Hot motors

I just got done with my test cube, yaay! I'm looking forward to printing more parts but my motors were scorching hot . I have the potentiometers set all the way back except the extruder motor which is .42V. Any suggestions? Thanks.

Motors should be barely warm. What is their spec?
Set all the other motors to 0.4v
Make sure the axes' are not binding.

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_______________________________________
Waitaki 3D Printer

I'm not sure what problem I may be having with the axes, but they slide freely all day long until I start testing in pronterface, they will me well the first couple of times then get extremely hard to move, even with the hands. I have no idea what is causing that to happen. I will set them all to .4V

I should have mentioned, it is a Makerfarm Prusa i3

Once you have moved an axis with the contoller, the controller will forcefully hold that axis still when its not moving it. There are exceptions to that rule especially for t z axix.

When the printer is powered down all axises should move freely by hand with only slight resistance from the detent torque of the motors.

If your axises move freely by hand, your motors are the correct size, and your v-ref is set to .4VDC then your motors shouldn't get hot. If all of that is good, I would check the voltage of your power supply while the printer is running. If its more than 12VDC this could be causing excess current. Amps = Volts / Ohms.

Great. I will check the PSU voltage. I have them all set to .4v and they still are getting quite hot. thanks for the help.

nibake Wrote:
-------------------------------------------------------
> Great. I will check the PSU voltage. I have them
> all set to .4v and they still are getting quite
> hot. thanks for the help.


Hello,

I have asked Colin from makerfarm this aswell,
He told me its normal and that his printers with over 10 000 hours o printing has the same thing, that you can't touch em due they are to hot,
I didnt mess with my voltage due if you do them to low it will miss steps and i just dont wanna mess with all those things when it should be ok.

Best regards,
Luigi

redo

Edited 1 time(s). Last edit at 08/25/2013 01:23AM by appdev007.

I'm a bit surprised to hear this out of maker farm. If this is the case, I'm guessing they are rated to a lower current. I'm seeing posts that says the are .5 amp motors instead of 1 amp motors. I'm betting they weren't meant to be used at 12v. nibake, where did you get your motors? What numbers do they have printed on them?

luigi Wrote:
-------------------------------------------------------
> nibake Wrote:
> --------------------------------------------------
> -----
> > Great. I will check the PSU voltage. I have
> them
> > all set to .4v and they still are getting quite
> > hot. thanks for the help.
>
>
> Hello,
>
> I have asked Colin from makerfarm this aswell,
> He told me its normal and that his printers with
> over 10 000 hours o printing has the same thing,
> that you can't touch em due they are to hot,
> I didnt mess with my voltage due if you do them to
> low it will miss steps and i just dont wanna mess
> with all those things when it should be ok.
>
> Best regards,
> Luigi

Quote: can't touch em due they are to hot,

Jeez!

---

_______________________________________
Waitaki 3D Printer

I also got the makerfarm prusa i3 kit a couple weeks ago.

they are: 42BHH48-050-24A

appdev007 Wrote:
-------------------------------------------------------
> I'm a bit surprised to hear this out of maker
> farm. If this is the case, I'm guessing they are
> rated to a lower current. I'm seeing posts that
> says the are .5 amp motors instead of 1 amp
> motors. I'm betting they weren't meant to be used
> at 12v. nibake, where did you get your motors?
> What numbers do they have printed on them?
>
> luigi Wrote:
> --------------------------------------------------
> -----
> > nibake Wrote:
> >
> --------------------------------------------------
>
> > -----
> > > Great. I will check the PSU voltage. I have
> > them
> > > all set to .4v and they still are getting
> quite
> > > hot. thanks for the help.
> >
> >
> > Hello,
> >
> > I have asked Colin from makerfarm this aswell,
> > He told me its normal and that his printers
> with
> > over 10 000 hours o printing has the same
> thing,
> > that you can't touch em due they are to hot,
> > I didnt mess with my voltage due if you do them
> to
> > low it will miss steps and i just dont wanna
> mess
> > with all those things when it should be ok.
> >
> > Best regards,
> > Luigi

Edited 1 time(s). Last edit at 08/25/2013 08:47AM by luigi.

Well, I searched for that part number, but didn't get conclusive results. I emailed them asking for a data sheet. We will see what I get.

I have read that they are .5amp motors. I think part of the problem is my power supply. I was supposed to buy a power suppy that could put out at least 16 amps, 11A in the left + - connectors and 5A on the right, according to Colin. I bought a power supply that outputs 20A at 12V and all outputs are the same, so I essentially have 20A going into each of the two connections? Or 10A, idk, I'm no electrician. At any rate, I'm afraid to do more than 1 short print a night cause I don't want to fry my motors, they're probably not cheap. If I got resistors to bring my power to 11A on the one side and 5A on the right, then set my pots to .4V would that work??? Thanks so much for your help.

