Fully supported linear bearings - Radial squareness

[Clive S]

This is the motor kit I am considering now: http://www.ebay.com.au/itm/171937212...84.m1436.l2649

Kits are hardly ever a good idea as they are never matched. You need motors with very low inductance and drives that can handle 68V volts to get the best out of them. Go for a toroidal type power supply rather than a switch mode type.

Before you start spending hard earned cash it might be better to do some research as these parts can make all the difference between a good machine and a duff.

[Slixxor]

Kits are hardly ever a good idea as they are never matched. You need motors with very low inductance and drives that can handle 68V volts to get the best out of them. Go for a toroidal type power supply rather than a switch mode type.

Before you start spending hard earned cash it might be better to do some research as these parts can make all the difference between a good machine and a duff.

Thanks Clive, I dont have an issue with switchmode PSU's. As a worst case i'll make a quick back EMF circuit and put some filtering caps across the bridge.

You are dead right about the affect of inductance on supply voltage, especially at higher RPMs. So I have found a reasonably priced torquey Nema23 model

http://www.ebay.com.au/itm/3PCS-3Nm-...EAAOSw37tV85jU

inductance is 3.8mH - The lowest i've seen on ebay in that size.

What is everyones thought on this motor?

[Neale]

Thanks Clive, I dont have an issue with switchmode PSU's. As a worst case i'll make a quick back EMF circuit and put some filtering caps across the bridge.

Not quite sure whether you mean you'll use a switch-mode supply or not. However, the linear supply is often better to drive steppers; the duty cycle of the load is relatively low, even though the peak demand can be high. With a SMPS, you need to rate it for max peak load to avoid it going into current-limiting where a linear supply can handle the peaks even if rated for average load. But then, you can buy cheap SMPS from China...