Amperage Draw

Can somebody inform me what the max amperage draw will be on the X Carve? I don’t need amps for the spindle, just the stock components and stock steppers

Not sure what prompted this question. It’s a little complicated, but if you want the absolute max, the 24 volt power supply that came with my kit is 300 watts. That would make it 300/24 = 12.5 amps the power supply can deliver.

Now, practically it won’t draw anywhere near that amount. If you had all stepper motors (NEMA 23s) with all phases on constantly it would be about 4 motors x 2 phases per motor x 2.8 amp per phase = 22.4 amps, but this condition will never happen because the stepper motor driver chips can’t handle that much current.

So, then it’s 3 driver chips with 2 phases per chip * 2.5 amps maximum current with appropriate cooling = 15 amps.

Since the stepper motors turn on and off rapidly they rarely draw full current for very long. Obviously, they don’t draw full current because the 300 watt power supply runs my X-carve well and it can only put out 12.5.amps.

Edit - Also the fan and blue LED on the gShield draw a little current, but it’s negligible when compared to the motors.

My concern is the 10 amp Emergency Stop switch. I am about to wire mine up. Many comments have been made about how to wire them in place. My actual concern comes into play when I read to hook the main power leg up to the NC side of the Estop.

An Emergenscy Stop switch should kill all power in my opinion. So I want to hook the wiring up so that it kills all incoming power to my unit. The problem is that I am running off of a 15 amp circuit. With the Estop switch only being rated for 10 amps, I can easily see exceeding this limit. With the Dwp611 pulling 7 amps by itself, then adding the extra draw of the XCarve core components, this should easily surpass the 10 amp threshold. Not to mention, some individuals are even adding a shop vac inline on the same circuit.

This all seems a little dangerous to me

I haven’t noticed any problems with it. You will likely have the 611 on the low end of the cutting range (unless you like replacing brushes often), so the power draw on that will be pretty minimal.

I looked at the E-Stop page and saw this question/answer. Maybe it’ll help you:


I have some concerns whether or not the E-stop can handle the new x-carve setup.

The E-stop is rated at 600V/10A while the new PSU is rated at 24V/16.7A.While the button explode, melt, electrocute or otherwise pose a danger to the safty of the users of the e-stop is placed between the outlet and the psu?

Also, the power entry model hase a fuse rated at 10A, guess that will blow as soon as the setup is turned on or have i missunderstod electronics?

      Asked by Oscar Sundström  on Mar 31, 2015

1 answer

Hi Oscar, thanks for your question.  After speaking with our product team, you would figure out the amps using the AC voltage.  The PSU rated at 24V/16.7A would produce 400W.  400W divided by 110V would equal less than 4A, so this e-stop should be more than capable.

I wired mine up so that it interrupts the feed from the power supply into the arduino box. Since the arduino can run with just the power from the USB cable, the arduino does actually stop running, but the g-shield and thus all the steppers stop dead in their tracks.

Yes, the DeWalt keeps spinning, and I could see where that could be a problem, but although I’ve used the e-stop several times, I’ve never been worried about stopping the spindle.

If you do want to stop the spindle, and assuming you’re using the 24v logic/on/off power feed to control a relay which controls the power to the DeWalt, the way I would do it is to hook up an NO relay between the power supply and the relay, and energize the relay from the out side of the e-stop.

That way, when the e-stop is not in “oh-crap mode”, the g-shield is in charge of the spindle power.

-Kelly

Ok, that’s a little different. On the A/C side 300 watt supply draws 300/120 = about 2.5 amps from your house outlet.

The emergency stop is primarily intended to shutdown the motors in a catastrophic event. Your shop vac can run all day without doing much damage, but a 30000rpm router moving around can cause a lot of damage.

So, if your E-stop is on the A/C side of the X-carve power supply and router then you’re probably ok if the E-stop is a quality unit. If you want to add the shop vac, then no.

Also, I have heard that many Chinese E-stops melt with as few as 5 amps even though they are rated at 10 amps.

Don’t scrimp on price for a safety device. Get a good quality E-stop or just have a clear path to your circuit breaker box.

Not quite. The Arduino and gShield logics get their power from the USB connector. The things powered by the 24 volt supply are: the fan, the blue LED on the gShield, the green LEDs on the gShield, and the motor voltage.

BTW, all of the processing goes on in the Arduino, the gShield is basically just three motor driver chips.

So let me see if I understand this correctly. when the Estop is placed between the power supply and the Gshield, the switch does not power everything down. The Arduino and Gshield logics still get power from the USB. The only things that fully stop are the fan, the LEDs on the Gshield, and the motor voltage.

How is this any different from killing all of the power at the source (instead of After the power supply unit)? Shouldn’t the Arduino and Gshield logics still be powered up by the USB.

If the dwp611 is hooked up to a relay being controlled by the Arduino, I am assuming that even when the power supply is interrupted, the Usb is still powering the Arduino allowing the spindle to stay on. So even when the Estop is engaged the spindle will stay on.

