Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: method13 on September 23, 2006, 12:48:47 PM
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Hey,
Can stepper motor over heat? and then miss steps?
The other thing is that I didn't make my machine like some of you I bought mine so I'm not too sure how things work in the other stepper Controllers, but mine gets very very hot too hot to touch is that normal? To me that doesn't sound normal.
What do you think?
Thanks,
Greg
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Stepper motors can get hot, some say too hot to touch is OK but I prefer them just a bit cooler ;) Are your motors hot all the time (even when idle) ? or just after a lot of use?
Check that the resistor for current limitation is theĀ correct value( on the Geckos) for your motors. Also check that the voltage is right, it should be no more than 20x your motors rated voltage but also it must be under 80v for the geckos.
Hood
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Hi,
Thanks for the timely reply.
The controller box is too hot to touch when idle but not the stepper motors, they are only hot after using them.
I left it on by accident over night and I am supprised that the box didn't catch fire thats how hot it was.
Would the resister have the ratings listed on them?
I will check the voltages like you suggested and post them here later but my machine is running right now so I will do it when it's done.
In my enclosure the machine, material, motors were all very hot, so I added fans to vent the heat and everything is much cooler. In the controller box I added vents and fans and so far it is cool to the touch.
I am using Mach2, I dropped my acceleration to 1.0 and my velocity to 1.0 so it wont miss steps for now, I will try to raise them to see when I get it to start to miss steps. The worst thing about low settings is that it pauses when contouring and the cutter is slightly burning the wood that I am cutting so I need to up the acceleration to so that won't happen.
I have Surestep stepper motors 276 oz-in, 2.8a, 1.1 ohms what settings should they be able to run at?
Thanks,
Greg
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The control box would get hot as the transformer is in an enclosed space, you have done the right thing by venting and adding fans.
The resistors will probably be the type with the colour code bands, for 2.8 Amp motors I would think you want approx 36K resistor which would have Orange Blue Orange as the first three bands. I dont see any resistors in your pic, they are possibly there and just that your pic is too small to see them, they should be across the current set terminal s on the Geckos. If they are not present you will be putting 7Amps to your motors and they will get hot.
I would also suggest you move to Mach3 as it is much better than Mach2 and you should see a performance boost, your computer however will have to be half decent. If you do go to Mach3 you can keep Mach2 installed and refer back and forward to it for the settings you will need to input for ports/pins etc.
Hood
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Hi,
Here are a few pics for you so you can see a bit clearly, even though I changed my acceleration and velocity down to 1.0 the z axis still screwed up when cutting the job I am working on right now. I dropped the acceleration to .75 to see if this wont happen anymore. The biggest problem is that the company I bought the machine from says it can run way faster than that. I don't see what the problem is?
Thanks,
Greg
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Unfortunately none of your pics show the connector on the geckos to see if there is a current setting resistor in place :(
I notice the capacitors are 35V but I cant see the transformer specs so I am presuming your geckos are only getting supplied with 35V or less which will not be the best for speed.
Hood
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Hi,
I have downloaded mach3 but haven't yet tried to convert the settings,so all I have to do is take the Mach2 ports and pins settings and plug them in to mach3 ports and pins settings?
Do steppers have a max amount of pulses that it can recieve? Could it be a setting that might be too high for the steppers that I am using? So if the feed is to high it tries to read more g-code and then starts to miss steps?
Thanks,
Greg
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You look in Mach2 and see what port is used, what pins of that port are used for which function etc and take a note of them. Then shut down Mach2 and open 3 and go into the ports and pins (from config menu) and enter all the numbers you noted from Mach2. You should then be able to run your machine on Mach3. You will also have to enter the motor tuning specs such as steps per unit, accel etc but you should get that from Mach2 also
Mach has a max amount of pulses it can send out (actually its the parallel port that has the max) but dont worry too much about this ;) Reading of the G code has nothing to do with the steps in the way you are thinking.
Do me a favour and look at the geckos and look at the terminals at the end and see if there is a resistor connected between the last two (the ones that say current set) if there is what are the band colours?
Hood
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The image is a little fuzzy but you can see the colours, is that what you were hoping to see? :-\
I am going switch over to Mach3 because again the z lost it position. You would think that changing the settings to move slower that it wouldn't happen anymore so that's why I think it's more thant the acceleration and velocity settings.
Thanks,
Greg
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That resistor is OK, its a 5 band code which works out to 36.5Kohm which is near enough.
You may need to mess around with your acceleration and velocity to find your sweet spot but going to Mach3 is the best way as its easier to set up and gives better results in my opinion. Just in case you didnt know there are videos on the downloads link at the top of the page, there is one on Mach3 setup which is well worth a look.
Hood
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Hi,
When somthing is grayed out and there is a check underneath it does that should I check that in Mach3? It is for active low.
