Emco PC120 Turn

Quote:

---

Originally Posted by Chaz

My best bet is probably something like this.

http://www.zappautomation.co.uk/elec...-supply-7.html

Move the drive power to this, leave the 24V supply to do the logic stuff only.

---

http://www.zappautomation.co.uk/elec...-supplies.html

edit you beat me to it or build one

Quote:

---

Originally Posted by Clive S

Also you don't say what PS you are using switch mode are not good for steppers.

---

Why ?

Quote:

---

Originally Posted by cropwell

Why ?

---

I googled it.

This might help answer - http://www.cnczone.com/forums/genera...-steppers.html

This driver is a three phase driver (For Three phase stepper motors) Looking at the part number it implies that the maximum voltage is 80V DC and the current is 6.0 A.
3 = three phase
M = Motor driver
8 = Max voltage (80V)
60 = 6.0 A maximum current.

This is the typical makeup of the part numbers.

Quote:

---

Originally Posted by Chaz

Ye, possibly around 50V.

They did work well before the previous set of PSUs died. The current PSU is one of them el cheapo ebay ones, I presume they are SMPS.

Id like to sell the lathe but need it to be 100% reliable before I do. Any suggestions on what PSU would suit if I was just going to upgrade this? Lets assume 36 or 48V max.

lll take a look at the AM882 anyways.

Thanks

---

Quote:

---

Originally Posted by Gary

This driver is a three phase driver (For Three phase stepper motors) Looking at the part number it implies that the maximum voltage is 80V DC and the current is 6.0 A.
3 = three phase
M = Motor driver
8 = Max voltage (80V)
60 = 6.0 A maximum current.

This is the typical makeup of the part numbers.

---

Thanks Gary. I looked on your and a few other sites to try and find who makes this driver, but no such luck.

I also know little about the motors, it was all fit by someone before I bought the lathe. Not a bad job overall. The PSUs that failed looked to be fairly high end things, but voltage is only 24V.

Using that search phrase, Ive found this, similar.

http://www.ebay.co.uk/itm/CNC-3-Phas...p2047675.l2557

https://www.dhgate.com/product/new-c...126671364.html

I might be able to find the manufacturer spec eventually :hurt:

Bingo, I think.

http://www.jmc-driver.com/h-pd-155.h...M860&_pp=0_334

So the 6 is RMA current and its up to 80V DC.

Quote:

---

Originally Posted by Chaz

Bingo, I think.

http://www.jmc-driver.com/h-pd-155.h...M860&_pp=0_334

---

Quote:

---

Originally Posted by Gary

So the 6 is RMA current and its up to 80V DC.

---

RMS ? ;p

Yes RMS, have big manly fingers and the a and the s are quite close.

Quote:

---

Originally Posted by Gary

Yes RMS, have big manly fingers and the a and the s are quite close.

---

Plus, you deal with RMA stuff, so it could have been a finger memory thing. I do it often myself.

Ill also check the current setting - may bump this up (if not max already) and see if its makes the response better.

Quote:

---

Originally Posted by Chaz

So, since I have changed my PSU, my steppers dont seem to want to perform. It could be a cheap PSU however not sure.

If I am going to add in another PSU, should I try and increase the voltage? I cant see the exact number, I cant find these drives anywhere - but lets assume it will take 48V DC. I also need to check if the current settings are correct for the specific voltage. Currently everything runs off a 24V 10A supply.

Would it be 'good practice' to try and get the voltage as high as possible?

---

Have you tried running the lathe with a voltmeter (an oscilloscope would be better) on the powersupply to see how it's handling the load?

If you were getting good enough performance with 24V, I probably wouldn't be inclined to bump it up that much. I'd probably aim around 30-40V, but it would really depend on what the motors could handle. Remember higher voltage just means better performance at speed. At low speed it won't make much, if any difference.

Quote:

---

Originally Posted by m_c

Have you tried running the lathe with a voltmeter (an oscilloscope would be better) on the powersupply to see how it's handling the load?

If you were getting good enough performance with 24V, I probably wouldn't be inclined to bump it up that much. I'd probably aim around 30-40V, but it would really depend on what the motors could handle. Remember higher voltage just means better performance at speed. At low speed it won't make much, if any difference.

---

Nope, but was going to do that.

The current ability of the PSU is 10A (in theory), the same as it replaces. Its Ok with slow speed, its when I try to rapid that it tends to struggle. Ill take a closer look this weekend.

Interesting, no vault drop. The drives are actually 3M860.

I tried to set the current up - no change. Ive then ensure all the bits are well lubricated (the pump hasnt been run for a while), no real improvement.

Set the max speed down, seems OK at 700 although it should be able to do 2000 I think from the spec / manual.

Perhaps the lubrication is not getting to the dovetail / sliding area, difficult to get there without removing a lot of stuff. That said, it should be adjustable, will do some further research, perhaps the motors are stalling due to this.

I wonder if there's something else damaged. It's a bit suspicious that everything worked before on 24V, yet now it doesn't.

Without an oscilloscope, or swapping parts, it's all pretty much guesswork. The fact the relay board got damaged before, possibly suggests the BOB might also of been damaged, and is something that only shows up at higher step rates.

Quote:

---

Originally Posted by m_c

I wonder if there's something else damaged. It's a bit suspicious that everything worked before on 24V, yet now it doesn't.

Without an oscilloscope, or swapping parts, it's all pretty much guesswork. The fact the relay board got damaged before, possibly suggests the BOB might also of been damaged, and is something that only shows up at higher step rates.

---

Perhaps however Ive since swapped it.

Im tempted to put in another PSU but not worth spending on. I seem recall that I was pretty much on max before. The motors look fairly old, I cant find a spec for them, perhaps something else that wasnt done correctly doing the retrofit.

So, Berger Stepper motor.

4.4A, is that 50V DC?

https://c1.staticflickr.com/5/4399/3...60d4766e_k.jpg

Found this - http://www.equitecnica.com.ar/files/...225212_8_9.pdf they only list 1 motor that does 4.4A, the torque matches. Max Supply Voltage is 92V according to this .... wonder if its correct. Might explain why the motor doesnt perform running 24 Volts.

Noted that the drive can do a much better microstep rate. I wonder if the motor would support that and give me any better performance?

Does anyone know if there are 'charge pumps' for sale as a standalone kit? I cant find any and dont want to buy a BOB with it for £80 if I can avoid it. I realise its a simple circuit but dont have the time to build something at this stage.