Motor shield V2 specification

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jonny3xx
 
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Motor shield V2 specification

Post by jonny3xx »

Hi,

the spec for the adafuit motor shield states max. current is 1.2 A per channel. I try to run two Sanyo Denki 103 547 52500 (2 phase serial biploar wiring) steppers with the arduino mega 2560 and the motor shield V2. The stepper has 0.7 A per phase. What exactly is referred to as one channel ? Provided one Stepper uses one channel this would mean I need 2x 0.7 A = 1.4 A per channel which is slightly above what the shield according to the spec can do. I put on approx. 5V by the power terminal blocks.

Gcode commands sent are not completely executed. Movement stops after approx. half the number of steps intended. (I do not yet apply any load). Please tell me whether the facts stated above can cause this behaviour. Do I need to use motors with no more than 0.6 A per phase and/ or do I have th choose a different power supply?

Thanks

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adafruit_support_bill
 
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Re: Motor shield V2 specification

Post by adafruit_support_bill »

I try to run two Sanyo Denki 103 547 52500 (2 phase serial biploar wiring) steppers with the arduino mega 2560 and the motor shield V2. The stepper has 0.7 A per phase.
Please post a link to the electrical specifications for the motor. 0.7A/phase is not the whole story. We need to know the phase resistance and the voltage you are using to power the motor. For more information, see this guide. https://learn.adafruit.com/all-about-st ... he-stepper
What exactly is referred to as one channel ?
1 full H-bridge. These can provide up to 1.2A continuous. But the actual current draw is determined by the load, not the driver. Your motor will use 2 channels - One per phase.
I put on approx. 5V by the power terminal blocks.
What is the current rating of the power supply?

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jonny3xx
 
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Re: Motor shield V2 specification

Post by jonny3xx »

Please post a link to the electrical specifications for the motor. 0.7A/phase is not the whole story. We need to know the phase resistance and the voltage you are using to power the motor.

Phase Resistance is 3.15 Ohms, see e.g.

http://www.rta-deutschland.de/pdf/103-54.pdf

What is the current rating of the power supply?
I actually use a power supply for a model train, stating 0 to 8V eff, 5VA. Behaviour of the steppers is similar for very low and quite high Voltage (approx. 6 V at the terminal power block,slightly less at the channels). What should the current draw actually be with the steppers carrying no significant load ?

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adafruit_support_bill
 
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Re: Motor shield V2 specification

Post by adafruit_support_bill »

Phase Resistance is 3.15 Ohms
This motor is not well suited for use with the V2 motor shield. At 5v, it will try to draw about 1.5A per phase. That is more than the shield can tolerate. Fortunately, your power supply can't supply that much current, so no damage has been done.
I actually use a power supply for a model train, stating 0 to 8V eff, 5VA.
5VA means that at 5v, it can only supply 1A.
Behaviour of the steppers is similar for very low and quite high Voltage (approx. 6 V at the terminal power block,slightly less at the channels).
This is because your motor is trying to draw more than the power supply can provide, so the voltage at the motor will drop.
What should the current draw actually be with the steppers carrying no significant load ?
Stepper motor current draw is related to supply voltage and step rate. Unlike a DC motor, the load is irrelevant.
https://learn.adafruit.com/all-about-stepper-motors

A motor with a 3.15 ohm phase resistance will require a constant-current "Chopper" drive such as one of the Synthetos boards for best performance.
https://learn.adafruit.com/all-about-st ... he-stepper

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