KMB1 Conversion

[Bob La Londe]

A friend of mine painted it after I modified mine with something I think was called Glyptol or something close to that. He said they use it to coat the insides of engine blocks and cover transformers. It has worked great so far.

Well, yeah I was going to paint it with urethane varnish first.

[Dave Rothermel]

After i unwrapped the wire I didn't cut the wire till i checked the voltage first take turns off the transformer. just live the wire strung out in a pile. Hook a volt meter on each end of the secondary winding and keep checking the voltage
until you get it where you want it. As long as the wire isn't through the transformer window, it won't affect the voltage. if you need to go lower and you can cut excess the wire, scrape the varnish to hook up the voltmeter and check again. When you hook up the bridge rectifier the voltage will be higher. I think the transformer info told what percentage to lower the ac voltage. When i got the voltage where I wanted it I soldered the wire back on the terminal, rapped the cardboard cover around the windings, taped it . I didn't varnish it or anything.
Mine doesn't hum. That wire is heavy so it stays put really well. Hope this helps.
If you need to contact me direct. Dave= k9dvl@comcast.net

[Bob La Londe]

My 320X servo controllers arrived today. Dang they are tiny. About a third the size I expected. The cabinets on the mill are huge, but when I start planning the layout I run out of space quick and still make everything come out neat. This will help. I planned to leave space for atleast two more servo controllers. Now I can put them all in the space I had planned for the first three.

Thanks for the tips on the transformer. I found this site (posted earlier) to be quite useful for the math.
http://www.k7mem.com/Electronic_Note.../unreg_ps.html

[Bob La Londe]

I am thinking I'll go with the PC in one of the cabinets, and just use a monitor and keyboard swingarm of some kind. Maybe fabricate a pendant mount to hang on the swing arm. I am hoping I can swing the monitor all the way around next to the cabinets and out of the way that way, but move it out front when I need it. I have to mull over that idea some more.

Since I moved the mill over next to my office I am thinking I'll add a 6" duct to one of the muffin fans to blow cold air from the office into the machine cabinets. This makes me a little less apprehensive about putting the control PC in the machine cabinets. My shop is not air conditioned and I am in southwest Arizona.

[Bob La Londe]

I was looking at the mill this morning with an eye towards keeping the cables from the motirs and encoders as short as possible. I noticed there is a long thin enclosure on the back of the table. Is that just limit sensors like the ones on the head?

[Bob La Londe]

I've been making stuff for other folks lately and haven't had time to play with the Hurco. Finally got back to it again for a little while today. Figured I'ld get the power supply for the servos dialed in. I thought the transformer was bad at first. I hooked it up, pulled two wraps off the LV side and got zero volts. No smell. No heat. So I knew it wasn't shorted out, but dang. I put the meter to the HV side and got 230. Stranger and stranger. Shut it down pulled the power from it, and carried it over to my work bench for a look see.

Cold solder joint on one of the HV terminals gave up the ghost. I resoldered both of them, and checked it again. WE HAVE POWER. It was a little high so I removed one more wrap.

I was shooting for 57 volts on the LV side. I guess this will have to do.

Finally found what should be the simplest way to rewrap my transformer also. 3M sells "Varnished Cambric" tape by the roll in both adhesive and non adhesive.

[Jackal66]

Bob,

It looks like you have it going on!


Once you start you can't stop.

It was hard for me to stop working on the retrofit to do my paying jobs.


JAckal

[Bob La Londe]

Soon I will have no excuses for proceeding with this retrofit. I finally ordered the last thing I think I need to complete the basic build. I went with US Digital E6 1000PPR encoders. I'm a little concerned with the cable length, but Marcus at GeckDrive doesn't think it will be a big issue. He thinks USD is pretty conservative with their length limitations. I ordered 14' cables figuring if I need the length its better than splicing, and knowing that its easier to shorten a cable than to lengthen it. Z should easily be less than the 6' USD reccomends, but X may be close to 12' at full right movement of the table.

E6-1000-500-NE-S-H-D-B
US Digital | Products » E6 Optical Kit Encoder

I also ordered some heat sink. I was just going to make some on one of the mini mills, but this one isn't much more than the cost of the raw mill rolled aluminum. I bought two pieces. One has more than enough surface area for all three gecko drives, but I figured it would be nice to plan space for more stuff if I decided to make this into a 4 or 5 axis machine in the future.

10" Long Aluminum Heatsink Audio Amp - Transistor and Diode HSG-0710 | eBay

I'ld like to get a VFD rated for the full 5HP of the spindle motor when run on single phase, but as long as I keep my power loads under 3HP I should be fine with the current VFD in the machine. Drives Warehouse has a nice one by Speedstar rated for a full 5HP with only single phase input, but I spent my toy budget for the next couple months already.

[Bob La Londe]

Finally did some actual work towards restarting the machine today. As you may recall this mill has 2 separate 3 phase motors inside the spindle motor housing. One is a straight 3 phase 5 HP motor labeled to run from 3hz to 120hz. The other is a fan motor intended to run on 60hz continuous to cool the other motor. I don't know for sure what its horsepower rating is, but I can't imagine it needs to be more than 1/2 hp since all it does is spin a fan.

When I originally opened the motor case to figure out why there were so many wires sticking out I found that a couple blades had broken off the fan. I still haven't gotten around to ordering another fan blade so for the time being I broke the opposite two blades off the fan so it wouldn't be grossly out of balance.

