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Author Topic: Can't get this hybrid stepper to run properly  (Read 4814 times)

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Offline geone

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Can't get this hybrid stepper to run properly
« on: May 18, 2011, 02:21:02 PM »
Howdy:
I am trying Mach3 to see if it will drive the hardware we are using.  As you might expect, we are having some problems getting started.  The main problem we are having is rapid movement and signal crosstalk.  The equipment we are using is new:

nema 34 hybrid stepper(s)  WT85STH151-3004A (bipolar) 1600 oz (Wantai motor)
2ph stepper motor driver(s) SD-2H086MB
24vdc/8.5amp power supply

We trying to develop a 4 axis prototype device with little experience in CNC hardware.  Our device has a requirement for rapid positioning and we cannot seem to achieve more than 200in/min  (500 steps/200in/min setting using the software [motor tuning and setup]).  Any step settings higher than that or in/min cause the rotor to chatter and become static and stop turning.  We have tried all combinations of dip switch settings (driver) and software settings (motor tuning) with the same results. 

Question:  Does the motor tuning in Mach3 negate the dip switch setting on the driver....must they be the same?  Thanks much for any suggestions.

nubie
geo

Offline Hood

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Re: Can't get this hybrid stepper to run properly
« Reply #1 on: May 18, 2011, 02:54:22 PM »
Question:  Does the motor tuning in Mach3 negate the dip switch setting on the driver....must they be the same?  Thanks much for any suggestions.

nubie
geo


No, you need to tell Mach how many steps per unit and this is determined by the steps of the motor (Likely 200) and the microstepping you have the drive set to, also if you have any gearing between the motor and the output of the axis.

Hood

Offline ger21

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Re: Can't get this hybrid stepper to run properly
« Reply #2 on: May 18, 2011, 05:28:23 PM »
You'll never get that motor to spin very fast on 24V.

Typically, the larger the motor, the slower it's max usable rpm.

Geckodrive has a formula for power supply sizing, for maximum motor performance. 32 x square root of the motor's inductance.
For your motor's, to get maximum performance, you'd need to supply them with about 150V, about 6 times what you have. Since usable rpm is proportional to voltage, you're basically only getting 1/6 the maximum rpm that that motor is capable of.

You might want to try a 72V power supply, which should be 3 times faster. Better still might be to gear up, so that the motor spins slower while moving the machine faster.
Gerry

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Re: Can't get this hybrid stepper to run properly
« Reply #3 on: May 18, 2011, 10:39:19 PM »
Or, better still, get a servo motor.  A stepper turning at high RPM will have very little torque....  And with steppers, the larger the motor, the worse it will be at high speed.

Regards,
Ray L.
Regards,
Ray L.

Offline geone

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Re: Can't get this hybrid stepper to run properly
« Reply #4 on: May 19, 2011, 01:52:59 PM »
Thanks to all for your input...I guess geared belt drive will be my best solution since I have 4 of these guys..
regards
geo

Offline RICH

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Re: Can't get this hybrid stepper to run properly
« Reply #5 on: May 19, 2011, 09:15:15 PM »
Do you have a motor curve for the motor?
I couldn't find that motor on the site.
RICH

Offline geone

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Re: Can't get this hybrid stepper to run properly
« Reply #6 on: May 20, 2011, 01:05:00 PM »
I don't have one, but I think I can get one....send it to you when I get it
thanks
geo

Offline geone

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Re: Can't get this hybrid stepper to run properly
« Reply #7 on: May 22, 2011, 11:43:55 AM »
no luck on the motor curve...thanks anyway.
geo