Edited 1 time(s). Last edit at 08/25/2013 10:10AM by nibake.

Well your PSU wouldnt be the problem since the ramps would normaly get those amps down when it reaches your stepper motor.

Also there arent realy expensive, about 15 dollars a motor i think.

nibake Wrote:
-------------------------------------------------------
> I have read that they are .5amp motors. I think
> part of the problem is my power supply. I was
> supposed to buy a power suppy that could put out
> at least 16 amps, 11A in the left + - connectors
> and 5A on the right, according to Colin. I bought
> a power supply that outputs 20A at 12V and all
> outputs are the same, so I essentially have 20A
> going into each of the two connections? Or 10A,
> idk, I'm no electrician. At any rate, I'm afraid
> to do more than 1 short print a night cause I
> don't want to fry my motors, they're probably not
> cheap. If I got resistors to bring my power to 11A
> on the one side and 5A on the right, then set my
> pots to .4V would that work??? Thanks so much for
> your help.

Edited 1 time(s). Last edit at 08/25/2013 11:07AM by luigi.

nibake,

I found my 16 amp supply to not be enough for my printer and I am running a standard set up without any lights or other things like that. I don't even has an LCD on my ramps. I had to add a second supply before my printer started running right. You should probably read the PC Power Supply page and pay careful attention to the note about the high current connector on the ATX power supply. This should be on your 11 A part of the connector. I picked on of the main motherboard connector to put on my 5 A.

I would contact maker gear and see what v-ref they recommend for those motors. If they are .5 amp then that is the amperage they were meant to produce their max torque at.

I'll read the wiki page. This is the power supply I am using [www.ebay.com]

Like i said your PSU wont be the problem,
Probably it just gets to much amps, and the settings accerlation might still be to fast,

But as colin said his ones are atm 10 000 hours of printing and no problems so i aint sure why i would need to bother,

The moters are 15 euro (20 dollar) so even if one breaks it isnt a big deal.

nibake Wrote:
-------------------------------------------------------
> I'll read the wiki page. This is the power supply
> I am using [www.ebay.com]

Hmmmm. I tried the settings that Startingtoprint had in his post and have my Y pot set to .10V and it feels cool after 1.5 hours of printing. I will have to set the rest the same. Unfortunately my print broke loose so no joy yet

nibake Wrote:
-------------------------------------------------------
> Great. I will check the PSU voltage. I have them
> all set to .4v and they still are getting quite
> hot. thanks for the help.

well when you go to low you might lose some steps,
please notify us what you are getting, if it works or not.

due mine are very hot, but i dont wanna change it due i dont want my prints to start failing at the end

X and Y are now running cool around .1V Z is slightly warm but definitely acceptable to me. I'm still tryin to tune the extruder. .1 was too low as it wouldn't move, but when I cranked it up it was scorching hot. I have a feeling it will still be the hottest of all the motors, but I haven't lost any steps yet. If I do, it will probably be at the end of a long print, hehe...murphy's law

hmmm wont be due to your power supply, i have my printer running on a 100amp power supply, It will only draw as much as it needs,


id be tuning the current, it needs to be less... I have my printing running like 10 hours a day, most of my motors are to hot to touch, i just cant be bothered tuning the current down to each stepper... mine have not fried yet, if they fry, ill then turn down the current and replace the motors... they are cheap

nibake, I'm sorry I didn't look at your link earlier. I too bought the 20 amp supply of this variety and this supply DOES cause issues. The one I have drops to 10.5 VDC when the heat bed kicks on. It may drop some before that, but I didn't test it. When my heat bed kicked on I could hear my fans slow down, so I checked it. This issue WILL throw off your stepper accuracy as well as temp readings from your thermostats and there for make your bed and more importantly your hot end temps off. Maybe yours is better than mine and doen't have this issue (they look exactly the same), but I would get your printer running full out an check the voltage at the supply. If it's not 12 this isn't good.

nibake Wrote:
-------------------------------------------------------
> I'll read the wiki page. This is the power supply
> I am using [www.ebay.com]

Just got the spec sheet for these motors from makerfarm. They are 0.5 amp motors. They were actually designed to be ran at 9.5 VDC, but that seems to be OK. My motors were designed to run at less than 12 VDC as well, but I think what seems to be important is that they were designed to handle 1 amp. So, setting my v-ref to 0.4 VDC runs them just fine.

nibake, I think you have it now. The spec sheet says they are 66 oz in (4.8 kg cm) motors and the were designed to produce that much torque at 0.5 amps. If you tune your v-ref to give them that much current, they should run your printer fine.

The spec sheet says the coils in those motors have a 19 ohm (give or take 10%) resistance. So, if you were running them with 9.5 VDC that would be 9.5 VDC / 19 ohms = 0.5 amps of current. Since you are actually running them at 12 VDC then 12 VDC / 19 ohms = 0.63 amps. You have to go below 0.2 on your v-ref because of this math.

