Motor DC 12 Volts problem when controlling using PWM from Arduino

Thread Starter

BramLabs

Joined Nov 21, 2013
98
Sir, i want to ask sir. I want to control motor DC 12 volt by using PWM from arduino. The circuit i'm using is as you can see below :
tes.PNG

And motor DC i'm using with is :

436584_20130225032151.jpg
The motor DC is not as big as can be seen in the picture. It's only 4 cm x 4 cm size.

What i want to ask is that, when i connect motor DC directly to the 5 volt supply, the motor is moving. But when i connect it using arduino as the circuit i've already attached, and apply 100% duty cycle of PWM or 50%, it can't move at first time. It needs 'help' to move first with my hand, and then the motor is working greatly like when i directly connect it to the 5 volt supply. How can this happen ?
It's like this motor when i'm controlling it using arduino, it needs like a 'STARTER' to move. But when i just connect it to the 5 volt supply, it works greatly, no need 'help' of my hand to get start.

I also attach the arduino ground, emitter of the transistor and 5 volt supply ground together.

Thank you sir for your help.
 

mcgyvr

Joined Oct 15, 2009
5,394
#1- Its a 12V motor so 5V isn't enough
#2-That motor has internal electronics also and the PWM causes that to not work properly.
Fans like that can only be powered with smooth DC voltage and not PWM DC
 

Thread Starter

BramLabs

Joined Nov 21, 2013
98
#1- Its a 12V motor so 5V isn't enough
#2-That motor has internal electronics also and the PWM causes that to not work properly.
Fans like that can only be powered with smooth DC voltage and not PWM DC
Thank you for your information sir.
What makes me confuse is that why can't it work and need 'my hand help' also when i'm using 100% pulse PWM. It's like a smooth DC voltage isn't it ?
And i'll try tomorrow using 12 V power supply. Thanks before for your information sir ^^
 

Thread Starter

BramLabs

Joined Nov 21, 2013
98
#1- Its a 12V motor so 5V isn't enough
#2-That motor has internal electronics also and the PWM causes that to not work properly.
Fans like that can only be powered with smooth DC voltage and not PWM DC
I try using 12 V supply and it works greatly sir when controlling it using PWM from arduino. And also when i apply 50% PWM it's also work greatly without any 'help' with my hand.

But still, i want to understand, why it didn't move when i applied lower voltage like 5 Volts or even lower T____T.
In my opinion, we need a starter circuit to make it move when the voltage applied lower than 5 Volts or below it. ahahaaha..

Thanks before sir !
 

crutschow

Joined Mar 14, 2008
23,527
To run it at a low voltage you may have to initially apply a higher voltage (higher duty-cycle PWM) for a few seconds to get it started and then reduce the voltage.
 

Thread Starter

BramLabs

Joined Nov 21, 2013
98
To run it at a low voltage you may have to initially apply a higher voltage (higher duty-cycle PWM) for a few seconds to get it started and then reduce the voltage.
Thank you sir for your information.

Is there any kind of circuit for giving a starter instead of using PWM as a starter ?

Thank you very much sir ! I really appreciate it !
 

shteii01

Joined Feb 19, 2010
4,647
But still, i want to understand,
The problem is that you purposefully mismatched the parts.
The manufacturer clearly stated what is needed to make their device to work properly. The key words here are: work and properly. You purposefully did not follow manufacturer's directions and, naturally, encountered a problem. Yes, you made the thing to work, but... now you are searching for additional circuit or circuits. If you had matched manufacturer's listed specifications, you would not have needed those additional circuits that you are now searching for!

I realize that you probably don't have 12 volt dc supply. But consider:
- the time you are wasting searching for the circuits to use your 5 volt dc supply
- the additional parts you will need to buy and ship to build those additional circuits
- the time spent on building those additional circuits
If you add all that effort together, it might be cheaper to just get a 12 volt dc supply, just like manufacturer told you on the label to use IN THE FIRST PLACE.
 

R!f@@

Joined Apr 2, 2009
9,682
Better to buy L298 H-Bridges
How is that Better for his circuit. H-Bridge is bi-directional. You wanna blow his fan, literally.

@BramLabs .
A 12V fan will not start at 5V easily. You need to rotate the fan manually to overcome the starting current it needs.
But I have used some fans ( 12V rated ) at 5V, it does start slowly. Most of them does not start. Some does. May be low current rated ones.
 

Thread Starter

BramLabs

Joined Nov 21, 2013
98
The problem is that you purposefully mismatched the parts.
The manufacturer clearly stated what is needed to make their device to work properly. The key words here are: work and properly. You purposefully did not follow manufacturer's directions and, naturally, encountered a problem. Yes, you made the thing to work, but... now you are searching for additional circuit or circuits. If you had matched manufacturer's listed specifications, you would not have needed those additional circuits that you are now searching for!