If I understand this properly, the proper wiring for the Estop will be between the PSU and the Gshield on the NC side of a switch. The Spindle control wire from the Spindle Enable pin on the Arduino also needs to be connected to a NC switch. With this set up, the power will be cut to the Gshield motor stopping the motors and also turn off the relay controlling the spindle.

Most of these switches have both a NC and a NO circuit , but if you have two switches, then you can swap out the circuits to have a switch with 2-NC circuits and a switch with 2-NO circuits. So the above example is a possibility.

The problem that I see with this is that the Arduino is still receiving power, so is it still sending the Gshield the information, just the Gshield is not responding bc there is no motor voltage. I assume that if the Estop is pressed, then later I can go back to the UGS and restart from a line prior to having to engage the Estop. Am I correct on this?

Aren’t all of these things made in China anymore???

Safety is my concern that is why I am bringing up this question. If I have a 15 amp breaker and the Estop switch dies or melts then the 15 amp breaker should still pop, correct?

Thank you to everyone for their input.

Yes.

Yes.

Yes.

Yes. This would be a DPDT switch.

Yes.

Yes and no.

Just like everything else, you can get good quality and bad quality from any country. It’s just a little more difficult to separate the good from the bad with Chinese manufacturing.

Yes, If the circuit draws more than 15 amps.

Larry, your knowledge is much appreciated, Thank You.

So I think I am going to wire up the EStop as a DPDT switch. So that the power is cut between the Arduino and PSU by the switch and also at the same time breaks the signal from the Spindle enable to the relay. This will keep the Estop switch from having to possibly carry more than 10amps.

At this point the vac shouldn’t be a concern on the other relay.

I think I might run a paddle switch in-line on the Power Line. This will be another Kill Switch.

I can power the computer on the same paddle switch that kills the power to the main line in. This will also cut the power to the USB powering the Arduino, as long as there is no battery back up or lap top battery after the switch. This will kill all power.

With a paddle switch I won’t have to worry about the 10 amp limit like on the Estop.

Again, thank you for your assistance. My wiring schematics have just been altered because of this conversation

If it helps, I ran 2 circuits to my CNC cart (by extension cord). Circuit #1 powers the X-Carve power supply and 611, and has the E-Stop wired so that the circuit it is completely dead when pressed in. Circuit #2 powers the auxiliary outlets (for laptop) and the shopvac.

Thank you Robert.

My system will actually be running 220v power in that splits into two 110v legs. This is what everything will be powered by on my set up. Basically the same as yours but I am wiring directly to the breaker box. This way I don’t have to worry about which circuit I am on or what else is running on that breaker. I have all of my large tools in my shop wired this way.

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What is a good quality e-stop. 10A and higher on 220V?
Put out some links/urls please.

I noticed my e-stop only did 1.5A on 220V, so I ordered the one from Inventables in stead. But, is that also a cheap crappy one?
5$ e-stop doesn’t sound like high quality.

Unfortunately, this is not something that I use so I don’t have a good source for you.

I use the one from Inventables, and it seems good to me.

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This is what I already have on hand. There are others similar to it on Grizzly.

http://grizzly.com/products/220V-Paddle-On-Off-Switch/H8242

It is not necessarily an estop but will work all the same for 220v power.

I am also considering using this.

The only reason that I am considering the LR2244 is bc I have it laying on a shelf in he back room. It was a leftover from my previous DC system. I think that it is nice to have the remote to use as a kill switch from another room or from a camera system. It is a hefty investment but it is also a true Kill Switch.

Some might be concerned about accidental trips. All I can say is my DC never kicked on/off unless the button was “Pushed”. Wether it was purposely or accidentally pushed is another story. This is why I would not recommend carrying it around on you or in your pocket. Rather than on your person have it sitting or mounted within arms length but where the off button can not be accidently pushed.

Options… They are endless. Lol.

While I like the Inventables E-stop, I’d say go with what you have. That looks like a nice unit, I wish I had one for my DC.

It is a very nice unit, that is just collecting dust in my shop. And not in a good way. Lol

With this wired in-line, I can still add the DPDT Estop to control the power of the PSU and to kill the spindle.

Kinda best of both worlds.
Gives me a working Estop
Gives me a working estop that kills all power to everything
AND it adds a remote that I can gives me an Estop from anywhere in my house or shop.

Can’t beat that in my book. (Well, someone probably can. This forum is the INVENTABLES forum after all). Lol

Wow, that must be the boss kill switch :smile:

About the Arduino. If you have an e-stop with both NO and NC you can connect it directly to a pin on the Arduino and have a small program to put the board to sleep when it detects a signal on that pin.
But, I’m not sure if the X-carve Arduino can take custom code or if it’s preloaded with some code for the g-shield?

Edit:
Some hints here maybe:
https://blog.adafruit.com/2012/03/27/ask-an-educator-is-there-a-way-for-an-arduino-to-turn-itself-off/

You would have to over-write grbl to run a small program, so this wouldn’t work.

There is a provision in grbl to pause a job if you need manual intervention during your carve. Keep in mind that this thread is about E-stop - something really bad happened so you want to crash the machine before more damage can occur. During normal operations there is a better way to stop things.