drills nice and square!
Small update.
First of all I want to say that I am glad for two things untill now, first off all that I start to cut the plates from mdf and not direct on the 20mm aluminium plates.:D
And the second one is that I have those thick aluminium beams!
Warning, cover your eyes this build has nothing to do with what other guys post here :-P
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I am about to order proximity switches and mechanical switches also,any recommendations ?
NPN or PNP and what about the voltages those switches,the proximity works,I find a big difference in working current...:disturbed:
NPN = normally closed. Basic Amazon ones work fine for general homing / limits (around £7 each)Quote:
Originally Posted by Nickhofen
Thanks for the reply!Quote:
Originally Posted by Chaz
Do I have to use mechanical switches also,I am a little bit confused.:-(
Nope, either or.Quote:
Originally Posted by Nickhofen
Mount the stepper motor on the Z axis,slowly growing...
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