I realize that you probably don't have 12 volt dc supply. But consider:
- the time you are wasting searching for the circuits to use your 5 volt dc supply
- the additional parts you will need to buy and ship to build those additional circuits
- the time spent on building those additional circuits
If you add all that effort together, it might be cheaper to just get a 12 volt dc supply, just like manufacturer told you on the label to use IN THE FIRST PLACE.
Thank you sir for your information. I really appreciate it ^^.
Yeah, that was my mistake. I tried 12 volt dc supply and working with the PWM arduino and it worked greatly.
And as a human with big interest in 'electronics' >_<v, i'm kinda wondering why when i'm connecting it directly to the supply of 5 V and it works greatly, but when i'm using PWM of arduino with 100% duty cycle ( My thought that was the same as giving it 5 Volt from the power supply but the difference is i'm controlling it using transistor TIP 102 as a switch ), and it's not working.
I know that it would be much good if i follow the specification of the product. But when i made a mistake (giving with the 5 volt supply not 12 volt supply), the phenomenon showed up, and it was interesting to learn. ahhahaha....
My thought for this answer is that like this :

Connecting directly to 5 Volt supply :
hal.png

Connecting with the circuit i was using with ( controlling with 100% duty cycle of PWM using arduino uno ):
hal2.png
That was just my first thought. ahahahah..
How's that sir ?

Thank you before for your help ^^


How is that Better for his circuit. H-Bridge is bi-directional. You wanna blow his fan, literally.

@BramLabs .
A 12V fan will not start at 5V easily. You need to rotate the fan manually to overcome the starting current it needs.
But I have used some fans ( 12V rated ) at 5V, it does start slowly. Most of them does not start. Some does. May be low current rated ones.
Why should i rotate the fan manually as i already tried to starting current it need sir ? Was it because the current not flowing at the first place ( Because of the switching transistor needs time, while this doesn't happen when i'm directly connecting the motor to the 5 V supply ). Or any reason sir ? ahahaha.... I just want to understand this phenomenon, because it's interesting to learn ^^

Thank you sir btw for your answer. I really-really appreciate it ^^
 

R!f@@

Joined Apr 2, 2009
9,682
TIP102 is a darlington device. The transistor will drop ~1.2V so you will end up 5V - ~1.2V = ~3.8V maximum to the Fan. If you try a MOSFET then it might work or may be a normal 1Amp transistor might even work.
If you have a variable supply you can check with 4V to see if the fan starts to rotate.
 

Thread Starter

BramLabs

Joined Nov 21, 2013
98
TIP102 is a darlington device. The transistor will drop ~1.2V so you will end up 5V - ~1.2V = ~3.8V maximum to the Fan. If you try a MOSFET then it might work or may be a normal 1Amp transistor might even work.
If you have a variable supply you can check with 4V to see if the fan starts to rotate.
Based on my calculation ( of course with your assumption ), i'll get :

Ib = ( 5v - 1.2v [your assumption, the Vbe is 0.6v] ) / 1k ohm = 3.8 mA
And i look at the datasheet of TIP 102 :
sss.PNG

Still, it would give me the saturation region. And the transistor TIP102, will work like a switch ( not in active region, and also not in cut-off region )
 

shteii01

Joined Feb 19, 2010
4,647
Thank you sir for your information. I really appreciate it ^^.
Yeah, that was my mistake. I tried 12 volt dc supply and working with the PWM arduino and it worked greatly.
And as a human with big interest in 'electronics' >_<v, i'm kinda wondering why when i'm connecting it directly to the supply of 5 V and it works greatly, but when i'm using PWM of arduino with 100% duty cycle ( My thought that was the same as giving it 5 Volt from the power supply but the difference is i'm controlling it using transistor TIP 102 as a switch ), and it's not working.
I know that it would be much good if i follow the specification of the product. But when i made a mistake (giving with the 5 volt supply not 12 volt supply), the phenomenon showed up, and it was interesting to learn. ahhahaha....
My thought for this answer is that like this :

Connecting directly to 5 Volt supply :
View attachment 97612

Connecting with the circuit i was using with ( controlling with 100% duty cycle of PWM using arduino uno ):
View attachment 97613
That was just my first thought. ahahahah..
How's that sir ?

Thank you before for your help ^^




Why should i rotate the fan manually as i already tried to starting current it need sir ? Was it because the current not flowing at the first place ( Because of the switching transistor needs time, while this doesn't happen when i'm directly connecting the motor to the 5 V supply ). Or any reason sir ? ahahaha.... I just want to understand this phenomenon, because it's interesting to learn ^^

Thank you sir btw for your answer. I really-really appreciate it ^^
I believe part of the problem is the amount of current that Arduino board can source.
The label on your fan states that it can draw as much as 140 mA.
Arduino board can source only about 40 mA? maximum. Normally it is likely to source 10-20 mA.

That is why using Arduino boards for power is a Really Bad Idea. They simply do not have the power, they were not designed to be the power source. They really are CONTROL devices. You use them to control device. Use something else to power the device.
 

Thread Starter

BramLabs

Joined Nov 21, 2013
98
I believe part of the problem is the amount of current that Arduino board can source.
The label on your fan states that it can draw as much as 140 mA.
Arduino board can source only about 40 mA? maximum. Normally it is likely to source 10-20 mA.

That is why using Arduino boards for power is a Really Bad Idea. They simply do not have the power, they were not designed to be the power source. They really are CONTROL devices. You use them to control device. Use something else to power the device.
I didn't use arduino as my 5 volt power supply sir. I used external power supply like on the schematic at my first post.
And BTW , when i'm directly connecting to the 5 Volt supply, i'm connecting with 2 options. First, i'm experimenting with using arduino as a power supply, and the second i'm experimenting using external power supply. The first and the second works greatly. I know arduino can maintain current up to, yeah, just say 40 mA. But it's work. I've tried it.
So i think the problem isn't because of the arduino.
Thank you sir btw for your help ^^

This is the video when i'm connecting my fan using 5 Volt supply arduino. And it's work great without any STARTING problem.

 
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