Now let's look at this calculation again if your PSU is browning out and dropping 1.5 VDC. 10.5 VDC / 19 ohms = 0.55 amps. Your loosing 0.08 amps that's a 12 % reduction in amperage. This will make a difference in how your steppers move. It may be enough to make them skip, but I'm pretty sure it will be enough to make them not move accurately. Instead of turning the shaft 0.1125 degrees they may only turn it 0.099 degrees.

Now let's look at what happens if your PSU is producing too much voltage. 13 VDC / 19 ohms = 0.68 amps. Now your steppers are getting too much current and will run warmer. The higher the voltage the more current and the more heat. In your case though your PSU probably isn't running over and all the heat is due to double current.

Micro stepping is accomplished through fine control of current.

PSU VOTAGE IS IMPORTANT.

Edited 2 time(s). Last edit at 08/26/2013 11:26AM by appdev007.

glad to see you got it worked out nibake. good work.

If we are going to reserect a zombie thread ....

0.4V on the normal stepper controllers is a bit high. Something down in the 0.3 to 0.35 volt range is more rational for thes motors. There's a lot of math behind that which I can go into if you need it. The Z motors are running fine at your setting. They are wired in paralell, so they each get 1/2 the current of the other motors.

Here is a plan:

Pick a voltage like 0.3V for the X and Y
Set the Z axis to no more than 2X the Vref voltage of the X and Y motors or 0.4V which ever is *less* (two motors each with 1/2 share of the current)
Leave the extruder motor where it is for now.

Run some speed tests and see how it does. If there are skips, take the current back up. If not, try 0.25V. See how that does.

Once you have a valid voltage for the X, Y, and Z you can play with the extruder motor.

I use the same motors from Makerfarm and they were running way too hot (165 deg after a long print). I finally set the reference voltage on the drivers for X, Y, E to appr. 0.18V and to double that for Z (2 motors/one driver). Now the motors are running at 105 deg max and the best part, much of the noise and vibration is gone. Just smooth quiet printing. Setting the reference voltage is tricky as the smallest pot change will have big impact on motor amps.

Edited 1 time(s). Last edit at 10/31/2013 10:40AM by Threegreens.

A lot depends on how fast you want to run things. If you slow everything way down, it's nice and quiet. You can run lower currents. It just takes forever and ever to finish a print.

I dont understand some information posted on here,

the PSU does not matter that much unless it changes, it needs to be a stable voltage/current. My input voltage will be nothing like the output of the stepper drivers, its completely regulated
I have tried 12 to 18 volts, the output on the stepper drivers does not increase. Nothing changes, operation is the same

The heat is coming from to much current,
If you can't keep your steppers cool from tuning the current, for e.g. you turn it down and it skips, there is a chance your overloading them, you need air cooling, there is no way around this if their duty cycle is be pushing more than it can handle.



Connecting Brushless stepper motors in series i do not see to be a good idea, How do they stay synced ?

When you take your power supply from 12 to 18 volts, the heat in your driver chips goes up a bit. The heat in your motors should not change at all.

If the motors are properly designed, they are rated for something like 135C. That's hotter than your heated bed. Touch your glass plate, then touch your motor, which is hotter? In my case it's always the 90 to 110C heated bed, and not by a little. I run the manufacturer's rated current through my motors.....

The drivers used for reprap printers are constant current drivers, so you just need to tune the output current of the driver to match your motor specification (as long as it is not higher than the max rating of the driver). The motor voltage does not really matter, as long as it is lower than your power supply voltage (though lower voltage, and lower inductance motor will give the fastest stepping rates). Applying ohms law to calculate motor current based on applied voltage, and coil resistance does not work when using a constant current driver.

Motors will usually run quite hot, since there is a fair amount of power dissipated by them. For the motor being discussed, if each winding is running at full current, the power dissipation is 0.5A*9.5V*2 windings=9.5W. This will get it quite hot, but as long as it stays below the specified maximum temperature, it should be fine.

---

Mike Anton
[manton.ca]
[laserlight.wikidot.com]

ok so with this information,

im getting, Its fine if they run hot,

In my case, my X motor is screwed into PLA, mine runs hot, but not hot enough to melt out of the mount...
Since awhile ago, i fixed small fans on each motor making them run cool, its fine.

I do quite often change power supplies, Because i need them for other things, i never seem to have any issues with my motors, and mine are cheap ones...
I can imagine at speeds above 200mm's or moving large masses around, id quite possibly need larger motors. I never noticed my gen 6 board getting warm, its only because i have crazy cooling on everything.
My X and Y, Hotend heatsink and gen6 board all have cooling.

Edited 1 time(s). Last edit at 11/02/2013 04:12AM by nechaus.