Power supply understanding

[smeg up]

Hi,

I am building my own power supply as many others have. So far I think I have got all of the components and their values worked out (apart from the bleed resistor). Just stuck on the final 2 points so if someone could help me out that would be fantastic.

Here is a very crude drawing of what I have so far (didn't put values on or even correct symbols!)

http://www.mycncuk.com/attachment.php?attachmentid=14645&stc=1

My questions are:

1. How do I earth the circuit back to the earthing block?
2. Do I keep all components including the transformer isolated from the chassis and earth just from a single point?

Cheers

Mark

[EddyCurrent]

This looks better.

1. You have the earth correct now. If you want to earth the negative side of the output you can if you want.
2. Yes
Also ideally you want individual fuses on the output for each driver.

[smeg up]

Thanks Eddy.
Hopefully i've added the earthing point in the correct place now?

http://www.mycncuk.com/attachment.php?attachmentid=14655&stc=1

I'm going to put a 230v regulator before the transformer, either an AIO or just the chip on a circuit board with some caps, resistors and a heat sink. The reason I am doing this is because my mains electricity fluctuates. I've took 3 readings at different times and got 235V, 241v, and 248v, so much for the 230v switchover!
With this voltage regulation will I need the drive fuses?
Without you and this forum I would still be trying to work out maximum step motor voltages.
Cheers
Mark

[EddyCurrent]

Thanks Eddy.
Hopefully i've added the earthing point in the correct place now?

Like I said you didn't have to put the neutral to earth, some people do it others don't. In some cases where other equipment is connected you might have to put it to earth to get a common reference but in the case of just using stepper drivers it's not vital.


I'm going to put a 230v regulator before the transformer, either an AIO or just the chip on a circuit board with some caps, resistors and a heat sink. The reason I am doing this is because my mains electricity fluctuates. I've took 3 readings at different times and got 235V, 241v, and 248v, so much for the 230v switchover!

You probably won't need the regulator.


With this voltage regulation will I need the drive fuses?

Yes, the fuses are to protect the circuit from overload.


Without you and this forum I would still be trying to work out maximum step motor voltages.
Cheers, Mark

You are correct, I needed the forum myself when building my machine.

[smeg up]

Great, thanks Eddy :)