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Problem with stepper motors (have looked through archives)
« on: April 10, 2009, 03:24:09 PM »
Okay,

I am running a Gantry router with just starting set up. The problem is that the motors are not moving and having a problem with the tuning them to get them running. I am getting sound from them but no motion. Sound changes when I change settings in either Mach3 or on the board switches so that is good. Wiring on the step motors is two centre taps attached to two pairs (two groups of three) and are wired as shown on diagram provided by maker with a 1.5 ohm 50W resistor inline of each centre tap and running 5V for logic and 12V for the combined XY with a separate 12V for the Z. The maker provided one to be used with both tap wires at 5V. All four are mounted to a metal base with thermal paste and three heat sink blades are on top of them.

PIN2 = X Direction
PIN3 = X Step
PIN4 = Y Direction
PIN5 = Y Step
PIN6 = Z Direction
PIN7 = Z Step

Active Lo is enabled. When I have the system running can still turn the arbour of the stepper motor. When power is off can also turn them and turns arbour as well. I have tried the 500, 50, 5 setting on the tuning controls with no results. Have read through the posts with alot of information gotten (thanks to all who answer them) but no joy in movement on them the number on the side of the steppers is 23HS8603 and all bear the same numbering set.

So any ideas on what can be done to make the motors work?? System is running of both a laptop and a desk top with the same problem. So, please help. this is going to be helping with production of musical instruments for a client and really need to get it working.

Thanks,

Michael

Offline Hood

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Re: Problem with stepper motors (have looked through archives)
« Reply #1 on: April 10, 2009, 03:47:19 PM »
What make of drives?
Hood
Re: Problem with stepper motors (have looked through archives)
« Reply #2 on: April 10, 2009, 04:51:00 PM »
Stepperworld FET3 Dynamo Board which is a three in one board with MOSFET on all three axis. Hope that helps a bit.

Michael

Offline Hood

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Re: Problem with stepper motors (have looked through archives)
« Reply #3 on: April 10, 2009, 06:10:17 PM »
Not familiar with these drives, I will do a search later and see if I can find info on them.
Hood

Offline ger21

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Re: Problem with stepper motors (have looked through archives)
« Reply #4 on: April 10, 2009, 07:49:49 PM »
When the drive is powered up, the stepper shafts should be "locked". If not, than you have a wiring or drive problem.
You probably don't want to hear this, but the Stepperworld drives are not the best choice for a router. They're inefficient, and not capable of very high speeds. When you get it working, you can get better performance by increasing the supply voltage, but you'll need bigger resistors which will create a lot of heat.
Gerry

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Re: Problem with stepper motors (have looked through archives)
« Reply #5 on: April 12, 2009, 10:34:54 AM »
Okay,

Being that getting new drives wil take a bit of time from order to arrival is there any way of checking which is the problem and getting it fixed so that the system will work?

The Router will be cutting hard woods only to begin with and that is where I am sitting at right now. Having been able to do further reseacrch now that I know where to go looking. I would probably not have bought them and gone with a maker here in the UK, mainly to have local access.

So what needs to be done to get them online? Whether or not they are "good" motors or drives is of little importance at the moment. Finding away to get the system running so that i don't have to do all the work on the cuts by hand control (That costs alot of time and requires additional finish work to insure quality standards are met at the level they need to be.

Thanks for all the information and input. How can I go about checking them and getting the system and running. It came with one 1.5Ohm resistor to be used with 5V and states that the board can handle 12V no problem (the FET's are rated higher) the board is inside a aluminum box on whic the resistor are mounted by screws with thermal compound on their undersides and cooling blades on top. I have mounted a a heatsink on the sides of the motors as better safe than sorry. I am running 12V in the stepper mode and having no joy with tuning or getting the motors to move. They are making sound just not moving.

They will move under hand control both with power on and off. I have Lo active as it needed that just to get the motors to start responding somewhat is there additional information or pins I need to activate (There are options on the board for active lo settings but it is a single pin and does not tell if it is for step or direction or the schematics). So any help would be greatly appreciated. Saying that i have gone down a dead end , while might be acturate in some ways does not get a solution found.

Michael
Re: Problem with stepper motors (have looked through archives)
« Reply #6 on: April 12, 2009, 02:38:13 PM »
Hi Michael,

Does your BOB have a charge pump circuit that needs to be activated? Couldn't find any detailed info on the FET3 board so this is a shot in the dark.

Posted this in MYCNCUK too just in case you go there first :)

Jeff.
Re: Problem with stepper motors (have looked through archives)
« Reply #7 on: April 12, 2009, 04:06:58 PM »
Good News found the enable pin set and that is fixed bad news it still does not turn worth a darn and only nudges when I change direction. highest on current test was 500, 50, 7 with no go and that is almost a square signal so don't know Which way to go now on it and need to either pitch them and start manual cutting until a new board gets here that will handle the unipolar until I can upgrade to better (close the contract).

Oh, the cigar goes to Mach 3 yahoo group for old but good information if you mine for it with the right words.

Michael

Offline Jeff_Birt

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Re: Problem with stepper motors (have looked through archives)
« Reply #8 on: April 12, 2009, 04:24:43 PM »
I would start from the beginning and check everything.

1) Have ran the driver test? If so what does it look like? If it looks bad have you done the optimization?
2) Double check that you have the correct parallel port selected.
3) Measure the output voltage of the parallel port. Is it 5V? Some breakout boards will not work with newer 3.3V ports.
4) If you have access to an OScope check the pulse stream on each step pin on the parallel port. Some PCs will look OK on the driver test but the parallel port electronics can drive fast enough.

I don't believe that you have mentioned what steppers you are using. Do you have the full specs on them? A 12V supply is pretty low for steppers and will greatly reduce your performance and may not allow the stepper to develop full torque. If you can respond with the stepper specifications someone may be able to offer more advice.

Happy machining , Jeff Birt
 
Re: Problem with stepper motors (have looked through archives)
« Reply #9 on: April 13, 2009, 11:02:43 AM »
Have gotten Y and Z to move though Y is not moving it's full axis. So started double checking the frame and found loose bolts that I am now having the fun of truing the system and see if that brings the X online as well. Z was running smoothly at 400, 150, 5 and the unit is mm's. So going to try to get everything else trued and see if they will run better.

The Stepper are 23HS8603 and the sheet that came with them states 6.75V 1.5A per phase. Maker states that 5V is enough to drive them.

Any and all inpuit of the positive nature would be a great help.

Michael