About JRK

Hi. i'm looking at pololu motor drivers.

http://www.pololu.com/product/1381/specs#note3

Thats able to power 18 volts and 25 amps constant. is it able to handle at 12 volts 37.5 amps constant?

Which is the best to control a 12v 23A nominal power motor? ZYT-90

Thanks

Its a motor controller that requires an control board like an arduino to run it. This is not a JRK. However it looks like it has enough power to run a zyt motor.
I run the 12v12 JRK on my zyt-90 style motors with no problem.

Thanks for the acalaration i have no idea of programming. Whats the difference between a JRK, motomonster, motorshield,pololu, kangaroo, etc, etc? for me they are almost the same thing but different amperage and its obvious than not.

Yep i already have an arduino uno

12v12A, isn it a risk of burning it?

http://www.motioncontrolproducts.com/pdfs/pmdc_2.pdf

ZYT-90 is rated at 23 A nominal power. I'm a bit confused.

Is an ard+pololu enough to power it? plus a decent PSU.

the board looks powerful enough, but as I am not familiar with it, I cannot answer.
The 12v12 JRK we can spike at 45 amps and run at 35 amps continuous all day with heatsink and cooling.

I believe you believe it will do 35 amps continuous @bsft. But I am skeptical since it’s only rated at 12 amps. Can you provide proof from your tests for those of us who find that a little hard to believe? Since motion simulators don’t do a continuous draw of current at a particular amperage how did you determine it would do 35 amps continuously all day?

@BlazinH , sorry, i dont have documented proof.
yes it doesnt run that hard all day, but with a rough profile and the road vibration and other settings on brutal, it runs pretty damn close, judging by how warm the motors and heat sinks get.
My original motor supplier , when I bought the 200 watt motors, when i told him what I was going to do, he immediately voided warranty. I then reported back to him over the next 12 months of thrashing the hell out of the motors. I calculated that a 200 watt motor was being overdriven to over 500 watts. He even corrected his specs on the website , stating they could be over driven, but not recommended. those original motors are still going strong 3 years later.
But the JRK does have a max current limiting feature and I have tested my motors with various profiles at 38 amps set max current until it tripped out. I then moved max current up to 40 and waited it to trip out again.
I fiddled with profiles so i got decent motion so it didnt go over the 38 amps mark. But she got mighty close.
It had no effect on the JRK as long as it had heatsink on big chip and cooling with a fan. I havent had the JRK thermal trip out surprisingly
I recall this was running at 38 amps set max current

and that was with cheap pots, badly placed motors, bad PID, etc.
These days I just run 0 (unlimited), to stop it tripping out, and run profiles at "medium" settings for me, so they are a good feel and after an hour on the sim, I have to get off and stretch. So its probably not running that hard, but if I do wind him up, its not a problem.
I can set the profile to vicious and I feel real strain after 15-20 mins.
I recall @eaorobbie runs his motors at teeth shattering profiles,and from what I hear over mumble chat with him in game, his voice is "blurred" by motion.
I should really run a shunt on the motor draw line to get an idea what it sucks in power at least.
Hope that helps a bit.
Pololu recommend certain limits, and were stumped on how hard we push them. They are reluctant to give us warranty (dunno why) , but do offer good replacement service at considerably reduced costs.
Cheers, Dave.

Of course my numbers are without a heatsink and cooling, i do know a heatsink improves that but didnt know it could TRIPLE specs on sheet. i'm so glad to hear that.

I think a proper CPU would cover the chip, but how do you fix it to the board? or what kind of coolers are u using? Computer fans draw low amps at 12v

yes i've read you can set a max amp draw on the pololu settings easy

Thanks guys!!!

Hi, look what i have just found

http://www.electan.com/pololu-jrk-12v12-usb-motor-controller-with-feedback-p-5218.html

Pololu 12v12 unassembled 119 euros ¿?¿?

Is this so expensive? This is JRK.