Thanks,
Greg
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If its greyed out then I think it will be because its not activated. What setting is it? Worst that will happen if you check it in Mach3 is it will go the opposite of what it would if it was unchecked, just have the E-stop button close to hand ;)
Hood
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Hi,
I put in all the settings into Mach3 and it moves on the scree but not on the machine, any tips? Is there any comon things that people miss that usually cause Mach3 not to work. I plan on watching the video again, the first time thru over I missed a few things but now that I actually touched the Mach3 interface I think I can just play with it and figure it out. The other thing is that the my machine make doesn't suggest Mach3 because they say it's not stable enough and it has some bugs.
Thanks for the help and I will be back on tomorrow to let you know how it's going.
Thanks,
Greg
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Mach3 is just as stable if not more so than Mach2 and it is a lot more powerful and adaptable, the makers are just too frickin lazy to set things up on Mach3 ;)
Do you have the port address set up properly on the ports and pins page? do you have the axis checked?
I am leaving for work soon so try a few things out and if you get stuck I am sure others will help you get sorted.
Hood
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Hi,
The one thing Mach could have done to make things is to make the setting page the same so it would be easier to convert over, they took three pages of input data and put it into one page and same with the output. I know it has more features so I am looking forward to switching over. Thanks for your help.
Greg
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its a long time since I used Mach2 so I cant really remember the layout but I do remember thinking that it was set out a lot better in Mach3 with all of the common settings grouped together. The latest release of Mach3 again has grouped the Logic and State pages together under a General Config title, this again is IMO a good move :)
Hope you get set up easily but if your Z is still missing steps check to make sure there is no binding anywhere.
Hood
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Hi, I've been wracking my brains on your problem, and discounting any problem with your computor port voltages if the missing steps happen on all of your axis and not just one the problem may lie with using a single power supply with all axises/axis (plural). As you have capacitors rated at 35v your power supply must be lower than this.
Also does the power-supply supply enough current when all drives are running at max stepping speed?
The way to sus this will be to measure the supply voltage when all drives are active but not stepping, then run a program that uses all the drives and ramp up the stepping speed. If the voltage drops then youv'e maxed out the current capability of the supply.
To get really good stepping rates with stepper motors, a supply of 75 volts is required.
John
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Hi John,
Where should I check on the stepper driver for the DC voltage? Should it be 75 volts per axis?
I'll give it a try and let you know what I got!
Thanks every bit helps, we are going to get this problem licked!
Thanks
Greg
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Very much doubt if you will have 75V, the voltage should be checked after the regulator or where it connects to the Geckos, it is DC. I think with a setup like yours it will probably be around 25 to 35 V, going higher would do no harm but would involve getting a new transformer and capacitor so its not the easy option and what you have should suffice.
Hood
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Hi, Hood is right. Although a power supply of 75v would be better, It seems by your explanation in the email this will not sort your problem immediately. You said that when the axis miss steps the steppers moan.
Are you saying that when the problem occurs, all the axises stop at the same time (for how long) and then start working again normally? This is the big question because if that is so we can eliminate some of the things it might be.
Your port and baud settings are OK. As are the current resistors. The mounting of the Gecko units should be OK for steppers under 3amps although heat transfer paste between the Gecko unit and the mounting would be better in the long term if you are using the machine all day every day. But don't worry about this for now.
Shielded cable has the earth/ground wire on the outside of all the other wires made like a lattice (similar to TV aerial cable or audio cable)
It acts like a Faraday cage and keeps stray signals from getting in or out of the cable long it's length. All of your signal wires should be shielded ( wires to the computer and the step and direction on the gecko's)
I hope I've answered most of you questions but to get back to the problem I need a better explanation of this moan from the steppers or perhaps a video of this problem happening.
Does the moan sound like a low vigorous hum?
Regards
John
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Hi,
Can you tell me what to check on the gecko driver in this picture, I mean I want you to tell me where put the one end of the multimeter, Put it here on (blank) and the other end on (blank) and you should get this voltage. ;D
Thanks,
Greg
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Put your Negative lead on the gecko Power Ground pin and your positive on the 24-80 VDC pin. I watched the video, sounds like you are trying to run it too fast to me.
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Hi,
The voltage for the stepper drivers while running is 35.2v. its the same while idle.
If I am running it to fast why does the K2 website say I can run it at 150 ipm? ???
This is a very weird problem because it will run just fine for one program and not for an other, what should I set my velocity and acceleration at? I have dropped it very low before and it still kept messing up?
Thanks, :P
Greg
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Hi Greg,
I have sent you a personal message.
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Hi,
I talked to Chaoticone and he gave me some great advice, we talked quite a bit about many possible problems and I think we have a good handle on what the problem is. We will have to see, I have to run some more programs to see if it has stops freezing up and missing steps.
Thanks for the help ;D
Greg