<html><head></head><body><div style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div></div><div id="ydpcc157a41yahoo_quoted_7288058774" class="ydpcc157a41yahoo_quoted"><div style="font-family:'Helvetica Neue', Helvetica, Arial, sans-serif;font-size:13px;color:#26282a;">I think we have a winner!<div><div style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div><br></div><div>Found a 5V supply that says it has 3.0A. Now the larger stepper does its rotations.</div><div><br></div><div>The wiring is:</div><div>Black A+</div><div>Green A -</div><div>Red B+</div><div>Blue B -<br></div>
<div><br></div><div>Replaced my adifruit stepper, now the rope is pushed with authority.</div><div><br></div><div>Next: find out why arduino code has bugs. Simple program uses Stepper.h and tells the stepper to move one revolution, pause 2 secs, continue in same direction. Sometimes the motor goes backwards though. What fun.<br></div><div><br></div><div>Thanks</div><div><br></div><div>Craig<br></div><div><br></div>
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On Monday, January 22, 2018, 11:13:07 PM EST, <jonjwolfe@anibit.com> wrote:
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<div><div dir="ltr"><br clear="none">As soon as I sent that last mail, I thought maybe the supply isn't <br clear="none">crapped out at all, you're probably just supplying too much voltage to <br clear="none">the motor, and a PTC fuse in the wall wart is tripping, causing the low <br clear="none">current reading you are seeing (sometimes they hum or squeal when this <br clear="none">happens). That PTC might actually be saving you from burning out the <br clear="none">motor(though PTCs will burn out eventually too if abused, which will <br clear="none">ruin the power supply).<br clear="none"><br clear="none">I would recommend you DO NOT try a different power supply, but first <br clear="none">make sure you're current limiting to 2 Amps to the motor. The motor when <br clear="none">it sees 12V is going to try to draw 10.9 amps! That will surely make the <br clear="none">wall wart freak out, which is probably why the current reading goes so <br clear="none">low. If you did find a supply that could give you that many amps, then <br clear="none">your motor would quickly self-destruct.<br clear="none"><br clear="none"><br clear="none"><br clear="none"><br clear="none"><div class="ydp5377afabyqt1031399263" id="ydp5377afabyqtfd18965"><br clear="none">On 2018-01-22 21:00, <a shape="rect" href="mailto:jonjwolfe@anibit.com" rel="nofollow" target="_blank">jonjwolfe@anibit.com</a> wrote:<br clear="none">> My first suspect would be that your recycled power supply is crapping<br clear="none">> out. Can you test it with a different supply? Those are the same<br clear="none">> motors used on a lot of 3D printers, so they should have a decent<br clear="none">> amount of torque. Is your "capstan" wheel large? If you're shopping<br clear="none">> for steppers, look at the holding torque values when comparing them.<br clear="none">> <br clear="none">> There is also the possibility that you burned the motor out (though in<br clear="none">> my experience they seem to be able to withstand a fair amount of<br clear="none">> abuse). The current rating is what is important for steppers, so at 2A<br clear="none">> and 1.1 Ohms, the max voltage at hold should be 2.2 Volts. That's<br clear="none">> quite lower than what you're giving it. I would measure the resistance<br clear="none">> across the appropriate leads to make sure you're getting around 1.1<br clear="none">> Ohms. If not, the motor might be fried.<br clear="none">> <br clear="none">> <br clear="none">> Also, steppers loose torque dramatically as they speed up, so the<br clear="none">> drivers like the Pololu a4988 and its kin can help by letting you<br clear="none">> safely "overdrive" the stepper by limiting the current, but supplying<br clear="none">> a higher voltage than what the motor is listed for. They will let you<br clear="none">> supply 12V and, at hold, will drop the voltage down to 2.2V. Once the<br clear="none">> motor is moving and providing back emf (or whatever it is called for<br clear="none">> steppers, same principle), the Pololu drivers will allow higher<br clear="none">> voltages to pass through it to keep the current at 2Amps as much as it<br clear="none">> can. You'll have to browse Pololu's stepper driver offerings to find<br clear="none">> one that can do 2A.