As i already have an ard, is this suitable?

http://www.electan.com/pololu-simple-highpower-motor-controller-24v12-fully-assembled-p-5211.html

I need to run 12v 25A constant, is it possible to set it to 12v, add a heatsink and handle 25A??
In the second case i think the feedback goes to the ard, on the analog port, isnt it?

I am not sure about the ard and motor drives, sorry.
yes the JRK is expensive, but its a great little board.
To put any heatsink of the big chip, you can use a heatsink with a stick on thermal pad or just use thermal paste and hot glue the edges of the heatsink to the blue terminals, taking care not to let the heatsink touch the capacitors.
I will take a pic tomorrow and show you.
its late here, 11pm.

This could be run with the Ard codes we have available at present but may need a little code change as it uses a pwm pin for speed and drives a pin low/high for direction will only produce 12amp continuous and expect 20-24amp peaks, a good heat sink and fan.

This might be a better choice.
http://www.pololu.com/product/2507

Nice assertion @bsft (aka Mr. Lane)! Now I think I’m getting your meaning. I have noticed that mosfets can usually handle double their stated continuous amperage output for very short periods (peak current). Also, it appears that the main “killer” of mosfets is heat, not amperage. Since the Jrk doesn’t come with a heat sink on it, there is no doubt that with proper cooling, you can get more than 12 amps continuous. If you can add 6 or 7 more amps to the continuous output, then, in theory, you should be able to run 36-38 amp peaks. Exactly how high and long will depend on the efficiency of the heat sink(s) you are using. But as long as you can keep the heat low enough in your mosfets to keep them from burning out internal circuitry they should remain functional. However, I have noticed on a sabertooth controller that I used very hard that the mosfets power output curve can diminish when the mosfets are overstressed for extended periods.
One more observation is that your rig in the posted video says its running the other software. Simtools is definitely faster and will result in higher peak currents!

Ps. The diminished power output curve of my overstressed sabertooth could be due to a diminished capacitor vs the mosfets.

Thanks robbie, i didnt read that dual motor are able to run 1 motor at double amp. i plan to use a CPU cooler, some of them are rated at 200W heat disipation, for 20 euros, so it'll be ok. You know what i am building and that are great news for me. I guess the ard catches the pot signal, and it sends the proper data to the pololu, right?with positive or negative direction.


I also have to weld that so thats a thing i dont want to do i'll order that anyway.

What temperatures are right for the pololu chip? I have the idea of installing simple temp readers and show it in a small number screen outside the actuator, would be cool

@BlazinH , yes I forgot that sim used to run the "other" software. Simtools probably does produce more motion increasing current, havent really paid attention. However after beta testing both, Simtools is more refined, so , for me, I can set the motion less harsh to achieve the same result.

I use a simple little heatsink from jaycar about 12x12x5mm actually quiet small in size, with a single 120mm fan on top and a decent space under the card, as the pololu boards are designed to dissipate heat from their underside as well, they keep that cool you can touch them without being burnt, no fan and heatsink they will burn your finger on touch. So it only takes a little one and a fan to keep them cool. But bigger is always better in this case.

Yes the Ard will handle the closed loop for position control, ie it does all the thinking, and needs the pots to be connected to it, to feedback the position the lever is in. And then decides which direction and what speed is needed in order to reach the target before it gets a new command to move again.

The temps are on the pololu data sheet, would recommend a separate ard to control the temp dials and could even have a pot to set when the fan kicks into cool off the drivers, my preferred method is , drivers on then fans are on, but I do push the little buggers as hard as I can , all the time. lol.

Hi, ordered a Pololu dual VHN5019 motor driver shield for arduino, plus another arduino UNO. 2-3 weeks to have it at home.

I am also ordering these, didnt do it yet.

http://www.ebay.es/itm/Disipadores-..._DefaultDomain_186&hash=item19f303ef7c&_uhb=1

4x heatsinks 15x15mm 8mm tall. are them ok?, 3,20 euros at home plus a 120mm fan which i was already planning to buy.

Thanks!!