dc amps vs ac amps

[Lee Roberts]

While what you are proposing CM will work, good electrical working practice is to independently feed high current circuits directly from the power supply to minimise interaction between circuits.

Ok thank you, i just wanted to now and understand/learn rather then just be told :).

You say your power supplies are rated at 7A typical, 9A peak and you are running them in parallel. What supplies are they and are they linear or switched mode regulated or unregulated?

They are from MCP, PS407:

The PS Power supplies are available as 40V and are non regulated switch mode power supply specificaly made for use with our range of stepper and servo drivers.

Supply Voltage: 180 to 250V AC


Output Voltage:

• PS407 - 40V DC at 0A and 38V DC at 7A

Output Power

• PS407 - 260W (Continuous)

Make sure the wire connecting the supplies together is heavier than the motor wire - best practice is to wire both supplies to a common connector block from where the motor wiring is taken (in high current systems a copper bar (busbar) is even better). Failing this, use 2 or 3 pieces in parallel.

I will look at how i would like to go about connecting the supplies together and get back to you with what i propose doing, could i use copper clad board as an option? reson being i'v got some of the green screw terminals you find on the BOB boards i could solder in.

I would argue that fuses are essential. If they 'go wrong' and are correctly sized then its a sign there is a problem somewhere... better to blow a fuse than fry a driver...

I couldnt agree more, while the drivers dont cost a fortune, it would be much more inconvenient replacing one of them, then a fuse located on a front panel deisgned with easy access in mind ;).

I'v just found this as well: http://www.mycncuk.com/pdf/wiring.pdf

CM

[irving2008]

Ok thank you, i just wanted to now and understand/learn rather then just be told :).

No problem, happy to help

They are from MCP, PS407:


I will look at how i would like to go about connecting the supplies together and get back to you with what i propose doing, could i use copper clad board as an option? reson being i'v got some of the green screw terminals you find on the BOB boards i could solder in.

I'd be careful of those green things, most of the 0.1"/2.5mm spacing found on BOBs are only 1 or 3A rated. You'd need the bigger 0.2"/5mm spaced versions which are 7 or 10A rated

What I've done in the past for some high power radio gear is taken a length of brass bar, 8mm x 4mm, drilled the ends 4mm clear to fit the PSU terminals (3.2 or 3.6mm screw lugs) and then drilled/tapped 3mm (or similar sized BA) take off points for ring terminals along the bar (use brass screws)

I couldnt agree more, while the drivers dont cost a fortune, it would be much more inconvenient replacing one of them, then a fuse located on a front panel deisgned with easy access in mind ;).

I'v just found this as well: http://www.mycncuk.com/pdf/wiring.pdf

CM

Yes I've seen that diagram before... note its a connection diagram not a wiring layout diagram - it shows what connects to what, not how to do it properly.