Also have you thought of what soft ware you are going to use to drive your machine?[/QUOTE]


Shortbus,

My plan is to use Mach3, but the was this little project has started out, who know what I will use. I really didn't think the power and driver hook up would be this difficult. I was expecting to throw some signals, and power at these drives and motors and be having a beer already as they moved around hahah. Who would have thought that getting some really heavy duty free stuff would be the big problem hahah.

 

Alright I am finally beginning to put a plan together here. I just have a couple more questions.

1) In the schematic is shows a 25000uh capacitor and it looks like a 500ohm 25watt resistor. I don't have those. I will need to purchase them to steady out the voltage from the bridge rectifier. What current should I purchase. Is it directly related to the current that will be put through it, or does it need to be oversized, or what. They are pretty expensive from what I can tell.

2) This is a dumb question. I can't actually believe I am going to put myself up for the abuse that it invites. I want to know if 40vdc at 31 amps would give me a shock. How dangerous is that voltage and current? I mess with 24vdc all time at work, it is only like .5amp though. Just don't want to die because I was too macho to ask the question.

Thanks

 

Alright I am finally beginning to put a plan together here. I just have a couple more questions.

1) In the schematic is shows a 25000uh capacitor and it looks like a 500ohm 25watt resistor. I don't have those. I will need to purchase them to steady out the voltage from the bridge rectifier. What current should I purchase. Is it directly related to the current that will be put through it, or does it need to be oversized, or what. They are pretty expensive from what I can tell.

Get a 500 Ohm 25 Watt power resistor. Wire wound is fine. If you want to use less expensive resistors, you could buy five 100 Ohm 10W power resistors, and wire them in series. This provides a minimum load for the supply to keep the voltage from rising too high.

The cap will probably run around $30 - $50. It doesn't have to be exactly 25,000uF, but it should be in that range. It should be rated for at least 100V. Otherwise, leakage current may be excessive, which will cause heating. You could use several 100v rated capacitors in parallel if you wished.

2) This is a dumb question. I can't actually believe I am going to put myself up for the abuse that it invites. I want to know if 40vdc at 31 amps would give me a shock. How dangerous is that voltage and current? I mess with 24vdc all time at work, it is only like .5amp though. Just don't want to die because I was too macho to ask the question.

Safety questions are never "dumb". If you aren't sure, you are far better off to ask advice than to risk injury or damage.

40vdc is a pretty safe range. You might feel a tingle if you happened to put two fingers across a 40vdc supply, but not much more.

However, the current is a very different matter. You should not wear rings on your fingers, metal jewelry around your neck or wrists (including watchbands) while working on such equipment. If you should happen to short jewelry you're wearing across 40vdc with as much power available as their will be, you will likely suffer a very serious burn, along with the jewelry item being severely damaged or even vaporized.

 

1.5kVa is a ridiculous transformer for those 3 motors. The original big transformer was probably powering a high power DC spindle motor or something.

Check my post again, I covered the motor power, and system losses. The motors will only consume about 21W each when holding still or moving slowly (most routing is done at fairly low speeds because of the cutting speed required in inches/minute).

250 watts PSU to run those 3 motors should be plenty! If you really wanted to provide some overkill you could go to 500W.

 

I hope you guys had a nice christmas.

After reading some of your guys advice, I have decided not to use the "wal-wart" I believe it was called. I have taken a power supply out of an old dell computer. It does 12vdc and 5vdc. As usual I have a question about using it. I plugged it in and put the multimeter on the pins. It looks like the only place I get current is on the 5v standby. Is there something I need to jump or do to get the power supply to work since it isn't plugged into the motherboard?

 

You need to have a load on the +5v in order to get regulated output.

Google "ATX Bench Supply" for lots of ideas.

 

Sarge,

I got it working, I'm getting 8dc out of the 5v and 16 out of the 12v is that right. That is stright output though, no load on anything.

 

You'll burn it up by running it with no load on it.

I told you already that you needed a load on the 5v supply to get proper regulation.

Why did you then think that it would be OK to power it up with no load on it, after I'd written that you need one?

Why did you think that the voltages being considerably over their ratings would be OK?

It's going to be a lot harder to help you if you don't follow even pretty basic instructions.

