What power supply for my bench top cnc machine

[xcphil]

I have recently purchased a benchtop CNC machine which did not come with a power supply. I saw it working when I bought it so that isn't a problem, but I have done two major mistakes.

1. Lost the paper printouts explaining which power suply i need and:
2. Don't have the gentlemans phone number from where I purchased it from.

I do how ever have all the little voltages and currents needed for the motors and need someone to push me in the right direction as to what power supply to link it up to.

It has a rather large capacitor which the power supply links to and i have shown some pictures below which may be of interest.

If anyone can tell me what voltage and current supply to get then I would be very grateful.

Oh, at the moment its a 3 axis mill but has a board for a 4th motor and i have intentions to turn it into a 4th axis machine at a later date, if that has any implications please do say.

[jerber]

I have no knowledge of your machine but it depends on what your driverboard can handle.
The 50v capacitor indicates it's around 42v max.

You should be ok with a 24-40V 10A supply.
If your spindle uses the same supply then you need more amps.
But you can test it first on 12v (car battery) and measure the amps.

You can use a switched powersupply with that capicitor.

I see no 5v regulator on the last picture of your driver board.
So you might need a separate 5v source as well.

Hope it helps.

Jeroen

[xcphil]

thanks for that. It's a first step i think.

When I saw it working the guy was actually using a car battery charger and there was no aux 5v supply.

The spindle is run off of 240v mains so it is external to the motors.

I hope that helps.

He did say that it would be good to buy a bigger capacitor, as it wouldn't hum as much, is that right?

[jerber]

I use 20000 uF on a switching 26V/10A supply and have no humming other then from the steppers.

What are voltage ratings of the capacitors of the driver board ?
Is there something printed near the power terminals on the pcb ?
Is it possible to post a bigger/more detailed pictures of the driverboard ?


Jeroen

[xcphil]

It doesnt say which make it is on the top or bottom of the PCD. I've taken some pics at a low resolution for you to look at.

If you would like to look at some high res ones I could always email them to you to look at if thats alright.

The ratings of the capacitors behind each heatsink on the board are 220uF and 50V

Please forgive my ignorance in electronics, my strengths lie in 3D mechanical solid modelling and kinematics, although I have been known to change the odd plug on the kettle here and there

[joecnc2006]

isn't it a Xylotex board?

http://www.xylotex.com/4axBoard.htm#4axis

http://www.xylotex.com/XS3525V400.pdf

all the info you need should be there.

joe

[bkukowski]

It looks almost exactly like a xylotex board. (maybe a different revision of it) http://www.xylotex.com/4axBoard.htm#4axis
I would contact them.

[xcphil]

it is a xylotex board. Just had a look at the sales doc which gives the basic run down and it says it has a xylotex board.

I'm going to run through the PDF and if i have any Q's I'll let you know.

Cheers guys. It's amazing what you dont noticce when its under your nose

[sdantonio]

As joe said, it looks a lot like a xylotex board in which case there are your specs.

The XS-3525/8S-4 Stepper Motor Driver Board (Ver 4.00) $175.00

The Perfect Choice For Your Sherline or Taig Four Axis CNC Retrofit
# Four axis bipolar drive
# ±2.5 Amp/Phase PWM controlled drives
# up to 35 Volt (w/BEMF)
# FULL, HALF, QUARTER, & EIGHTH step/Full Step
# Built-in DC-DC Converter for 5 Volt Logic
# Filtered and Buffered STEP & DIR Signals
# Built-in Break-out:Screw Terminals for Unused Parallel Port I/O
# Synchronous Rectification
# Internal UVLO and Thermal Shutdown circuitry
# Easy connect for most popular Step/Direction control software
# Small Size: 5.65" X 2.85"
# Use with Mach2 (WinXP or Win2K) or TurboCNC (DOS)

The a3977 chip they use are restricted to 35VDC or less. Xylotex sells a power supply that is rated at :

24VDC/4.5A Power Supply (3.86"W X 7.81"L X 1.66" H) with 120VAC Power Cord, and 24VDC Pigtail

2.3" X 2.3" X 1" 24VDC Fan with 2-pin Molex conenctor

The Combo for $50.00

Steven