Powering Kemei Hair Trimmer 1.2V DC Motor Using 12V Charger—What Components Needed?

Hi, 
I want to run a small dc motor (which is operated on a 1.2v 600 mah cell battery)using 12v charger. Now the problem is that when i connect the motor to 12v,5v,3.3v the motor starts pulsing (i mean starts for 0.5 second and turn off for 0.5 seconds and the loop keeps on ), but when i connected 3.7v 18650 cell battery directly to it, the motor start to rotate at full speed furthermore i connected the motor to 5v power supply but again the power supply turns off and on again and again. last but not the least when i run the terminal of power supply to one of the terminal of motor due to sparking it start rotating normally, but without sparking it keeps on pulsing.
Kindly tell me how to run the motor smoothly and what components should be used ? basically I'm trying to power Kemei Hair Trimmer using 12v charger? please help me!!!!! I have attached the image of motor.

Akbar it would seem that your motor has some sort of overcurrent protection, if it did not have you would probably have burned it out by now.What you need to do is reduce the 12V to 1.2V.  This will mean using a regulator circuit and some other components, and doing some soldering. Also, depending on the current drawn by the motor, the regulator could get quite hot and need a heatsink (fins to keep it cool). You would need to use a meter for testing.It sounds like you do not have a lot of experience with electronics - let us know how confident you would be to do this sort of thing and we can maybe advise you further.Also, why are you trying to do this - has the original battery or charger failed?  Would it not be easier to fix that?

Hi David, yeah you are right i have no experience in the field of electronics as I'm a student of software engineering but I don't want to charger the trimmer every time so i decided to connect the hair trimmer to AC mains directly by using some sort of charger or adapter, Now a days, I have two adapters one is 12v/1A and the other one is 5v/2A, now i have successfully operated the motor on 5v/2A charger but speed was too high but configuring it by adding a resistor of 8.2 ohms 2W resistor in series of motor, the problem is solved. Is it a good solution? Can you suggest a better solution than this?  I also discovered that a 1.2v 600mA voltage regulator is available but its a smd component tps52003 which have input voltage from 2V to 5.5V. Motor is operated on 1.34v 0.5A. 

Hi David, yeah you are right i have no experience in the field of electronics as I'm a student of software engineering but I don't want to charge the trimmer every time so i decided to connect the hair trimmer to AC mains directly by using some sort of charger or adapter, Now a days, I have two adapters one is 12v/1A and the other one is 5v/2A, now i have successfully operated the motor on 5v/2A charger but speed was too high but configuring it by adding a resistor of 8.2 ohms 2W resistor in series of motor, the problem is solved. Is it a good solution? Can you suggest a better solution than this?  I also discovered that a 1.2v 600mA voltage regulator is available but its a smd component tps62003 which have input voltage from 2V to 5.5V. Motor is operated on 1.34v 0.5A. 

Akbar your 8.2R 2W resistor is a nice easy simple solution BUT it will dissipate nearly 2W in heat and run pretty hot, so you'd have to keep it away from anything that might melt (plastic housings etc).  You could use the easily obtainable LM317 regulator in TO-22o case to do this, it will give you a nice 1.25V output, almost exactly what you need.  It would still dissipate the same heat but you could put a heatsink (fins) on which would let it run cooler.  Here's a circuit:
And here's the pinout
If your resistor works OK and you can keep it  from melting anything with the heat, I'd stick with that.  There are things called switching regulators that can do this much more efficiently but they are a LOT more complicated.

Thank for your solution! David one more thing when i connect the 8.2 ohm resistor with motor, without load it run successfully, while with load its doesn't start, after reducing the resistance to 4.7 ohm or 3.3 ohm it starts (with load) successfully for three to four times (connecting and disconnecting) after that the motor doesn't start, and then after reversing the polartiy it starts and again i have to reverse the polarity, why this happens?  and the electronic shop is too far away from my house so it is difficult to buy LM317 sorry for that.

Akbar: I have bad news for you, it looks like you will need to make that trip!  What is happening is that the motor is a varying load, it takes more current when starting up or when trying to cut through those really thick hairs in your nose!  (No offence intended, I myself have reached the age where the hair stops growing on my head and starts growing in my nose and ears! I have one of those trimmers too!  :-)So a resistor will always be a compromise solution - too high and it will limit the current too much for starting and tough cutting, too low and it will increase the voltage on the motor considerably when it is off-load. The solution is a regulator, to regulate the voltage to the motor to a constant value.  but as pointed out above, a linear regulator still dissipates the excess power.There is another solution - using a switching regulator as I suggested earlier, but they are complicated.  Happily though you can get them pre-built - here is a line of them from Digi-Key - you could mail order them (hope the post office is closer than the electronics shop? :https://www.digikey.com/en/product-highlight/r/recom-power/r78-series

(The above is very much larger than actual size - they are not much bigger than a standard TO220)The "78" in the part name refers to the well-known and loved 78xx series of regulators, but they are linear, and will again dissipate heat, and you can only get them down to 5 V (the 7805) which is too high for you.These regulators come in various voltages too - down to 1.8V which would probably power your little motor directly, motors are not too finicky about the voltage they use, or you could put in a diode in series to reduce the voltage by 0.6V down to your desired 1.2V:
The data says variously 1A and 0.5A output, but I think even 0.5A would be enough for your purposes.  You can then use an input voltage anything from about 5V up to 30V.Cheers // David

No offence indeed , but mine one is a beard trimmer , although thanks for this pretty solution i think this is a perfect solution like No Heat Sink required and Input Voltage varies from 4.5V to 30V i like that, but the problem here is that its price is about 6.64 US Dollars in which i can bought a new trimmer! so considering the factor of money its too expensive solution. By the way i tried another adapter of 5V/0.6A and connecting it doesn't start while the current passes through the motor. 1.By rubbing the wire (positive or negative) to the motor's terminal, a small spark occurs and the motor starts to rotate,why this happens?. 2.If i use resistors as voltage divider, does it'll work? or the solution with LM317 is better one?

Akbar... Yes I know these things are cheap, so I'd question spending all this time just to avoid recharging.... anyway- Yes the switching reg is an ideal solution technically, just seems uneconomic...
- The LM317 solution is good but not perfect (due to the power dissipation) but it would be better than a resistor- Rubbing the wire to start the motor - this is probably because that adapter does not have quite enough power to start it, rubbing the terminal interrupts the current anc causes the motor to move just enough to start.If it works OK with a resistor, I'd stick with that.  cheap and simple.  And if anything goes wrong, as you say, just buy a new trimmer...

Akbar it would seem that your motor has some sort of overcurrent protection, if it did not have you would probably have burned it out by now.What you need to do is reduce the 12V to 1.2V.  This will mean using a regulator circuit and some other components, and doing some soldering. Also, depending on the current drawn by the motor, the regulator could get quite hot and need a heatsink (fins to keep it cool). You would need to use a meter for testing.It sounds like you do not have a lot of experience with electronics - let us know how confident you would be to do this sort of thing and we can maybe advise you further.Also, why are you trying to do this - has the original battery or charger failed?  Would it not be easier to fix that?Very Helpfull Information americanexpressconfirmcard.club

Of course to just avoid charging, but now i have ordered 2 pieces of  LM317  online and thinking to make a DIY Heat Sink and try  your mentioned solution. You really helped me, It means a lot, my knowledge has been increased somehow , THANK YOU very much for your time David ! 

Akbar, no worries, good luck with it, and let us know how you get on.Thanks // David