As mentioned the fan motor is also 3 phase. I do not have 3 phase power in my work shop so I bought a used KB Power VFD off of Ebay. Its capable of 0-120 hz and is rated for 1/2 HP. I have a jumper across the start pins and its wired for now directly to my mains into the cabinet. I set minimum frequency to 24 hz (the highest minimum would set to) and added the speed control 5K linear POT. Its jumper selected to 60HZ max so all should be good. I could probably just use resistors since its always going to be run at 60HZ, but I had the POT already.

I spun the POT to MAX and turned on the cabinet mains switch. NOTHING. Good thing too. LOL. I forgot to connect the other end of the leads to the motor. They could have been touching and things would have gotten exciting. Powered it down. Waited for the lights to go out, and then hooked up the fan motor.

Spin the POT to MAX, flip on the cabinet mains, and WHIRRRRRRRRRRRRRRRRR. Sounds good and no odd whine, whir, or vibration that would indicate a gross out of balance. I'll probably run it with that fan until I have the machine fully operational. Then it will be time to buy one or make one. I can see me needing it since the spindle motor is rated down to 3hz and 96 RPM. If I put a good tach or encoder on it that speed could be used for rigid tapping.

http://www.youtube.com/watch?v=SNXvepEVC0Y]IMAG0048.AVI - YouTube

I hope its not that loud after I put the motor cover back on. Anyway, for now I have it wired to be on any time the mains power is on, but I think I will remove the start jumper and hook it to a relay so that it only turns it on when MACH has an M3 spindle command in operation. Maybe set a decel and a delay so it stays on a few seconds after an M5 is processed.

[Bob La Londe]

Just getting the hardware layed out in the control cabinet now. That heat sink is mounted on an angle bracket which hangs it about 5 inches out from the back plate. The backs of the servo drivers are liberally coated with heat sink compound and screwed to the heat sink. They are deliberately spaced that low on the heat sink to give room for a small screw driver to adjust the pots on the heat sinks, but high enough to put wires in the screw terminals without removing them from the servo drivers.

I can remove that whole assembly with just two screws so I can get it out of the way to drill and tap standof holes, and exhaust and intake fan holes etc without getting any metal chips in the electronics.

There will be an exhaust fan at the back of the cabinet directly in line with the fins on the heat sink. There will be an intake fan in the back at the top.

I tried to leave room to mount a second heat sink in line with the first in case I decide to add additonal axis controls (servo drivers) to the machine in the future. I just checked and in order to clear the fan I will have to move the first one over to the right about an inch. Fortunately I have plenty of room to do so. It will make that first servo driver a little tight to get a screw driver on, but there will be room.

[Bob La Londe]

Every little thing on this machine seems to take forever. All I accomplished today was to mount he C23 breakout board and Smoothstepper on standoffs on the back board in the cabinet, and mount one of the two cooling fans the cabinet will receive.

I drilled and tapped the backboard for the standoffs. Then I studied the back of the c23 circuit boards. Its got a coating on it, but there are a couple traces on the back that are awfully close to the mounting holes. Off to the store for some nylon washers. I put nylon washers on both the front and the back of the board on every mounting screw to prevent any issues with possible shorting to hardware.

I reversed two of the standoffs that came with the SmoothStepper, cut off a couple screws, and used them to sort of stabilize that edge of the board to the C23 board. The other side was two far from the back board to mount so I used a couple nylon spacers with a couple small flat washers behind those to secure that edge of the SS level with the edge secured to the C23. I drilled and tapped holes in the backboard for those too.

Then I took everything out while I used a hole saw to cut a hole for the exhaust fan. The first pilot drill snapped off when I bound the saw. The second one was dead soft and kept bending. Finally a thrid pilot drill seemed to be up to the task. I also fried got my cordless drill really hot. It won't switch back into high gear anymore. Still works fine in low gear though.

Drilling and tapping the cabinet to mount the fan went really easily, but I couldn't find the plug that connects to the electrical pins on the fan. So before I could mount it I soldered an appliance cord directly to the pins, and slipped a piece of shrink tubing over each connection. Every time I kill a power tool that isn't worth rebuilding (for one reason or another) I strip a few parts out of it. Any good bearings, brushes, switches, and the power cord. These things have allowed me to make quick repairs many times. In this case I have a nice appliance cord on this fan now.

I just put everything back in. Don't think I'll take it out again though. I'll just tape a plastic drop cloth over it when I am drilling and tapping for other things.

I guess its about time to clean all the junk out of the bottom of the cabinet and move it over to a tool cart.

[Bob La Londe]

I shifted the heatsink and controllers to the left closer to the fan. I started worrying about where and how I would be routing wires between the cabinets and trying to limit induced noise. All wire pairs are twisted, but that may not be enough so I moved a few things around. I'ld have been further along, but I hooked up my bridge rectifier wrong and let all the magic smoke out of it.

POOF! BWOKEN!

The day job has picked up so even though a replacement rectifier arrived last week I didn't get around to hooking it up until today. I think the forward voltage drop is greater through the recitifier than anticipated. My math says I should have about 78-79 no load voltage off the cap, but I have 75.01 VDC. I don't think its really critical unless I try to get 300ipm rapids with lots of reversals and a heavy load on the table. Hurco only speced the machine originally for 250ipm (Section 1, Page 1-3, Table 1-1). I was thinking I'ld start at 100 and work up from there. I am going to have 4 vises on the table most of the time so I can setup multiple parts or single long parts. The table won't be light, but nowhere near the 500 lbs Hurco speced in the same table.

As soon as my cap finishes discharging (its been atleast 45 minutes and it just dipped below 40 volts) I'll mount the rectifier to the backboard and snap a couple pictures. I was going to ignore the suggestion for a dump circuit, but I can see why Gecko Drive reccomends it. I think that long discharge time has convinced me.