 

I didn't hook it to anything but a terminal bar to see what voltage it put out. That way if it was the wrong voltage i could find out whybefore it ever hit the drives. The 9 and 18 volts never went to the drives just a terminal rail. I read onthe web about building the power supply and it said I had to connect the "power on signal wire" to a ground wire to basically fool the power supply into thinking it was connected to the motherboard. I assumed that was what you meant by putting a load on it. I obviously was wrong. I'm trying to follow instructions please be patient with me. Thanks

 

Alright,

I went out and got me a couple 10watt 10ohm resistors today, and used this website to help me convert my power supply (http://web2.murraystate.edu/andy.batts/ps/PowerSupply.htm)

I connected the 5+ and the 5- up to two screws on the terminal rail. I also connected the 12+ and 12- up to two screws as well. Then I took the power-on wire, and a ground wire, put them each to a screw on the terminal rail and jumped them together. I connected the resistor between another 5+ wire and a ground wire.

So I have used 2-5+ wires, 1-5-wire, 1-12+wire, 1-12-wire, 2 -ground wires, and the power on signal wire.

According the site above this should work. I went ahead and plugged in the power supply. I used a multi meter to check the voltage between the 5+ and 5- as well as the 12+ and 12-. I got really high readings.

10v and 23v respectively. I immediately unplugged it, and wrote this post.

What have I screwed up?? I am not going to move forward until I get a response.

Thanks,

 

Sorry if I sounded like I was jumping on you in my last post.

My time on here has been limited lately by visiting friends, family, and a dead computer.

Are you certain that you're using the DC Volts setting on your multimeter? (it sounds dumb, but I really have to ask that question - if you're on AC volts, your readings will be off.)

 

Sarge,

When I look back on the previous posts and realize the dumb stuff ive done during this little endevour, you would have had the right to set me striaght. I realize you don't have to help me, and I appreciate that you have.

That being said, I AM positive that it is on the DC setting. It's not a dumb question considering my past actions hhaha.

It is an old Dell power supply, but I did make sure that I didn't use the standard pin out, I searched for my particular power supply, and got the pin out for it.

Just a side not, I don't know if it helps, but the wires I am using are directly off of the main harness ( for the motherboard) If I test the wires that are meant for the drives, the voltage is lower. It is still above five but its around 7 as opposed to 10.

Any help is appreciated.

 

Look, most of us have done dumb stuff during our experiments.

Those of us who are still posting have survived them.

I don't know offhand where things might've gone wrong, but I'm still tied up here.

 

Sarge,

I know your busy but I think I figured it out. I was taking the reading across 5+ and 5- which was 10v. But across 5+ and ground it's 5v. Same thing with the 12v. Across 12+ and ground it's 12v.

Sound like that could be it?

 

OK, then you're good.

You need to make sure that you get the grounds sorted out - and don't clip most of them off like some sites recommend.

Just take it slow, measure stuff, and if you have any strange readings, ask questions.

You're doing good.

 

Be careful, many of these commercial drivers will use the term +5v and -5v to denote the 2 power pins for a SINGLE 5v supply. So it's not a +5v/gnd/-5v supply at all, its a single +5v supply that has a + wire and a - wire!

This is quite common where the 5v supply has optocouplers. Take a look in the 6410 datasheet that shortbus posted further up the page.

I've NEVER seen a commercial driver that needed -5v or -12v for that matter, although the -12v might conceivably be needed for opamps etc.

But if there are 2 pins labeled 5v+ and 5v- that is almost certainly a single 5v supply. I have commercial drivers here labeled exactly like that.

The best thing you can do before blowing up your drivers is to really try to get a datasheet. It might be time to email Pac.Scientific.

 

Rb

i'm having real trouble coming up with a datasheet. In the last couple weeks I have called PC who said the part number was not in their system, posted on three different forums looking for them, emailed ten people who claim to fix them, emailed one person who claims to sell them, found someone selling One on eBay, and emailed him. All with no luck. You have any other ideas. The national archive maybe haha.

 

Well,

I have good news. I decided what the hell, I'm going to call PacSci again today, and see if I can't get a different tech guy. It worked. I got an older gentleman who new exactly what I was talking about, and within 10min, he had emailed me the manual for my drivers.

Amazing it's all in who you talk to. Last week "it wasn't a good part number" and today, baboom manual.

I have the a diagram as to how to hook up the drivers now. Is there any harm in putting a low voltage to the motor input, just to see if they switch on the output side? I was thinking 12vdc. I want to make sure the drivers function before purchasing a power supply for my motors.

 

I have decided its not worth messing with a transformer, rectifier, and capacitor in order to get the correct voltage. By the time I have paid for all that, I might as well have bought a power supply. I am looking at the 110-36vdc @4.2amp 150watt power supply that Sarge suggested earlier in this thread. Any reason this wouldn't power my three motors??

 

I suggest you post a link to the driver manual, it will really make it easier for people to help you.

As for the minimum recommended PSU voltage, that should be mentioned in the manual.

I would think that a 36v 150W supply would work fine since each motor takes only 20W or so, but again, lets check the manual.