Is the motor destroyed ?

Hi . I wanted to know if a stepper motor with these problems has burnt : (?) And thanks in advance . 1- Multimeter doesn't measure any resistance between any of the 2 wires (bipolar) 2- Doesn't spin when I use an L298N (similar to http://www.geekonfire.com/wiki/index.php?title=Dual_H-Bridge_Motor_Driver ) with the connection method on that page and the following code :

int ENA=2;//connected to Arduino's port 2
int IN1=3;//connected to Arduino's port 3
int IN2=4;//connected to Arduino's port 4
int ENB=5;//connected to Arduino's port 5
int IN3=6;//connected to Arduino's port 6
int IN4=7;//connected to Arduino's port 7

void setup()
{
 pinMode(ENA,OUTPUT);
 pinMode(ENB,OUTPUT);
 pinMode(IN1,OUTPUT);
 pinMode(IN2,OUTPUT);
 pinMode(IN3,OUTPUT);
 pinMode(IN4,OUTPUT);
 digitalWrite(ENA,HIGH);//enablae motorA
 digitalWrite(ENB,HIGH);//enable motorB
}
void loop()
{/*In the way of 4 beats to drive the stepping motor,A group connected to motorA,B
 B group connected to motorB,Suppose A representing the forward current of A group,
 A- representing the reverse current of A group,B representing the forward current of B group,
 B- representing the reverse current of B group.
 this way run as follow:
 AB    A-B    A-B-   AB-
 or
 AB   AB-    A-B-   A-B
 */
 digitalWrite(IN1,LOW);
 digitalWrite(IN2,HIGH);
 digitalWrite(IN3,HIGH);
 digitalWrite(IN4,LOW);
 delay(10);
 digitalWrite(IN1,LOW);
 digitalWrite(IN2,HIGH);
 digitalWrite(IN3,LOW);
 digitalWrite(IN4,HIGH);
 delay(10);
 digitalWrite(IN1,HIGH);
 digitalWrite(IN2,LOW);
 digitalWrite(IN3,LOW);
 digitalWrite(IN4,HIGH);
 delay(10);
 digitalWrite(IN1,HIGH);
 digitalWrite(IN2,LOW);
 digitalWrite(IN3,HIGH);
 digitalWrite(IN4,LOW);
 delay(10);
}
  • I have tied arduino's GND with the power supply's GND (on a breadboard) Thanks in advance .

Hi, sounds like it if it has failed the a resistance test, do you have a part number. Can you post a picture of it.

Please read.

http://forum.arduino.cc/index.php/topic,148850.0.html

Tom...... :)

Why are you asking this ? (did you try running before and something happened ?) (if so , how did you try testing it when something happened ?)

Arman5592: 1- Multimeter doesn't measure any resistance between any of the 2 wires (bipolar)

Do you mean that the resistance is 0 ohms (which is what I understand by not any resistance) OR Do you mean that there is infinite resistance

Have you the multimeter set to the correct resistance range - the stepper coils may well have a low resistance of only a few ohms.

There should be 4 wires. That gives 6 possible measurements. Can you list the number of ohms for each pair? 1 - 2 1 - 3 1 - 4 2 - 3 2 - 4 3 - 4

Post a link to the motor datasheet.

And as @raschemmel asks - Did it ever work? If so in what circumstances? What makes you think there might be something wrong with the motor (rather than the L298 or the code) ?

...R

Hi , thanks for the answers .
1- I’ve read the page you said , otherwise , how would I know about [code][/code] or other stuff they’d taught and I’ve used already ?
2- There are lots of codes on the sticker attached to it .
3- Attached is a JPG file containing the motor and a driver .
( the thermometer isn’t connected to the motor , the wires have been cut , but somehow still there )
4- I haven’t used this at all - but it’s not new , I’ve salvaged this
(once our refrigerator was making noise and when they came to repair it , turned out this was making the noise . But some professional told us it was OK )
5- I’m asking this to know if I have to go for a new stepper or would this work anyway ?
6- it is rumored the problem is from the mini-board inside this .
7- As I said , there are some info on the sticker . The info is : Panasoinc - FDQT26GE6 (next line ) 9.75V DC,3.25W in nom. (next line ) 197D4968G009 - Evap. (next line ) WR60X10307 - 62309ZT (R is flipped (trademark logo)) RU MADE IN (somewhere)
((hate advertising))
4 wires in this order (right to left) Red / Yellow / Blue / White
a spin-and-record-stiffness test was done and sounds like Red and White are pairs (leaving Blue and Yellow to be the other)
Thanks in advance everyone ! :slight_smile:

