[pippin88]

I'm rebuilding a small CNC lathe and I've got a fairly solid servo to use for the spindle.

It's a Global Motion Technology DC Brushed Servo
72VDC
7.8 Amp continuous
40 Amp peak
4500 RPM ±10 % AT 72V
2750 RPM ±10 % AT 50V
http://www.motiontek.ca/pdf/SM34840.pdf

I'll be running it on a Gecko G320X driver (Max 80VDC, Max 20Amps current) http://www.geckodrive.com/gecko/imag...0Formatted.pdf

Can anyone recommend where to get a power supply?
Ideally I'd like 72V for best performance, but could cope with 48V plus I guess.
My understanding is that a simple linear (not switch mode) power supply is best as they tolerate transient peak current draw better.
Or is there something I can do like chain server power supplies (I've seen people do this for battery charging).

I'm located in Australia but happy to build from abroad.

[jalessi]

Pippin88,

Antek has what you are looking for.

Power Supplies - 1500W - AnTek Products Corp

They also have a eBay store:

items in store on eBay!

Jeff...

[Al_The_Man]

I second the Antek source, also you can buy the individual parts for a cheaper build.
There are only three basic components in a linear supply, Tfmr, Bridge & Capacitor.
Remember the AC secondary required is 0.7 x the required DC.
Al.

[pippin88]

Thanks for the input guys. I've contacted them to get some advise re whether 1000W would be enough and shipping.

I think it's probably best for me to buy a prebuilt rather rather than DIY.

[pippin88]

Someone has suggested running 800 - 1000W worth of 72V Switch Mode power supply in Parallel

Such as:
CE approved switch power supply 72v 400w 5.5A S 400 72-in Switching Power Supply from Electrical Equipment & Supplies on Aliexpress.com | Alibaba Group
or
500W 72V 6.9A 220V INPUT Single Output Switching power supply for LED Strip light AC to DC-in Switching Power Supply from Electrical Equipment & Supplies on Aliexpress.com | Alibaba Group

Can anyone comment on this strategy?

[Al_The_Man]

Personally I would never use a SMPS for steppers or servo's, especially running two in parallel, it may turn out to be false economy.
Al.

[pippin88]

Thanks Al. The price difference would not be enough to justify the stuffing around and lower reliability.

I sent Antek an email asking for advice on whether 1000W would be adequate but haven't heard back.

[pippin88]

I've decided to go for toroidal from Antek.

I'm just not 100% sure on sizing, 800 vs 1000 vs 1500 watts.
Probably 67V

Servo takes 72V max. Continuous current 7.8 amps. Peak 40 amps.
Gecko 320x is limited to 20amps peak.
Gecko 320x is setup so continuous current is drawn, when an overload is reached it will then allow up to 20 amps for 1 second. It will then limit back to the continuous current.

An 800W supply gives 11.9amps, so heaps for the continuous draw. I can't find an overload rating / tolerance for toroidal supplies, so I'm unsure if it will tolerate 20amps for 1 second (unlikely this situation will be encountered often).
(If need be the G320x can be limited to continuous current only and it won't be a problem, but I lose a bit of power that way.)

[alan_3301]

not sure about the 1000W supplies (not sure why it would be any different) but...

quoted from their 1500W 70V product description

It can easily handle up to 200% over load for few minutes
It will work continuous without any over heat problem.

[pippin88]

Alan, thanks heaps for finding that. I'd googled for ages and scoured antek's site for spec sheets, but I hadn't gone back to the 1500W supplies.

I've gone for the 800w 70v supply