Isel CPM 3020 - run with mach3?

**AndrewMawson** · 17-01-2016

Chris,

It depends totally on which drivers you choose. Obviously (hopefully) the PSU voltage cannot be higher than the max spec on the drivers. The higher the voltage the faster rise time the driver can achieve pushing current through the windings of the steppers. If the voltage is too low the driver will give a sluggish performance. Although steppers have a nominal voltage rating they are essentially current operated devices.

**JAZZCNC** · 17-01-2016

Originally Posted by craynerd

Someone suggested 40v but is 36v what I need?

Well if your talking about those DM556 drives I suggested then they are 50V max so I'd be running them around 44-48Vdc provided your using a unregulated Toroidal transformer PSU. 44Vdc being what I'd size for.

I wouldn't run them at 36Vdc

**limpet** · 17-01-2016

To be fair there are lots of possible variables.I reckon that with unregulated PSU`s I would estimate getting smoothed output voltage of about 1.5 times the nominal transformer secondary voltage.
Although I would suggest that you check the load as an output of 44v under no load could easily drop 10 or 15% under load.
On the other hand if your power supply can provide more than 44v under load it could well give over 50v with no load which might give problems.
It all comes down to the resistance in the secondary winding and across the rectifier. As soon as a current is drawn there will be a voltage drop from the no load condition to under load condition.
To be fair there are lots of possible variables, and using a beefy PSU would help.

**Clive S** · 17-01-2016

Limpet First welcome to the forum. Not sure what you are saying here. Have you read the op's problem if you look back he says his power supply is only 24V unregulated and is asking what power supply and drives to get so as to get a decent running system. I think he has been advise to get some digital drives and about 45V unregulated power supply.

**limpet** · 17-01-2016

Originally Posted by Clive S

Limpet First welcome to the forum. Not sure what you are saying here. Have you read the op's problem if you look back he says his power supply is only 24V regulated and is asking what power supply and drives to get so as to get a decent running system. I think he has been advise to get some digital drives and about 45V unregulated power supply.

Hi Clive and thanks for the welcome.
Sorry I could have been clearer.
I was just saying that if he`s creating his own unregulated PSU then a nominal output of 45v with no load could drop to below 40v under load and if he goes for a 45v output under load then the PSU may well give more than 50v without a load which may be too much voltage for his drives. I`m not sure what protection they have.
This may or may not be an issue, but I thought I would just point out the possibility.
I apologise if I`ve clouded the issue, that was not my intention.

I`m no electronics expert but that is my experience with power supplies.

**Steve-m** · 03-08-2017

Thank you may be of interest please pm me with a price, may help me to decide which way to go

**Leadhead** · 03-08-2017

Steve - I would think about £50 for disk, +licence + spiral bound manual. Works very well. You would certainly not want to pay what I paid for it!!!

**dariosh** · 24-06-2018

Hello do you still have kay soft + licence?
Br.Dariosh

**Leadhead** · 24-06-2018

Sorry - Sold some time ago.

**mchipser** · 25-06-2018

Well I thought I was done, but it seems like the microstepping I have set aren't working right.. This is also going to be a pain since the lead screw is in metric, but we use imperial on this side of the pond..

Anywho.. I thought I had everything configured properly, but the x axis keeps skipping a step randomly..