[diarmaid]

No problem vukboban. All input is appreciated.

Bigz: I forgot to mention in the above post. Yes I will be covering all terminals with copious amounts of tape.

However I first have to build a control box to put it all on/in and hence will have to take it apart and put it all back together in this. I also have to re-wire my plug and transformer to include the earth connection. When its all in its permanent home and Im happy with the lengths and placements of the wires I'll put lots of tape on it.

Al:Im not sure of the current range on my 'multi-meter' but I'll try to find out. If it does I'll check using the placement you mention.

Thanks all.

[bigz1]

Just noticed you dont have the 4Amp or the 10Amp fuse in the wiring. If you short any connections(like I did) your gonna damage your driver board instead of blowing fuses.

May I also suggest replacing the wire with 14ga hook up wire(red/black) and use fastion connectors on the bridge rectifier or solder in place.

Regards

Liam

[diarmaid]

Which wire do you suggest replacing with the 14gauge hookup wire? And can I get this wire in my regular electrical supply store?

What are fastion connectors?

Thanks bigz.

[bigz1]

Meant Faston connectors(see attached). Wire is threaded through the plastic sleeve which is then crimped. Also available in piggyback type(Allows 2 wires on 1 terminal) and an eye type for threading a screw through as used on the capacitor. Avaiable in a variety of widths.

The wire and the connectors are common items.

[diarmaid]

Thats a good idea. I will look into them for the rectifier. If I could get the other type fo rthe capacitor it would really be great as the capacitor terminals are a right pain!

[bigz1]

Also get 2 GMA holders for the fuses. 1 x 4A SLO BLO GMA fuse. 1 X 10A GMA fuse and an A/C DPST(double pole single throw) switch.

[vukboban]

diarmaid,you don`t have to put two wires together onto the capacitor,
maybe it would be easier to do it on rectifier? so one pair of wires(red and black) should go from rectifier to cappacitor,and the other pair to the PCB

JUST AN IDEA

[diarmaid]

bigz: Thanks for the advice. I just googled GMA Holder! I will get them too. But one question, my output from the transformer is 23.6 Amps, so what size fuse should I get? Maybe 25amps instead of the 10?

Im also not sure where the two fuses get connected in the circuit and why I need the 4amp one?

vukboban:
Can you clarify what you mean?

Two wires from rectifier DC + and - to capacitor.
And two wires from rectifier DC + and - to the PCB.
And no wires from the capacitor to the PCB?

[vukboban]

yes

[Torchhead]

You have to test amps under load. No load = zero amps. This is like a bucket full of water, no current unitl you start to pour some out. To test current your ammeter needs to be connected in SERIES with the load (on one leg). Most meters will not read AC Current (although some will with a Clamp On type). If you don't have some pretty huge load resistors (several 100 W units) then you will have to wait until you can apply your motor loads. Don't be surprised if you don't hit anywhere near the combined plate current of the motors with all running under load.

Big transformers have a lot of thermal inertia. It takes full load over several minutes to move the temperature up and for it to migerate from the core of the windings out to the laminates and an equal amount of time to cool down. I wouldn't worry too much about load testing at this point. I suspect you will be fine unless you are running huge 36V servos.

[vukboban]

I like freehand tools

[vukboban]

and something about fuses,you should calculate max amp for all three steppers
(let`s say 3 x 3 A=9 A) and not max amp for the transformer (24 A),so 10 A fuse would be enough and reccomendable

[diarmaid]

Thanks for the advice Torchhead. I wont worry about the amp testing for the moment, It was just that I need to know it for setting my PCB for my steppers soon. But I can use the values from the calculations which should be near enough.

vukboban, if you think that'll work then I'll try it and see how it goes. It may have been what AlTheMan meant earlier. Thanks for the picture. Much appreciated. I will also calculate my amps that way.

bigz, I have asked in the HCNC forum about the resistors and the 2K 1W thingy. I guess they'll tell me for definate if I need them, but Im still not sure where I'd put them in. From the pictures on the HCNC site it looks like the 4Amp goes on the mains before the transformer. 4Amps seems like very little for a mains fuse?

[vukboban]

and don`t forget fuses for primary coil of transformer (500 VA/220 V ~2.3 A)

[diarmaid]

ehh....what? Where? How many?

Edit: No, seriously! What rating fuse, where to put it and how many of them?

[diarmaid]

HobbyCNC just told me that the fuses and the 2K 1W thingy were included in my package. They must be in the other bag that I haven't opened yet for the actual kit setup. I will check and get onto it tomorrow. I think if they were to be used at the driver board stage they should have been in the driver board kit, but Im sure there's a reason. Anyway, I'll try to identify them. For now, thanks, and goodnight.

[diarmaid]

Argg....double post....gremlins still in the software Paul!

[vukboban]

like this

[diarmaid]

GREAT! Many thanks for the picture, again.

But will a 4amp fuse be enough on my mains with my 13Amp wire?

And will 10amp fuse be enough on my transformer output which is rated at 24amps?

[vukboban]

never mind the wire or rated current of transformer;current (and max current)flowing through circuit is calculating by Ohm`s law ( P=U x I ),so primary current (from main supply to transformer) is 500 W (or VA) / 220 V=2.3 A,
closest rated fuse is 4 A. Maximum secundary current (from transformer to PCB) is all three steppers 3 x 3 A plus some current PCB is consuming about 0.2-0.3A,it wouldn`t hurt if U used bigger fuse,but it should break the circuit if for any reason current is much bigger than max current used by all three steppers,so it should be rated at 10 A