I bought this gear motor :

https://www.aliexpress.com/item/DC-...32591788024.html?spm=2114.13010608.0.0.F8KInS

In the discription its written that the range of the voltage is 6V to 12V.
I tried to connect it to a 9V battery but it doesn't work. I tried to connect it to a 12V from the wall through an adapter and the motor spinned.

why's that ?

thanks!

 

Hmm... it claims 12vdc but describes it as a brushless induction motor?
Was the 12v wall adapter AC or DC?
Short out the motor terminals and try and spin it, although it may be hard with the gearing, if you can, compare it to not shorted condition.
Max.

 

Hmm... it claims 12vdc but describes it as an induction motor?
Was the 12v wall adapter AC or DC?
Max.

12VDC.

 

My experience with products out of China is that their product descriptions are worth zip. Nothing.

On the other hand, that motor casing looks like a thousand others that I have seen on a PM brushed motor. The plastic end cap. The bent metal tabs holding everything together.

You are sure the 9V battery was fresh? While common, they don't have much "juice" and may not have enough current available for the motor.

Can you measure the current drawn by the motor with 12VDC? Then you should be able to estimate the current drawn from the 9V battery. They can only supply around 20mA current usually. And they don't last too long.

Since it is a geared motor, it likely draws more current than if it was running freely.

 

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My experience with products out of China is that their product descriptions are worth zip. Nothing.

On the other hand, that motor casing looks like a thousand others that I have seen on a PM brushed motor. The plastic end cap. The bent metal tabs holding everything together.

You are sure the 9V battery was fresh? While common, they don't have much "juice" and may not have enough current available for the motor.

Its a new 9V battery from the package !

Can you measure the current drawn by the motor with 12VDC? Then you should be able to estimate the current drawn from the 9V battery. They can only supply around 20mA current usually. And they don't last too long.

Since it is a geared motor, it likely draws more current than if it was running freely.

I measured the current by connecting a DVM in series with the motor (unloaded, powerd up by the 12V from the adapter). The result attached

Can you please help me find a solution to the question of what battery to connect to this mottor (it should be loaded later off course) ?

 

Ok, so when I read your meter, I see the motor drawing 60mA. That may be too much.

Note that is also the running current. The start up current required may be much higher.

Have you measured the voltage of the 9V battery after you have tried to use it?

You might try 8 AA batteries. This would start out close to 12V and they supply more current than one 9V battery. You'd need a couple of holders, like this one although there may be less expensive ones available.

 

Ok, so when I read your meter, I see the motor drawing 60mA.

The meter is set on the mA range, so is the reading actually 0.06mA? I guess not, if the motor runs when showing that reading.

 

Measure the current when the motor is running on the 12v adapter, post a picture of your meter readings and connections.

 

This is the connection I made :

 

And here is the acctual circuit and the live measuring :
41.3mA

 

So it takes 41mA, your battery may not be powerful enough to give that amount.

 

So it takes 41mA, your battery may not be powerful enough to give that amount.

How much a 9V battery gives and which buttery should I use in order to drive this motor ?

 

If you want 9V, i would use a lithium battery, or nicads, what voltage do you want to use?

 

I want a 9V.
I need to build this circuit in order to operate the motor with a different rpm through PWM.

Why to prefer a Lithium one over Alkalain or something else ?

 

lithium or Nimh batteries have a higher amp capacity for small size, plus they can be recharged.

 

OK, I understand, can you please give me a link to a rechargeable one from ebay / aliexpress or from other worldwide shipping site ?

 

How much a 9V battery gives and which buttery should I use in order to drive this motor ?

Your motor current will depend on load, have you tried it with the anticipated full load, for LiPo batteries look on the RC supply sites, such as Hobby Wholesale, Hobby King US etc.
Max.

 

Your motor current will depend on load, have you tried it with the anticipated full load, for LiPo batteries look on the RC supply sites, such as Hobby Wholesale, Hobby King US etc.
Max.

lets assume the geared motor is fully loaded, how much current are you guessing it will take depending on the unloaded value I gave ?

In addition, what if I will replace the battery power supply, for now (just to check that the circuit is doing what it has to do) with a 12Vdc adapter 1mA ?
Does everything will be allright and my circuit and MCU won't be damaged ?
This is the shceme of my circuit (assume I replace the battery with a 12Vdc adapter) :

 

Yes your circuit will work fine with the 12V 1amp adapter, then if all is ok swap the adapter for the 9.6V or 12V lipo // nimhi battery.

 

OK thanks,
Can someone please explain me what this 1N914 diode between the + and the collector for ?
I've missed it for now but I have other diodes : 1N4007, 1N758A, 1N5402
Can I use them instead ? How can I know if I can / can't ?