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11th November 2011, 12:26 AM #1
CNC controller in PC case , black out proof ?
i bought a dud of a china made CNC , discontinued line ( i wonder why )
it was dam cheep and im proud i bought it ,. could not by the parts for the price they were on ebay
ive had the controll box moving the x,y,z nice and smooth
but the VDF installed was a dud , the mosfit's were not toughing the heat sinks ???? so have to rebox it to fit a new vfd
tonight's effort
since I had an old PC case lying around that was about the volume i need , it got stripped back to bare shell tonight , and a pair of 240 volt 120,mm fans fitted to it , i gutted the blown up power supply ( lightning hit my bore and blew every thing up in my house ) and fitted 3 x solid state relays on a heat sink , a 6pin control plug , power" in" and switch , will have to cut a hole for the second power in ( on same phase , separate 10amp fuse )
the dream
with this build i hope to sort out the power " black out" problem , 2x 240 volt inputs , 1 for the steppers and control side , a separate 240 volt input for the heavy load spindle , cooling pumps and fans , compressor,vacuum pump, ect if the power gos out UPS units will keep the PC and mach3 controll powered for over 3 hours , and switch to pause ,
, once the power comes back on , hit resume ,
in the build up and wet season Darwin will have 3 black outs a day , most for less than 5 sec , but enough to stuff up your job
will also try to shield most high noise items inside the case
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11th November 2011 12:26 AM # ADSGoogle Adsense Advertisement
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12th November 2011, 10:03 PM #2
did a bit more on it today , wired most of it up ,lol , birds nest and now shielding the "out " cables
i used aluminium foil tape , its quite thick left over from installing sky lights , and raped an extra earth wire around the foil , then heat shrinked the lot
all the cable is 2.5mm^2 (stiff stuff) salvaged from house power point wire , the low voltage side wire is salvaged from a PC power supply
there's a large earth terminal block screwed to the underside of the box
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14th November 2011, 01:05 AM #3
got the power supply box all closed up and bolted in , the 3 power plugs are for the spindle water pump and cooling fans ,dust extractor ( small cyclone vacuum cleaner ), + 1 more
was hoping that a very small compressor would be adequate for a mist cooling set-up , will have to look when the unit turns up ,
only have 1.1 amp left ,so might rewire the internals to put the 3rd plug on the other line ,over 3 amp free on that line
started on the internal wiring , most of the long high voltage wire's / spindle out wires , will travel under the floor of the box , i have a 15mm gap between the floor and the out side of the case
got the stepper controller , 5v & 12v bolted in , i removed the floor under the stepper controller so air can escape from the heat sink ,lol, ,l i only need the the 12v to power fans
got chased out of the shed tonight by the bugs , gotta love the buildup , and the termite queen fly nights ,
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14th November 2011, 06:08 AM #4SENIOR MEMBER
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- Maryvale, Queensland
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- 2,338
Boy, you've been busy. Wish I had your ingenuity, I'd save a fortune!
Pen Affair Craft Supplies - Cheapest Pearl Ex & Pemo Polymer Clay in Australia
http://craftsupplies.penaffair.com
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14th November 2011, 10:17 AM #5
The ingenuity only follows after a fair bit of study Russell. Sawdustsniffer must have a reasonable background in electrics / electronics to do some of the things he does.
But he also gains points for some strange sexual proclivities.