<br clear="none">> <br clear="none">> I'm pretty sure the L298-based drivers are nowhere near that<br clear="none">> sophisticated, but tend to have a better current/price ratio, so if<br clear="none">> they work for your application, they make sense.<br clear="none">> <br clear="none">> Also, the Pololu drivers do microstepping, which can lower the<br clear="none">> instantaneous torque applied and possibly help you avoid stalling, if<br clear="none">> you "accelerate" the step speed. I know first hand in CNC applications<br clear="none">> steppers can be very sensitive to the acceleration rate.<br clear="none">> <br clear="none">> <br clear="none">> <br clear="none">> On 2018-01-22 19:52, Craig Cook via TriEmbed wrote:<br clear="none">>> I have a project where I need to move a stepper motor, it needs to<br clear="none">>> push a 1/4 inch rope through a roller.<br clear="none">>> <br clear="none">>> I have one of these working: <a shape="rect" href="https://www.adafruit.com/product/324 " rel="nofollow" target="_blank">https://www.adafruit.com/product/324 </a>but<br clear="none">>> it seems to lack pushing power. If I help pull the the rope it works<br clear="none">>> well. I think I need a more powerful stepper.<br clear="none">>> <br clear="none">>> I also have one of these:<br clear="none">>> <a shape="rect" href="https://smile.amazon.com/gp/product/B00PNEQI7W/ref=oh_aui_search_detailpage?ie=UTF8&psc=1" rel="nofollow" target="_blank">https://smile.amazon.com/gp/product/B00PNEQI7W/ref=oh_aui_search_detailpage?ie=UTF8&psc=1</a><br clear="none">>> (17HS16-2004S1)<br clear="none">>> <br clear="none">>> I am using this to drive them:<br clear="none">>> <a shape="rect" href="https://smile.amazon.com/gp/product/B014KMHSW6/ref=ask_ql_qh_dp_hza" rel="nofollow" target="_blank">https://smile.amazon.com/gp/product/B014KMHSW6/ref=ask_ql_qh_dp_hza</a><br clear="none">>> <br clear="none">>> I think it should work. My power supply says it is DC output 12 V,<br clear="none">>> 3.33A Max. (I think it came from an old laptop or printer)<br clear="none">>> <br clear="none">>> With no pressure on the Adifruit stepper it seems to work. When I try<br clear="none">>> the other stepper, it gets lots of pauses, the power light on the<br clear="none">>> L298N flashes on sometimes and the stepper hums like it is trying to<br clear="none">>> move.<br clear="none">>> <br clear="none">>> I'm using an Arduino Uno to control everything.<br clear="none">>> <br clear="none">>> When the larger stepper is trying to run I measure around 3 V at the<br clear="none">>> power terminals on the L298N, around 0.01 mA (using breadboard jumper<br clear="none">>> wires to connect power supply to controller).<br clear="none">>> <br clear="none">>> Do I need a different motor controller? Should I find a different<br clear="none">>> stepper? Should I buy a bench power supply?<br clear="none">>> <br clear="none">>> Thanks<br clear="none">>> <br clear="none">>> Craig<br clear="none">>> _______________________________________________<br clear="none">>> Triangle, NC Embedded Computing mailing list<br clear="none">>> <a shape="rect" href="mailto:TriEmbed@triembed.org" rel="nofollow" target="_blank">TriEmbed@triembed.org</a><br clear="none">>> <a shape="rect" href="http://mail.triembed.org/mailman/listinfo/triembed_triembed.org" rel="nofollow" target="_blank">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org</a><br clear="none">>> TriEmbed web site: <a shape="rect" href="http://TriEmbed.org" rel="nofollow" target="_blank">http://TriEmbed.org</a><br clear="none">>> To unsubscribe send admin mail:<br clear="none">>> mailto:<a shape="rect" href="mailto:unsubscribe@triembed.org" rel="nofollow" target="_blank">unsubscribe@triembed.org</a>?subject=UNSUBSCRIBE ME<br clear="none"></div></div></div>
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