Robin2:

Arman5592: 1- Multimeter doesn't measure any resistance between any of the 2 wires (bipolar)

Do you mean that the resistance is 0 ohms (which is what I understand by not any resistance) OR Do you mean that there is infinite resistance

Have you the multimeter set to the correct resistance range - the stepper coils may well have a low resistance of only a few ohms.

There should be 4 wires. That gives 6 possible measurements. Can you list the number of ohms for each pair? 1 - 2 1 - 3 1 - 4 2 - 3 2 - 4 3 - 4

Post a link to the motor datasheet.

And as @raschemmel asks - Did it ever work? If so in what circumstances? What makes you think there might be something wrong with the motor (rather than the L298 or the code) ?

...R

The multimeter shows 0 . That's usually what he shows when the two "needles" don't have any contact with each other . The lowest range is 200 Ohms . There's also another range but no numbers - two ICONS , 1x diode schematic view on the left with a 90 degree rotated wifi sign (telemetry) XD ... makes no sense ... I haven't measured all 6 combinations , I just put the black needle on one wire and placed the red on another , said 0 . Then put red on the next wire , said 0 . Then the next , 0 . Then I changed the black and tested more combos . 5 combinations . The spin-and-measure-stiffness test leads me to the fact that red and white make a pair and blue and yellow make another . Found no datasheet . Only thing I know is that after some google searches and trial and errors , the model is Panasonic FDQT26GE6 stepper motor (QT series) (for refrigerator) Only page about these : http://industrial.panasonic.com/ww/i_e/25000/ALE1000_e/ALE1000_e.html

And as @raschemmel asks - Did it ever work? If so in what circumstances?

Are you avoiding this question for some reason ?

Arman5592: The multimeter shows 0 . That's usually what he shows when the two "needles" don't have any contact with each other .

When the multimeter probes are not touching each other, or anything else you have infinite resistance.

What reading does your multimeter give with the 200 Ohm setting when you touch the two probes together? Do you have a low ohm resistor of known value that you can use to check the multimeter?

I haven't heard of a "a spin-and-record-stiffness test". Do you mean testing the ease of rotating the shaft when different combinations of wires are connected together? If it made a difference having some of the wires shorted together it suggests the motor is fine and the multimeter may not be functioning.

I don't think there is much scope for progress until you verify that your multimeter works properly - or buy a new one.

...R

JohnLincoln: Do refrigerators really have stepper motors?

They use them to get nice thin scrapings from the butter when it is rock hard.

...R

raschemmel:

And as @raschemmel asks - Did it ever work? If so in what circumstances?

Are you avoiding this question for some reason ?

Of course not ! I'd appreciate any help . Well yes , it has worked . In the refrigerator . Then it was making 'sounds' so it was replaced . Sound doesn't matter in my project so it's useful (unless it's destroyed)

Robin2:

Arman5592: The multimeter shows 0 . That's usually what he shows when the two "needles" don't have any contact with each other .

When the multimeter probes are not touching each other, or anything else you have infinite resistance.

What reading does your multimeter give with the 200 Ohm setting when you touch the two probes together? Do you have a low ohm resistor of known value that you can use to check the multimeter?

I haven't heard of a "a spin-and-record-stiffness test". Do you mean testing the ease of rotating the shaft when different combinations of wires are connected together? If it made a difference having some of the wires shorted together it suggests the motor is fine and the multimeter may not be functioning.

I don't think there is much scope for progress until you verify that your multimeter works properly - or buy a new one.

...R

Exactly . When they don't touch it's 0 in the sense of infinite . When they touch some 0.X numbers appear . The fact that the multimeter doesn't show exact numbers is beyond doubt - It has to be calibrated once a year whilst it has never been calibrated since bought (6 years ago) Yes , the spin-and-record-stiffness is to check if turning the axle gets harder/softer when wires make shorts . Mine became softer when red-white made shorts (as well as yellow-blue) I don't know how to calibrate multimeters . Perhaps Diode+telemetry sign is how I should . I'll search Google about that .

