Running 4 axis from a ps806 or sps705 psu

[jonbabbz]

Im shopping for a 68v power supply and am deliberating the ps806 or sps705. Is it possible to run 4 axis from these? The following website says 1-4 axis while zapp says 1-3 axis, I know they have 3 main outputs but can they be used for 4 axis, i.e using one output for a master and slaved axis, or will I have to buy 2 psu's. Also what are the differences between the 2 as the price difference is quite significant? Thanks

http://www.leetro.com/english/sale/73.html

[Jonathan]

Presumably you're using the 3Nm stepper motors which draw 4.2A? I've found them to be OK on one 500VA transformer, but more is more stable.

The PS806 is 500W (500VA strictly) and a linear PSU which for this application is generally considered better than a switching PSU which is what the SPS705 is. In addition the SPS705 is only rated for 340W.

I wouldn't consider either. All you need to find is a suitable transformer, then buy a bridge rectifier, capacitor(s) and solder it all together which is easy enough. If you got the 625VA transformer here that would be good for 4 motors. Shop around, that may not be the cheapest. Anything with that VA rating or above is fine, 24V with two secondary windings in series will get you 48V which is fine, similarly 25V/48V/50V transformers are fine. If you decide to do this I can post the circuit etc.. or you can probably find it as I've posted about this many times before.

[jonbabbz]

i am indeed running the 4.2A motors. If you could post the circuit that would be great, I've searched for it but couldn't find it. Thankyou

[Jonathan]

If you could post the circuit that would be great

Couldn't find it either, so just drew this:


(next time I'll find the mouse..)

Top one if you get 24V or 25V transformer (preferable), lower one if it's 48V or 50V. The capacitor needs to be 10000uF minimum, ideally a bit more so three of these in parallel is good (assuming you get transformer from Rapid, otherwise might be cheaper elsewhere, eBay, Farnell etc). This bridge rectifier is good as it wont need a heatsink. So about £60 in total...

If you got the bits posted to me I'd feel guilty charging more than a fiver to wire it up as it's less than 10 minutes work.

As Jazz just implied, you could use terminal block and crimp connectors instead of soldering.

[Gary]

The PS806 is by far a better solution.
Linear power supplies are much better in handling inrush currents and also the PS806 has a regulated 5V output to power your breakout board.

[JAZZCNC]

The PS806 is by far a better solution.

Not really Gary.!! . . . . To run 4 x 4.2A motors he'll need 2 x PS806 thats £204 plus del For less than 1 PS806 he can build a supply that will easily give what he needs and still have change to buy a small 5V 1A reg supply.!

Inrush is not a problem @ 600Va and easy enough to build an inrush circuit if really needed.! ( Which it won't be in most case's)

[Jonathan]

still have change to buy a small 5V 1A reg supply.!

Don't need much change for that :)

http://www.ebay.co.uk/itm/UK-DC-5V-1A-Switching-Power-Supply-adapter-100-240V-AC-Promotion-/200791372447?pt=UK_Sound_Vision_Other&hash=item2ec 019329f#ht_3691wt_1037

Yep but I find folks under stand better when it's spelled out and the difference known.? He could have been wondering why or how 24V could give him 65+V.?

I guess.

[JAZZCNC]

Don't need much change for that :)

http://www.ebay.co.uk/itm/UK-DC-5V-1A-Switching-Power-Supply-adapter-100-240V-AC-Promotion-/200791372447?pt=UK_Sound_Vision_Other&hash=item2ec 019329f#ht_3691wt_1037

Was thinking something a bit easier and neater than that.!!
http://www.ebay.co.uk/itm/DC-5V-5A-R...item2a1fbcca51

Edit: I've had 2A version of these for £5 before this was just an example.

[Gary]

What is said was the PS806 is a far better solution to the PS705, not just because of the size difference but also because its linear and linear power supplies are far better suited for stepper and servo applications.
The advantage is that the PS806 can handle quick changes in current draw a lot better than the PS705.
Looking at the spec, the PS806 is cutting it very close and ideally you would need about 8-10A of peak current, however I have run 3 X 6.2A motor from one of these with no problem at all and the voltage is still in 60V range.
Next week i will power one up with 4 AM882 and SY60 motors and monitor the current and voltage and report back to you.

[jonbabbz]

I'm fine with building one, but would much rather buy an 'off the shelf' supply than break out the soldering iron tbh. I just wanted to be sure that it would be sufficient to power 4 motors.