60-70v unregulated power supply recommendations

[Agathon]

I'm running 3 Leadshine AM822 drivers with 2 at more or less their maximum current (5.86A RMS) and my 36v switch-mode power supply just isn't up to it.

I've been recommended to buy an unregulated supply of around 60-70v. I'm guessing that a 10A supply will be enough to drive all three motors (the Z axis requires very little power). Can anyone recommend a supplier or a method of construction.

While I currently have just 3 axes but might want to increase to 5 although the 4th and 5th will need lower power motors.

[Clive S]

I'm running 3 Leadshine AM822 drivers with 2 at more or less their maximum current (5.86A RMS) and my 36v switch-mode power supply just isn't up to it.

I've been recommended to buy an unregulated supply of around 60-70v. I'm guessing that a 10A supply will be enough to drive all three motors (the Z axis requires very little power). Can anyone recommend a supplier or a method of construction.

While I currently have just 3 axes but might want to increase to 5 although the 4th and 5th will need lower power motors.

Ok I am in Spain after a bit of vino But here is a link http://www.zappautomation.co.uk/ps80...er-supply.html but you could build your own for nearly half the price with bits from Rapid on line. https://www.rapidonline.com/electronic-components

[Agathon]

Thanks Clive - I bet it's hot there!

I've seen those rectifier/smoothing capacitor boards on most home-built PSUs are they available from eBay and Aliexpress? Not quite sure what to search for.

Enjoy you holiday!

David

[Agathon]

Having thought about it, I only need to run 2 of the AM822s from a 60-72v PSU. If they are set at their maximum current what sort of VA do I need from the transformer? I'm guessing this will partly depend on the specification of the smoothing capacitors.

[Clive S]

Thanks Clive - I bet it's hot there!

I've seen those rectifier/smoothing capacitor boards on most home-built PSUs are they available from eBay and Aliexpress? Not quite sure what to search for.

Enjoy you holiday!

David

The boards I think you are referring to are not suitable as they have very small caps on them.

[routercnc]

Have a look at Joe's recent build:
http://www.mycncuk.com/threads/4513-...-router/page19
post #373 onwards

And mine from a while ago:
http://www.mycncuk.com/threads/6988-routercnc_MK3/page3

[Clive S]

Having thought about it, I only need to run 2 of the AM822s from a 60-72v PSU. If they are set at their maximum current what sort of VA do I need from the transformer? I'm guessing this will partly depend on the specification of the smoothing capacitors.

Some links here.
https://www.rapidonline.com/50a-brid...al-case-519318

https://www.rapidonline.com/samwha-h...acitor-11-3121

https://www.rapidonline.com/lcr-ep08...-clamp-11-3004

This has secondary of 25-25v some people like 24 - 24V
https://www.rapidonline.com/vigortro...-x-25v-88-0005

And a vid by Joe. He used 4 caps but three is fine.
https://www.youtube.com/watch?v=4OoQQg76ar4
https://www.youtube.com/watch?v=WISDqx-e23M

[Agathon]

Many thanks.

What do you think about power output. I'm running the 2 AM822s at 5.8A RMS (actually, I think that once I have the interface cable I'll programme the drives to 5.5A RMS (2.8 x 1.96) - but that's splitting hairs) so that's total RMS current of 11.6A. The AM822 manual says that 50-70% of the motor current will be sufficient.

So 2 x 5.5A = 11.0A. 50-70% = 5.5-7.7A x 70v = 385-539VA. So a 500VA transformer should be OK?

Does that sound right or should I be working with the AC output voltage of 50v?

I see that Joe used a massive 750VA transformer.

[Clive S]

Is there a reason you are using just two motors like it is a lathe?

I run 4 nema 23 on my router without problems and 3 on the mill both with 500va transformers the next one up is 625va.

Remember that the motors rarely all run at peak current together.

[GND]

And your calculations should use the AC rather than the DC voltage as the factor into the VA rating - so your figures immediately fall by a factor of 1.4! The DC output is essentially the peak value of the AC voltage, having been rectified and filtered, whereas the VA rating is RMS.

Hope that helps!
Graeme