Getting the 5-phase stepper to run.

Recently I bought three stepper motors from a junk seller in ‘armour street’. It costed me Rs. 300 each. The labels on these motors were almost unreadable, but since I selected all three motors of the same type I was able to put the remaining contents of the labels to find out about the motors.

The labels stated the following.

5-PHASE STEPPING MOTOR
A5729-9115FV
DC 2.0A 0.347 OHMS / PHASE
0.72 * / STEP
FC6-0435 02
ORIENTAL MOTOR CO LTD

Each motor has 5 wires coming out, and by disassembling one motor I found it was wound in a penta wiring (All coils are connected end to end to form a pentagon).

The next job was to get the motor to spin. I searched the web for an appropriate controller but couldn’t find any that satisfied my need. So I decided to build my own.

I found the energizing sequence here.

I thought of using a PIC16F84 (since I had experimented with this chip and had one in my parts box) as the controller and five IRF540 s and five IRF9540 s as the driver MOSFETs.

I wrote the following code in C in order to spin the motor in a single direction. (My intension was to some how get this motor working)

#define __16f84

#include"pic/pic16f84.h"// Set the __CONFIG word:

typedef unsigned int word;

word at 0x2007  __CONFIG = 0x3ffa;

const unsigned int excitations[] = {22,18,26,10,11,9,13,5,21,20};

signed char excitation_index = 0;

 void forward(void){

 // increment the index;

 excitation_index++;

 PORTB = excitations[excitation_index%10];

}

void main(void) {

 TRISA = 0x00;

 TRISB = 0x00;

 PORTA = 0x00;

 PORTB = 0x00;

 T0CS = 0;

 T0IE = 0;

 GIE = 0;

 PSA = 0;

 PS0 = 1;

 PS1 = 1;

 PS2 = 1;

 T0IE = 1;

 GIE = 1;

 while(1){

 	// increment port a to indicate that the chip is doing it's job.

 	PORTA = PORTA + 1;

 }

}

void intr_handler(void) interrupt {

 T0IF = 0;

 GIE = 0;

 forward();

 GIE = 0;

}

I used the SDCC compiler for GNU/Linux to compile and used PIKDEV to burn the hex file to the chip. PIKDEV failed to verify the chip after burining the hex, so I switched to Windows and used ICProg to burn the chip which was successful.

The following is the basic driver schematic I used to run the motor.

The Port B’s B0-B5 are connected to 1-5 in the diagram respectively. The motor connects to A,B,C,D,E points in the schematic.

I setup my proto board and powered it up with a 300mA power supply. It didnt work as expected. The motor kept vibrating without turning. After hours of checking what was wrong I figured out that the power was not enough to drive the motor.

Then I used a 1000mA 12V power supply to power the motor and the 300mA 12V to power the uC board.

The motor started to spin with very low torque and very low speed. Also about 2 of the IRF540N s were getting hotter than the others. The investigation is pending.

I think thats because there is no PWM used in this driver. Planing to add a PWM to this driver as the next modification.

By the way I destroyed 2 PIC’s in the process, one by applying 12Volts to PORTB and another by burning the hex file on to it too many times. ( I had used it for about more than a year and I suppose it went out of the maximum number of times it could be reprogrammed ). Any way I finally got the 5-phase to run. 🙂

See it working in the following video. Sorry about the very bad quality.