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14th November 2011, 06:56 PM #6
yer "Dicksmith kits" when i was a kid , lol , in the 70's i was 10 getting 240volt kits for xmas , i think the "Nanny State people " have banned the sale of 240volt kits now ,
the old dicksmiths kit instructions were great , explained what gates were in the chips and why they used them , and then my dads policy of let the kids destroy any equipment before dumping it also helped ,down to waring rubber gloves , and opening up capacitors and unrolling them to find there????"al-foil and wax paper"??? we even pulled a 202 red motor out of the tip so we could pull it apart , lay it out on the shed floor , understand how it works and dump it 2 weeks later in bits ( free entertainment before computers ?//)
a good "pay out" on site to "Sparkys " is " you have no understanding of basic logic " ,
once you understand TTL logic gates , the little black things with silver legs and numbers on top dont seem hard to use at all
and typo's are typo's dam spell check
the best advice i can give Boomer is the " twisted complimentary Pair " if you twist a "Direct current(DC)"+ and - wire around each other you will minimise magnetic interference , as long there is the " same" amps flowing in each wire , one positive one negative , there magnetic fields will cancel each other out and protect each other from out side interference ( almost) , so your stepper A+ and A- should be twisted together inside the box , and B+ and B- twisted , just keep 240volts way from low voltage wires ( dont bundle them ) , and cross them at 90 degrees , if its got an earthed , metal cage around it , its shielded
twist any "complimentary pair" in side the box , search the forum for " inside case" photos , and look for twisted cables ( 2 only )
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16th November 2011, 07:16 PM #7
bits are turning up
today my 12lt/min 240 volt water pump turned up , as well as my Mist Cooling head , ( on top of the radiator )
the water pump looks the business , complete over kill in size , i need about 3lt / min to cool the spindle , so most of the excess water pumped will recirculate through the radiator ( back ground in photo )
the sticker on the pump it says 0.4 amp at 35psi , 12lt/m open flow , so will have to test its flow and Amps at 20psi
cool a 0.6Amp bonus , i was expecting the water pump to drain at least 1Amp of my 3 Amp left over of the spindle line ( 7 Amp spindle ,10amp fuse )
the 3rd , 45amp solid state relay has 2 out put wires , one go's to the VFD spindle controller , the other to the cooling pump + cooling fans on the radiator (240 volt fans ) , on the face plate of the PC case will be a Single Pole Double Throw (SPDT) switch , that will let me select ,
(A) Mach3 control ,
(B) , OFF ,for probing , one of the 2 " 1/8 jack " out puts on the front face of the PC cabinet , will be the probe jack
(C) , Manual over ride ON ,
if the VFD is on the cooling pump is running
same with all the 3 of the 240 outputs on the back of the case
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17th November 2011, 07:45 PM #8
And you learnt all this from a few Dick Smith kits eh?
Bob Willson
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17th November 2011, 08:05 PM #9
lol and tinkering , learnt respect of high voltage and magnetic interference from making Tesla Cannons , lol it fired 150mm round bore casings into trees , very dangerous , start the generator and in 5min it will fire ( you have ran away from the tailer mounted cannon ) 3 garbage can capacitors full of aluminium foil and gladrap , and used rat traps as switches do not build one dangerous as all crap , lol was running it at 120kv , at about 10 million Jules, even the site i posted pictures on ,had the thread removed for safety concerns , a 10 foot fibre glass pole with a shorting out rail at the end was a must , the capacitors would charge them self up with no power connected , if they didn't have the shorting straps between the terminals
did electronics at school but that was pretty basic
carpenter by trade , but cant resist looking how a LNG gas plant is wired up when working there , just what parts they use , the screening ( fire proof ) , ect
now I like to use the new ( last 5 years )" basic programmable boards" , program them via a USB , and after there unplugged they run the program , the "Carmelians" i have have 32 out puts , you can use them as you like , each pin can be digital or analog , in or out , and can bundle the legs up as 4bit , 8 bit ,16 bit ,32bit in or out , there fantastic to use , VB interface and all
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17th November 2011, 08:08 PM #10SENIOR MEMBER
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- Sep 2008
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- Maryvale, Queensland
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- 2,338
Pen Affair Craft Supplies - Cheapest Pearl Ex & Pemo Polymer Clay in Australia
http://craftsupplies.penaffair.com
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17th November 2011, 08:28 PM #11
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17th November 2011, 11:22 PM #12
if you doing some wiring you should " understand " a few things
ohms law Ohm's law - Wikipedia, the free encyclopedia
http://upload.wikimedia.org/wikipedi...iangle.svg.png just need to remember this triangle
this is a great way to remember it , you need 2 measurements to work out the 3rd
so V = I*R
I = V/R
R = V/I
if you had an LED that needs 20milliAmps to light up and were running a 5 volt circuit then the resistance needed to obtain 20milli Amps would be R=V/I , so 5volts /0.020 amps = 250 ohms resistance
wire type , there are 2 parts to a wire , the wire and the insulation
the wire gauge will allow amps to flow , insulation will keep volts contained
so with Amps worry about the thickness of the copper cable , with the volts ,its the thickness / quality of the insulation ,
if you make your own wires on a circuit board , amps is how wide the strip is , volts is the spacing between the strips
