Router overheating

[alarants]

Hi,

I am trying 3D engraving and that means of working 1-2 hours without any stops. Sometimes my router motor overheats and turns itself off. At the same time axis motors continue to work. Bad situation. Does anybody have an experience about how to get signal from router when it turns off to turn off axis motors as well.

Regards

[Nightz]

Try a current probe around the router power cable (one wire). Have this tied to a circuit that shuts off motors (like your e-stop input) when current stops flowing. Will need to find an AC current probe.

This of course is a generic fix, I'm sure a few other details will have to be considered to elimiate false positives and such but, it's a start.

-Rocko

[dighsx]

What about blowing air on the router to keep it cool. Check out this post for an example: http://www.cnczone.com/forums/showthread.php?t=13815

[JavaDog]

Originally Posted by Nightz Try a current probe around the router power cable (one wire). Have this tied to a circuit that shuts off motors (like your e-stop input) when current stops flowing. Will need to find an AC current probe. This of course is a generic fix, I'm sure a few other details will have to be considered to elimiate false positives and such but, it's a start. -Rocko

That's a pretty nifty idea, actually!

[alarants]

The idea is good. So I bought 3 meters of wire and wraped it around the power cable. I got a coil 11 cm long. Classic transformator. The result was 0.0000001A. It is not enough to do anything with it.

[HuFlungDung]

Can you make use of the break in the circuit in the router itself when it trips out? Assuming this is 110v, have your main motor power supplied through a magnetic contactor. The holding coil latch circuit for the contactor will also be fed 110v from the return side of the contactor. Now if you can determine which lead to your motor is the hot wire, feed one end of the latch circuit with the return wire from the motor(the one that goes dead when the router trips out). So, when the router trips out, the contactor opens, and using a set of auxiliary contacts on the side of the contactor to close the Estop circuit, said circuit will now be broken and Estop your controller.

Some electrical genius can probably design this circuit much more succinctly than I have described it.

[Nightz]

Originally Posted by alarants The idea is good. So I bought 3 meters of wire and wraped it around the power cable. I got a coil 11 cm long. Classic transformator. The result was 0.0000001A. It is not enough to do anything with it.

Your missing "the circuit" that I mentioned in my short description. You need an amplifier to make your current readable by a switch. I would see if I could find an AC Current Transducer. The transducer will require some sort of power supply and will output an amplified voltage proportional to the current flow. The transducer will probably have a small POT on the side to adjust sensitivity. You still need to have a circuit or switch that trips when the transducer voltage drops outs (router shuts off).

I could be wrong, but it looks like you have your coil around the whole AC power cable for the router. You want your coil around ONE of the wires in the cable. Otherwise your current in one direction will cancel the current in the other. Maybe thats why your output is low.

A whole new option would be to stick a thermal couple in your router. Figure out the temperature when your router shuts off. Again some sort of analog to digital circuit will be required to shut your motors off or at least warn you when your reaching your critical temp.

Feel free to ask if you have questions.....
-Rocko

[Parameter]

How about using a dollar store AC probe stuck to the motor and replace the indicator bulb by a switching transistor connected to the e-stop pin using a resistor and 5v? That could do it under 5$!

well, the idea could be developped but here is how I would do it.

-get a cheap power probe at the dolar store
-replace the bulb by long wires (braided or twisted = better)
-make a quick circuit that takes the current and switch a transistor ON when probe power if OFF
-then feed 5v for the e-stop thru the transistor switch just like a limit switch is wired.

You would need a bypass switch to get the machine in place first, then, flip over the switch and go to bed... I tought about that one quite a bit since I just got my copy of BobArt and sure know it can be long at 10IPM... hehe

Para

[ger21]

Imo, the best thing to do would be to get a better router, or provide more cooling to it. If it's getting hot enough to turn itself off, it can't be good for the router.

[2muchstuff]

alarants,
It looks like you wound your coil around the entire power cable, all 3 wires. Try this, wrap your coil around just the hot wire. You should get more current. I did some work for a guy years back at his house who was an inventor. He had a panel at his back door full of L.E.D.'s labeled coffee pot, stereo, hall light........ and so on. We got to talking about it and in a nut shell here's what he had. A torroid/ferrite coil with a 1/2" inside diameter wrapped with many turns of wire, the two wires from the coil were ran back to the panel driving an L.E.D. If the item didn't draw enough to light the L.E.D., he would loop the hot wire thru the coil a few more times till it lit. This way he could tell if he had left something on when he left for the day. Neat idea eh. The coil drove the L.E.D. directly. He also had shown me some that had the L.E.D. molded into the plastic cover. I think I saw some later on that were sold to indicate the power status of 3 phase lines. They just slipped over the wire. Hope this helps you out.

[unterhaus]

Small current transformers are available on the surplus market. Or you can take apart a pc power supply and get a small toroid and wind your own.

This isn't going to work if the hot and neutral wires go through the transformer, the currents cancel each other out.

[2muchstuff]

Unterhaus,
" the currents will cancel themselves out"
Thats what I was trying to say. I also forgot to mention that a converted voltage probe idea will not work because if the router overheats and stops, there is still voltage on the line and the status of the probe will not change. On the other hand if you are sensing current flow and the router stops, then the status will change on the L.E.D.