A New CNC Build

[rodm]

Hi Ed,
That is terrible news. I have admired your work from your first thread and I hope you can get back on your feet and build things up again.
Wish I lived closer and could give you a hand to clean up.

[appiwood]

Hello Russell / Rod and Group

I have attached some photos of the fire damage, with the message, don't stop thinking what can go wrong ( welding spark into an open sleeping bag isn't good ) and do you kow how much replacement cost is in you shed / workshop??. Looks like most things will be replaced but not all, I'm still working on what was lost and won't be covered by insurance, it would be enough to setup most " average " workshops, but not ours!

Well one photo the is the " before " the after ones won't re-size but think black charcoal and you will be close.

Ed

[Zoot]

Ed,
I don't think I want to see the 'after' photos ... far too horific! I could not even emagine how I would go about itemising all the gear in my shed, needless to say there is stuff there that goes back 40 odd years to when I was an apprentice carpenter. I feel for you.

Cheers,
Alan

[rodm]

Hi Ed,
I hear what you are saying. We keep adding to our collection without realising the value of what we have.
I hope you can recover from this with a new shed and enough gear to get you up and running again.
That machine was looking a treat too.

[epineh]

I think I am with Alan, that machine looks too nice to see it all charcoaled...

Russell.

[seafurymike]

Ed,

Terrible news. I hope you get back on your feet with the shed business soon.
I know mine is a home away from home and would find it sad not to be out there tinkering away.

You do raise a very good point on insurance. Is it true that they only value tools at 10% of your total contents value? After the fires that roared just up the road only a few months back i have been meaning to look into this fact - my first job for tomorrow.

Best of luck and if we can help in some way, you only need to mention it.

Michael

[Geoff Sims]

Hi Ed

Sorry to hear of your misfortune. Enough to knock anyone for six. Hope you're back up and running again real soon.
Geoff

[Greolt]

ED

I know it is just words, but I would like to add my good wishes.

Just don't know what I would do if that happened to me.

Small part of the total but that was one nice looking router there. Sorry to see it go also.

Greg

[stevejw]

Hi Ed,
Sorry to hear about all your gear and the shed, I am not sure what I can do to help except offer moral support as the other members have done.

I think Ed's posts about his fire are a timely warning to us all about being careful in the workshop with lots of flammable stuff and then lots of ignition points.

Best regards,
Steve

[WillyInBris]

Well Ed all I can say is FAAAAAARK sorry to swear but just reading your post leaves me feeling empty and we haven't even met as yet.

I guess the main thing is no one got hurt I cant say anything more then swear.

I have often thought about insurance for our stuff and how much it would be I think I may have to give the insurance company a call and see what options they have.

Onwards and upwards I guess but I really have no idea what that means

Sean

[Geoff Sims]

Hi all

I’m looking to start planning and putting together my control box and power supply and have come up with the following. I’m hoping someone with a bit more nouse than me can cast a critical eye over my calculations and let me know if I’m on the right track.

My motors are model 24H290-35-4B Steppers and I will be using Gecko 251s, and a C10 BOB.

The motors' specs are 3.5V, 3.5A/phase, 387 oz/in, 1.8 degree. Like most, I’m going to use a toroidal transformer in a simple power supply.

With the maximum voltage for the Geckos at 50V, I reckon the toroidal’s secondary needs to be about 35.5V, so a toroidal with a secondary of 35V should give me about 48-49V.

Since I’m using 3 x 3.5A steppers = 10.5A, and I believe I need only 67% of that at any one time, a secondary current of around 7A should suffice.
The power rating of the toroidal needs to be 35V x 7A = 245VA.

Looking at what’s available, I can get a 35+35V, 300VA toroidal transformer at local supplier Altronics which I reckon should do the job nicely. It also has extra secondary windings at 15+15V and 12+12V (500mA) which could be handy for running cooling fans, etc.

I’m also thinking that an 8000uF filter capacitor would be sufficient. Perhaps 10000uF?

Any advice please?

Cheers
Geoff

[Greolt]

My motors are model 24H290-35-4B Steppers and I will be using Gecko 251s, and a C10 BOB.

Looks a pretty good combination. Consider Homann Designs BoB. Similar specs as the C10 but made here in Melbourne.

http://homanndesigns.com/store/index...products_id=59

Looking at what’s available, I can get a 35+35V, 300VA toroidal transformer at local supplier Altronics which I reckon should do the job nicely. It also has extra secondary windings at 15+15V and 12+12V (500mA) which could be handy for running cooling fans, etc.

12v and 15v (16 and 20v DC) might not be as useful as you think.

Fans are often 12vDC; and 5vDC regulated is often needed for the logic stuff.

I’m also thinking that an 8000uF filter capacitor would be sufficient. Perhaps 10000uF?

Probably want about 12,000uF. How about two 5600uF (R5573) or three 4700uF (R5563) and a board to mount them on (K3015).....(Altronics part numbers)

I had a box of large filter caps that I was passing out, but unfortunately I have given them all away.

Greg

[appiwood]

Hello Geoff


I have used the formula found somewhere on the net ( most likley from the Buildyouridea.com site ) of Cap = (80000 * current ) / volts

Using that I get closer to 16000Mfd.

I don't know how true this is but I have seen / heard it said that the caps are also to store generated power when the motor is driven by the gantry - I have no idea if this is true or not.

Singed ( <<<< maybe a new tag??? ) Ed

BTW - I could find some cooked caps if you are interested 8-)))))))

[epineh]

Personally I use a general rule of 1000uf for each amp of motor current...my servo's pull about 4 or 5 amps each when stirred up so I made the minimum cap size about 15000uf.

Of course then I found an 80,000 uF cap so I kinda blew that theory out of the water

Jaycar sell a nice 10 000 uF cap with mounting ring for a reasonable price, two of those should suit your needs as 10 000 is probably a little close to the mark, they are nice and compact as well. (my 80 000 is like a beer can on steroids!)

Cheers.

Russell.

[Geoff Sims]

Greg
Thanks for your advice. I thought the extra windings on the transformer may be handy, but if I can't use them I'll just leave them insulated and disconnected.

As far as the filter capacitor is concerned, I'll take your advice and go higher. I'll use two 8000uF connected in parallel. They are chassis mount and a reasonable price.

I already have a C10 BOB on hand, and Peter's website says he's out of stock and shows no technical info about his BOBs. So, I'll go with the C10 for now and may change over later if his has advantages.

Ed
Using the two 8000's in parallel should get me your suggested 16000uF.

Err, um, thanks for the offer of the cooked caps. I don't want to seem ungrateful, but, I think I might pass.

Russell
If my three steppers pull 3.5A each, using 1000uf for each 1A equates to 10500uf. So, along with Greg and Ed, you've convinced me to go higher. I'll go with the 16000uF.

Cheers all