Picking Power Supply help

Hey Guys

I am looking for some advice on picking a power supply for my delta project. I have done a lot of reading online but I am very confused when it comes to electronics.

When It comes to picking a power supply I was thinking about using a 12v 33A 400W PSU as per a delta machine I have currently.

However in my limited knowledge of electronics I thought that the PSU must at least equal the demand of the parts or it will fail. I have been counting up the demand of the parts I intend to use on the project and they exceed the 400W supply.

Parts I intend to use:

Steppers - 17HM19-1684S x4 - 80W (20W each)
Hot end either 25W or 35W
LED's - 60W <- this value based off an ebay lisitng for LED strips detailing PSU required per required length. I intend to put around 700mm on LED's on each tower.

Now for the confusing bit I dont understand - the heated bed. I intend to use an MKS SBASE board as I like the functionality of the colour touch screen they have. Also I spoke to a guy who uses these a few weeks ago at the TCT show in Birmingham and he highly recommended the board. Its heated bed MOSFET is rated to 300W so I assume my heated bed silicone pad must be under that to not damage the board.

I have found a heater pad on aliexpress which is 220V 250W 1.14A. Does this mean that it will use 250W of my PSU as that would be a running total of 415W and therefore too much for my 400W PSU or as its rated for 220V and Im running it through the board will it only be a fraction of that? If its the later will this pad even be suitable?

I came across a blog by David Crocker (DC42) that details his delta build and he confused me even more as he's using a 350W heated bed silicone pad but only powering his machine with a 12V 100W PSU!! (This is pre update as he's now running 24V electronics)

Any help would be greatly appreciated guys.

Thanks.

Hello, would you like to tell me what's your hot bed's power?

Quote
Mils24

Now for the confusing bit I dont understand - the heated bed. I intend to use an MKS SBASE board as I like the functionality of the colour touch screen they have. Also I spoke to a guy who uses these a few weeks ago at the TCT show in Birmingham and he highly recommended the board. Its heated bed MOSFET is rated to 300W so I assume my heated bed silicone pad must be under that to not damage the board.

I have found a heater pad on aliexpress which is 220V 250W 1.14A. Does this mean that it will use 250W of my PSU as that would be a running total of 415W and therefore too much for my 400W PSU or as its rated for 220V and Im running it through the board will it only be a fraction of that? If its the later will this pad even be suitable?

If using a 220V heated bed, then it doesn't draw its power from the PSU, it draws the power from the mains connection. All the PSU has to do is turn on a relay / SSR via the control board.

The components you have chosen will draw at a maximum about 200W, which should be fine for that PSU.

If, however, you were using a 12V heated bed then you might be getting up towards the limits of your PSU.

Hello!
On the MKS SBASE, the maximum input current of motor and heating rods is 15A, and max input current of hot bed is 30A. But the only worry is that the current is almost to the limit, I fear that it is easy to burn out. I suggest that the hot bed should be connected to an external large MOS module, like TB6600.

I went with a corsair RM 550x. Which was admittedly pretty overkill. But beautiful PSU. Full modular so I carved up the motherboard plug to make a jumper plug for the always on, and carved up the 8 pin cpu cable which provided 4 18 gage 12v leads capable I believe of delivering 40 amps on that 12v rail total. And presumably another 40 amps on the other 12v pcie / cpu header.

Beautiful PS, fan never even kicks on running the printer.

It was expensive, but my philosophy from computers that carries over, is never ever cheap out on power supplies.

Edited 2 time(s). Last edit at 10/25/2016 08:20PM by feistylemur.

Yeah mains heated bed is the way to go plenty of power but relatively low current so sensible sized wiring can be used. Plus all the high current required for low voltage heated beds is kept off your controller board. I'm running my 24v large delta on a laptop psu, the 500w heated bed is run by an ssr from the mains.

Make sure to use a gfid/rcd and ensure the frame, bed etc.. Are all earthed in case the silicone heater fails.

You said you were going to use 700mm of LED's per tower? Have you powered them up? You might not need that many, I used about 5 of the LED's on the x and y towers, if you put them on the z tower they shine in your face. I also put some on the top front horizontal facing downwards.

Good luck with the build post some images it'll be good to see.

Edited 1 time(s). Last edit at 10/28/2016 09:55AM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions