MK1 Steel router build log 1500x800x200

[Davek0974]

Decided and ordered.

Its gonna be 4 steppers

4x 4amp 4Nm nema23 All round : cnc4you

Does anybody have a realistic number on power needed for those?

I would like to do a dual diy toroidal transformer setup.

So 2 dual 24v transformers , dual rectifier.
dual 68volt circuit.

1 for dual x motors and
1 for the y and z motor.

Is it as simple as 2x4 Amp stepper, so 8 to 10 Amp 400 to 500VA per transformer?

Or will less power be sufficient?

1 kW sounds like a lot and ott.

I gues not many times all 4 steppers are running full throttle all the time...


Anyone?


Grtz Bert.

Also ... is there such a thing as minimum belt length?




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I would go with a 600W psu for 4 x 4Nm motors

[driftspin]

I would go with a 600W psu for 4 x 4Nm motors

Oh ok, that is a lot less then i expected..

Thanx for that.

Grtz. Bert.






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[Neale]

Yes, you don't have to add together the peak demand to give a rating if you are using a linear PSU. For one thing, as you say, the chance that all four motors will be running at full power at the same time is tiny. The second is that the load via the drivers is more like a series of short pulses than a continuous current and the smoothing capacitors can provide this pulse load very easily, and the rest of the PSU components just see the average load. In practice, a rough rule of thumb is to calculate maximum load, and use a PSU rated at about 30% less. The final point is that because of the way the drivers work, you do not actually need a very smooth well-regulated power supply (within reason). My 68V PSU has a measured 10V or so ripple under load. This does not cause any problems at all.

These points are also why a cheap switch-mode PSU is less suitable. It does not cope with peak loads very well, so it has to be over-specified to cope with the maximum peak load, not an average load.

I use a 650 VA toroidal which replaced a 500VA transformer which failed. The bigger transformer was only a couple of pounds more, as I remember, but measuring the average power consumption of the machine, I could probably have used something smaller. That's driving 4x3Nm Nema 23 steppers, max current probably about 4A per motor.

[JAZZCNC]

Why dual transformers.? Don't see the point just adding expense for no gain. I've built many many PSU's and never had one faulty yet and that's running upto 5 motors.

I'd also just buy regulated linear 24Vdc supply it's cheaper. Doesn't make any difference just for powering switches or Boards etc and actually better for electronics because don't like flutating power.

You'd get away with 500Va but 625Va will give little spare current but you might get fuse tripping with inrush in which case just use D rated MCB.
Voltage then I'd aim to run steppers around 65-70Vdc. So you'll need to check your mains input but roughly 2 x 24Vac for series wired or 2 x 48 for parallel wired.

[driftspin]

Thanks JAZZCNC,


So a lot is on track..

Can make my bomlist for farnell final than.


Is there an eu reseller for ub 1?

Vat/import tax is adding up...

Grtz Bert


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[Clive S]

Bert Did you check out the rapidonline list I sent you for the power supply. post #95

[driftspin]

Bert Did you check out the rapidonline list I sent you for the power supply. post #95

Hi Clive S,
Uh farnell vs Rapid online.... that was a quick 50% price drop...
Thanks, you just earned some beers :-)


Just checked the mains voltage
Now it is not ~225volts


It is 235.4 volts on fluke 87 V.
Oopsie +10 volts, so 24 or 25 volt secondary still?



Theory : uh was it like ....
(25+25)*sqrt 2 / 230v*235v?? = 72,2 volts
(24+24)*sqrt 2 / 230v*235v?? = 69.4 volts
Goal : 68volts DC

Well, rectifier steals maybe 1 volt (Vf =1.1 volt) ?

Can you please confirm? 24+24 is harder to find.



Post #95 The links are shorted and messed up somehow,
hard to handle on smart phone icw google, so on a pc now:

I had google find me the bom list you suggest.

-DC Components KBPC5006 Bridge Rectifier 50A 600V.

OK 50Amps@600volts :-) Nice

1*
-Vigortronix VTX-146-500-225 500VA Toroidal Transformer 2x115V Primary 2 x 25V
OK, uh dual primairy? 2 series 115volts=230 volts?

Do i want single 230v or dual 115v primairy, and why is that?

3*
- LCR EP0882-P 35mm Nylon Capacitor Mounting Clamp
OK


3*
- Jianghai ECS2ABZ472MT6P23550 4700uF 100V Snap-in Alum. Elect. Cap. 85° 4khrs
OK




Thanks again for this Clive S.


Grtz Bert.

[Clive S]

Theory : uh was it like ....
(25+25)*sqrt 2 / 230v*235v?? = 72,2 volts
(24+24)*sqrt 2 / 230v*235v?? = 69.4 volts
Goal : 68volts DC

Well, rectifier steals maybe 1 volt (Vf =1.1 volt) ?

Can you please confirm? 24+24 is harder to find.

Ok I am not a math person but I think you might be doing this the wrong way.

25-25 = 50 x 1.414 = 70.07 - rectifier 2 x 1.1 v = 68.5v

Single or double primary no difference, dual primary are easier to find. You won't have any trouble with 25-25 or 24-24 v sec.

Don't forget you are measuring V without load. You also said you have a 25Mtr run

Sorry about the links the forum shortened them.

[driftspin]

Ok I am not a math person but I think you might be doing this the wrong way.

25-25 = 50 x 1.414 = 70.07 - rectifier 2 x 1.1 v = 68.5v

Single or double primary no difference, dual primary are easier to find. You won't have any trouble with 25-25 or 24-24 v sec.

Don't forget you are measuring V without load. You also said you have a 25Mtr run

Sorry about the links the forum shortened them.

Hi Clive S ...

I was just compensating for the raised mains voltage 235 vs 230...

So what about the drives.
I understand leadshine does not manufacture am882 no more ? Where do those am882's come from then?
Good / bad clones?
Any reputable place to buy them ?

So... can one use the uc300 eth with gcode to control spindle speed over 0-10v from the ub1 ?

Is uc software licence bound to the motioncontroller or to the pc hardware?


Grtz Bert.



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[Nr1madman]

Hello again!

Doesnt matter if you have dual 115 primaries or a single 230v. You can connect 2x115 in series to get 1x230 :)

Same with the secondaries.. you can look for 2x24v or 1x48 or 2x48v .. same thing for your application!

You might have an easier time finding the right stuff from rs online, just a tip

For example : https://uk.rs-online.com/mobile/p/to...rmers/1176071/

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