[R L Harris]

Hi to All Iam Rusty L Harris here is start of My build post!
Attached are photos of frame components and shop.
Iam currently painting the frame components as you see!

[R L Harris]

Finshed painting legs and 8 braces tomorrow start painting table!
Ahren's Extended linear carriages arrived today

[R L Harris]

Finished Painting and reassemabled table

[TarHeelTom]

The table looks good so far.

Tom

[R L Harris]

I work for KC Store Fixtures as Design Engineer used thier metal fab shop to cut and weld the components!

[TarHeelTom]

Nice to have resources !

Tom

[ahren]

Just stumbled across your build -- looks really good, and I envy your steel-working prowess! I'll add your build log to the list on the cncrouterparts website since you're using our carriages. Are you planning on using our rack and pinion drives, or are you going to build your own setup?

Ahren
www.cncrouterparts.com

[R L Harris]

Just stumbled across your build -- looks really good, and I envy your steel-working prowess! I'll add your build log to the list on the cncrouterparts website since you're using our carriages. Are you planning on using our rack and pinion drives, or are you going to build your own setup?

Ahren
www.cncrouterparts.com

Hi Ahren plan on ordering them next paycheck!

[R L Harris]

Ok Gear Racks are here they were waiting between screen door and door
when got home from work - (Hell)!
Now need to run bye Metal Supply get piece aluminum bar so I can make
some clamps to attach them with!

[CarveOne]

Ok Gear Racks are here they were waiting between screen door and door
when got home from work - (Hell)!
Now need to run bye Metal Supply get piece aluminum bar so I can make
some clamps to attach them with!

Don't you just love it when they do something like that. I came home one day a few years ago to find a $400 R/C model airplane kit I ordered laying across a row of mail boxes next to the highway. They didn't even leave it on the front porch where it could be semi-out-of-sight from the highway traffic.

CarveOne

[R L Harris]

Don't you just love it when they do something like that. I came home one day a few years ago to find a $400 R/C model airplane kit I ordered laying across a row of mail boxes next to the highway. They didn't even leave it on the front porch where it could be semi-out-of-sight from the highway traffic.

CarveOne

Thing is that Instructions on UPS Label said in plain english
to leave with neigbor George @ 1528 who is always home
he is retired!

[absolutepoker01]

Hi folks, hey Carve, where did you get the 72 V psu, i was checking Kelings site and i didnt found one, the one with more volts was a 48, also which is the amperage of that 72V psu?

[CarveOne]

Hi folks, hey Carve, where did you get the 72 V psu, i was checking Kelings site and i didnt found one, the one with more volts was a 48, also which is the amperage of that 72V psu?

The one I am using is this one:

KL- 7220 Specification: $189/pcs
Unregulated Power Supply 1440W, 72VDC/20A ,120VAC or
230VAC

It actually has two unregulated outputs of 72vdc at 10 amps each. I just wired two stepper motors to each output.

CarveOne

[absolutepoker01]

Oh yeah i saw that ones, but they are not switching power supplies, they are unregualted, is there more risk for burning the driver or something like, or is basically the same thing? Has it worked just fine for you, havent had any trouble?

[CarveOne]

Oh yeah i saw that ones, but they are not switching power supplies, they are unregualted, is there more risk for burning the driver or something like, or is basically the same thing? Has it worked just fine for you, havent had any trouble?

You don't need a switching power supply for running stepper motors. The voltage is 72vdc unloaded. It will drop at a predictable rate as the load current goes up. At full load the output voltage is around 55vdc as I recall. The specifications for one of the other Keling PSU models has a chart showing this. If you find a 72vdc switching PSU with 20 amps output you will pay a few thousand dollars for a new one.

The Gecko G203V driver has an input rating of 80vdc. 72vdc is low enough to allow margin for back EMF. Keling's 82vdc power supply is too high.

If you are using some other vendor's driver with a lower input voltage limit you may not be able to use the 72vdc power supply, and should use Keling's 65vdc or 48vdc power supply instead. You will get more torque and speed out of a stepper motor if you use the highest voltage that is safe for your particular driver.

CarveOne

[TarHeelTom]

All you need for steppers is an unregulated power supply.


Tom

[CarveOne]

Oh yeah i saw that ones, but they are not switching power supplies, they are unregualted, is there more risk for burning the driver or something like, or is basically the same thing? Has it worked just fine for you, havent had any trouble?

To answer your other questions, yes, it has been working fine, and there have been no problems. Many others on CNC Zone are using the unregulated power supplies for driving step motors. They are the preferred power supply. Break out boards need regulated PSUs, but they generally have low current requirements.

Regulated power supplies are better for electronic circuitry that have much more critical requirements than these step motors. You can use switching PSUs but the cost is not worth the minor benefits of keeping the voltage a little higher. One way to lower the cost if you really want to use switchers is to buy a lower wattage switching PSU for each step motor. Three (or four) of them is much less expensive than one 72vdc 20 amp PSU because of the more expensive high current components and construction required to manufacture the 20 amp PSU. I wouldn't recommend going this way though.

CarveOne

[absolutepoker01]

OK thanks a lot for sharing the knowledge, so the only advantage of a switching psu against a unregulated is that the switching would not drop the voltage no matter the load that its attached to the end?, isnt there any other advantage, like security issues?

[CarveOne]

OK thanks a lot for sharing the knowledge, so the only advantage of a switching psu against a unregulated is that the switching would not drop the voltage no matter the load that its attached to the end?, isnt there any other advantage, like security issues?

Switching PSUs have a maximum output current rating. Exceeding that load current will usually cause it to go into shutdown mode or blow a fuse.

Unregulated PSUs have a much simpler circuit and fewer components than a switching power supply. Therefore, it has fewer failure modes, and are generally more reliable for the long term than switching PSUs.

CarveOne

[absolutepoker01]

Yes you are right, thanks for the help, i think ill go with the unregulated psu`s, or maybe i can go with two 48 V 12.5 A switching psu and wire them in parallel son i can get 48V 25 A, and its not that expensive, a little more than the unregulated.