universal motor speed control problem

Using Arduino Motors, Mechanics, Power and CNC
1

hi
I'm trying to control a universal motor i get this code but i cant understand it
i want to increase the rpm until the analog read get 4v or 5v etc

#include <TimerOne.h>
volatile int i=0;
volatile boolean zero_cross=0;
int AC_pin = 9;
int dim = 0;
int inc=1;
int freqStep = 75;

void setup() {
pinMode(AC_pin, OUTPUT);
attachInterrupt(0, zero_cross_detect, RISING);
Timer1.initialize(freqStep);
Timer1.attachInterrupt(dim_check, freqStep);

void zero_cross_detect() {
zero_cross = true;
i=0;
digitalWrite(AC_pin, LOW);
}

void dim_check() {
if(zero_cross == true) {
if(i>=dim) {
digitalWrite(AC_pin, HIGH);
i=0;
zero_cross = false; /
}
else {

i++;
}
}
}

void loop() {
dim+=inc;
if((dim>=128) || (dim<=0))
inc*=-1;
delay(50);
}

thank for reading

2

Where did you get this code? Its got some glaring problems like lack of volatile declarations.

Does it match your hardware?

3

the code is working very well but I'm facing problem to find a way to code the rpm speed when analogread get a value like 700 or 500 or 200
I want to increase the speed (rpm) until the analog read is (i) , its important to have a same speed (rpm) at any load

4

http://forum.arduino.cc/index.php?topic=398000.0

new code the same problem

5

Question: do you get any answer on questions about scripts here or are there here not people who know something about programming Arduino's?

6

khaldoon:
http://www.instructables.com/id/Arduino-controlled-light-dimmer-The-circuit/?ALLSTEPS

That is a light dimmer (resistive load).

Motor is an inductive load.

Post your circuit diagram.

If you want constant speed with varying load you will need a feedback mechanism.

7

Dece:
Question: do you get any answer on questions about scripts here or are there here not people who know something about programming Arduino's?

The issue is delivery of the question. The question needs to be adequately clear - easy to understand. The description must be coherent. For example, it's impossible for anybody to answer something if uncommented (and possibly erroneous/flawed) code is posted, and the question is about reading some analog value in which the code does not appear to involve a reading of an 'analog' value.

8

Yea ok, but newbees have the problem that they have a problem and don't know how to solve it, so they post what they have and want to learn what they did wrong. So it is logic that newbees don't have all the knowledge that it needs, otherwise they wouldn't ask for help.

Don't understand me wrong, i help people online to with their computer problems so i do understand the difficulties that we are facing sometimes with solving people their problems, but that is in a way the fun from it.

9

Boardburner2:
That is a light dimmer (resistive load).

Motor is an inductive load.

Ah, but its a universal motor (aka parallel wound), the field windings are snubbed by the
armature's low resistance (easy path for current changes), so normal dimmer circuits are typically
OK. One of the advantages of universal motors is the sensible power factor, as most of the current
is armature current and not very inductive (mainly resistive due to mechanical load).

An induction motor on the other hand is very inductive.

10

MarkT:
Ah, but its a universal motor (aka parallel wound), the field windings are snubbed by the
armature's low resistance (easy path for current changes), so normal dimmer circuits are typically
OK. One of the advantages of universal motors is the sensible power factor, as most of the current
is armature current and not very inductive (mainly resistive due to mechanical load).

An induction motor on the other hand is very inductive.

The bit i am trying to get at is the arduino kits use wall warts , these work ok for kits with small motors but when used for applications with more powerful motors they are not so good.

IME wall warts are not generally good for supplying motors.

EDIT

I am not sure any way from the description I understand what the OP is trying to do anyway.

11

Boardburner2:
I am not sure any way from the description I understand what the OP is trying to do anyway.

This is the problem between the experienced user and the beginners on this forum. The beginner don't know what the experienced user want to read and the experienced user don't know what the beginner wants.

12

Boardburner2:
The bit i am trying to get at is the arduino kits use wall warts , these work ok for kits with small motors but when used for applications with more powerful motors they are not so good.

IME wall warts are not generally good for supplying motors.

EDIT

I am not sure any way from the description I understand what the OP is trying to do anyway.

Clearly you don't know what a universal motor is then!

13

MarkT:
Clearly you don't know what a universal motor is then!

I understand the concept of a universal motor also a stepper.
I am however perplexed by multiple failures of wall warts when used to power them.

When it comes to the control of universal motors however i do not fully understand the control technique.

MarkT:
, so normal dimmer circuits are typically
OK.

I have found this works ok with linear transformers.
Many problems with chinese wall warts though.

By dimmer circuit i assume you are not referring to 50 Hz type mains equipment.

14

Universal motors are universally used as single-phase mains AC motors. Controlling these from
an Arduino is via opto-isolators, no high power involved on the Arduino side at all.

15

Apologies Mark, i totally misread the question.

Please ignore comments.