when a wire transmits a" electrical potential " it will form a magnetic field around its self , it has to form this field witch takes time and energy to form , and when the electrical potential stops , it will decay and form electricity back into the wire ,
this is called " inductance " ( why leaving extension cords coiled up is bad )Inductance - Wikipedia, the free encyclopedia, this decay of the magnetic field happens faster than it formed and can produce a "spike " of up to 1.4x the voltage that made the field , if your running 48volts , you need atleast 1.4x more voltage rating on the components
magnetic fields around wires is well know with the "left hand rule "http://en.wikipedia.org/wiki/Left_hand_rule , dont have to read it , just know it happens
so now you know every wire is forming , and collapsing its own electromagnetic fields around its self , these fields can interfear with other wires , ie a 240volt light cable running along side a Z axis 5volt limit switch wire , , the 240 volt 50Hz wire can produce a current in the 5 volt limit switch line , if the "interference " boarders on the " cross over voltage " ie 2.9 volts , you will get an intermittent "glitch" that is a bugger to track down
the BOB says its 0volts for off , 5 volts for on , ( not quite )
you will find 0-2.7 volts is off , 3-5volts is on ,
on outputs wires the interference wont do much ,might make the steppers run a bit rough with a 50hz buzz ,that will cause harmonic problems and will lower your top speed
with inputs it could run amok and cause all sorts of havoc
so electromagnetic shielding comes into play , basically if you put a metal cage around it , the magnetic fields will deliver there intermittent currents to the metal , and if that cage is grounded , it wont build up a voltage
Electromagnetic shielding - Wikipedia, the free encyclopedia
also a component that dosnt draw the same amount of electricity all the time , will have its input wires changing amps all the time ( stepper motor drivers ) , this causes the magnetic field around the wires to collapse , regrow , collapse regrow ect , so your nice out put from a power supply gets less volts and more volts from the magnetic fields growing and collapsing as the amps change in the wire , Sub woofer car audio nuts put huge capacitors on there amps for this reason and stepper motor controllers should have a capacitor across there + and - terminals as well (must have with switch mode power supply's , transformers dont really need them )
Your filter capacitor on your power supply is determined by your power supply voltage and current.(80,000 * I) / V = C ,
ie (80,000"magic number " times "Amps " divided by "voltage " equals the capacitors size
, and the voltage rating of the capacitor should be above 1.4x the voltage of the power supply
this capacitor will then deliver the voltage and amps direct to the board , the capacitor will absorb the fluctuating current , and the input wires will have a lot more stable flow through them , keeping the voltage and amps where they should be
there are a few other problems that can sneak into a TTL( 5volt data) amplified circuit ,
one is voltage drift , where a wire that is OFF slowly starts to gain "elections " and its voltage rises , untill it opens an "amplifier/ gate" then drains ,and shuts the "amplifier/ gate" down again ( intermittent problem ), to make BOB's built proof , connect a 1M ohm ( 1,000,000 ohm) resistor from each output to ground , there is so much resistance in a 1M ohm resistor it will only drop the voltage on that pin by less than 0.1 volts , but will ground out any small rise in voltage when the pin is off
the next worst problem is " debounce " , any input into your bob , has to be debounced , when any switch contact comes close to closing , small arc's start to form , the closer they get the more they arc , until the 2 surfaces of the switch contact each other , TTL ( 5volt Data) will interpret this as the switch being pressed a heap of times , not once , so a small circuit has to be added to put a time period of the first arc , 1/100th of a second works well , as soon as the first arc happens , a circuit board , holds the 5volt data line "closed " for 1/100 of a second , so only 1 contact is registered every 1/100th of a second
1/2 way down this page http://en.wikipedia.org/wiki/Switch
hope that helps some people
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18th November 2011, 10:05 AM #13
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23rd November 2011, 10:23 AM #14
still waiting on parts , the Ghan turned up yesterday so should get a heap of mail today , pretty well come to halt until more parts arrive
so got back into my CAD drawing
i purchased Turbo Cad , with the CAM plugin , and have started my first project , lol , learning CAD as i go ( slow )
lol my 1st cad / cam / cnc project is a tough one , it has to be done and i set the bar pretty high
" A mould for a Carbon Fibre Violin "
top and bottom Plate moulds , Rib mould , Neck Mould , Finger board mould
the material will be HDPE , carbon fibre resin dosnt stick to HDPE ( polished )
will machine some MDF test peace's first to check code , and i need a copy of the mould in MDF to use as a vacuum holder , to cut out the shape and F holes
100 points by a 100 points in the mesh , thats 10,000 Z heights have to be entered ( each z height dragged and dropped ) use the snap settings and quite rough at the moment , will have to zoom in and go through each mesh point and raise the accuracy to 1/100th of a mm
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23rd November 2011, 12:47 PM #15SENIOR MEMBER
- Join Date
- Sep 2008
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- Maryvale, Queensland
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You don't do things by halves, do you? And TurboCad is still going? I think I remember trying it back in the DOS days? Aspire is my one & only CNC program. It cost a oretty penny, but I'm not sure how easy it would be to do something this complicated. I was also considering Rhino3D for full 3D models, but I'm still trying to crawl, let alone run
Russell.Pen Affair Craft Supplies - Cheapest Pearl Ex & Pemo Polymer Clay in Australia
http://craftsupplies.penaffair.com
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