JohnLincoln: Do refrigerators really have stepper motors?

Or is it some other type of motor?

A 4 wired motor with multiple coils and a ceramic end so doesn't get hot , got passed all tests related to being steppers and is defined as a stepper on it's website . This isn't the main motor , as replacing it was way cheaper than what I think replacing the main motor would cost .

Robin2:

JohnLincoln: Do refrigerators really have stepper motors?

They use them to get nice thin scrapings from the butter when it is rock hard.

...R

Perhaps that's why there was a butter knife on it when it came out of the refrigerator ! XD

You have a meter that shows 0 for open circuit? That's a very unusual meter and misleading. 0 ohms is a short circuit in most peoples mind. (the exact opposite of open circuit)

A little knowledge ia dangerous thing. I think we're getting bad INTEL.

Arman5592: Well yes , it has worked . In the refrigerator .

Strange as it may seem that is one thing we all knew. You were being asked if it ever worked with your Arduino - try to give helpful amswers.

Yes , the spin-and-record-stiffness is to check if turning the axle gets harder/softer when wires make shorts . Mine became softer when red-white made shorts (as well as yellow-blue)

I expect that the motor (any electric motor) would be harder to turn when the coils are shorted - not easier. I just tried this with one of my stepper motors and I was quite surprised by how much harder it was to turn when either coil was shorted - just turning the shaft with my fingers.

I wonder is it possible there is already a short inside your motor so that causing an external short circumvents the effect - I can't really see how that could happen.

Buy a new motor. Then when you have a motor that behaves properly - with suitable code and a suitable power supply - you can test the doubtful motor with more confidence. Trying to learn about stepper motors and trying to debug possible motor faults at the same time is just too complicated.

...R

Obviously the windings can't be OPEN if shorting the wires changes the turning resistance. As I said, I think we are getting some bad intel. Someone needs to resolve this whole winding resistance issue because it is obvious the OP doesn't know how to measure resistance. (based on the statement that the open windings read "0" on the meter.)

FYI, "0" resistance = continuity (as in , a wire)

raschemmel: (based on the statement that the open windings read "0" on the meter.)

Alas, life is not so simple. I have three cheap multimeters. The two manual ones show a 1 on the left of the screen to mean open circuit but the auto-ranging meter shows 0.L to represent an open circuit. All three of them measure resistance correctly.

...R

Do you agree that the windings can't be open if shorting them creates resistance when you turn it ? Can we agree on that ?

If you were to measure resistance of a motor using a scale in Megohms, then it's likely it will show as closed circuit. This could be what is happening. Since multimeters measure resistance using a DC current, it would be normal to find an exceedingly low resistance.

raschemmel: Do you agree that the windings can't be open if shorting them creates resistance when you turn it ? Can we agree on that ?

I agree with you - that was my experience. But the OP said

Mine became softer when red-white made shorts (as well as yellow-blue)

I don't have a theory that is consistent with that.

...R

All - based on my research on the part # supplied - I am not sure that this motor is a stepper motor; I believe it may be a standard DC motor with a PWM sensor; two of the wires are for power, two are for the sensor. Basically, I googled the # supplied (FDQT26GE6 ) which gave me this link:

http://www.appliance-parts-usa.com/G-GE-Refrigerator-Evap-Fan-Motor-WR60X10185-panasonic-UDQT26Ge4-C3B0_p_2323.html

Since it is a GE motor - you can then google the second number shown (WR60X10185). The google results seem to indicate that it is a DC motor with a PWM sensor...

Maybe I am wrong, but I have never heard of a home appliance using stepper motors (computer peripherals like scanners and printers, certainly - but not a refrigerator or the like)...

cr0sh: All - based on my research on the part # supplied

Sounds more logical than a lot of the other stuff here.

If true it should be simple to test the motor by connecting a battery to the motor power connections.

And the noise that signalled the demise of the motor in its orginal role might be worn out brushes - which would also account for the open-circuit.

...R