Pololu A4988 Error?

Hi All

I have 2 Pololu A4988 and two NEMA17 (Spec: 5V, 1.2A) but i can’t control them with 5V only with 6V but the motors are shaking…

What can i do?
I hava a RAMS 1.4 can it solve the problem and it would be enough 5V, 2A as power supply for the board?

Circuit:
drive.google.com/file/d/0B8pthQ … sp=sharing

Arduino Code:

[code]// MultiStepper.pde
// -- mode: C++ --
//
// Shows how to multiple simultaneous steppers
// Runs one stepper forwards and backwards, accelerating and decelerating
// at the limits. Runs other steppers at the same time
//
// Copyright © 2009 Mike McCauley
// $Id: MultiStepper.pde,v 1.1 2011/01/05 01:51:01 mikem Exp mikem $

#include <AccelStepper.h>

// Define some steppers and the pins the will use
AccelStepper stepper1; // Defaults to AccelStepper::FULL4WIRE (4 pins) on 2, 3, 4, 5
AccelStepper stepper2(AccelStepper::FULL4WIRE, 6, 7, 8, 9);
AccelStepper stepper3(AccelStepper::FULL2WIRE, 10, 11);

void setup()
{
stepper1.setMaxSpeed(200.0);
stepper1.setAcceleration(100.0);
stepper1.moveTo(24);

stepper2.setMaxSpeed(300.0);
stepper2.setAcceleration(100.0);
stepper2.moveTo(1000000);

stepper3.setMaxSpeed(300.0);
stepper3.setAcceleration(100.0);
stepper3.moveTo(1000000); 

}

void loop()
{
// Change direction at the limits
if (stepper1.distanceToGo() == 0)
stepper1.moveTo(-stepper1.currentPosition());
stepper1.run();
stepper2.run();
stepper3.run();[/code]

The A4988 is specified for 8-35 V motor power supplies. If I understand your post correctly, you are using a 5 V, 2A power supply, which is inadequate for even ONE motor. In full step mode, one motor will draw 2.4 amps from 5 V (1.2 amps/winding x 2 windings) and two motors require 4.8 A.

With higher voltage motor power supplies and if the current limiting feature of the A4988 is properly adjusted, less current is required from the motor power supply. However, for one motor the power supply still needs to be capable of delivering at least 1x, or better, 1.5 x the winding current.

Hi!

No, I have a good 5, 4A Power Supply, my problem is that my NEMA17 stepper motors are working with 5V, but my pololu A4988 can’t controll them with 5V, only if i use 6V… but in this situation my motors are shaking…

What can i do?

Use a power supply with at least 8V, 4A output or buy a motor driver that will work with a 5V power supply.

can i solve this problem if i use RAMPS 1.4?