24V DC miniature motor on AC 220V

[me_guitarist]

How r u guys!!!
Can I use 4 x 1N4007 to make a rectifier,use some zener diode & resistor to reduce the voltage, and run the 24V DC miniature motor on 220V AC?
How to do that? Any ideals?


Thnaks In Advance

 

[dindeds]

Running small 24v DC motor off 220V mains is not preferred due to large waste of energy lost in the circuitry (voltage dropper).
Usually the following circuit is used, it's safe and almost negligible power lost.

 

[me_guitarist]

Dear dindeds,
thanks for yr ideals,but I need a compact converter,coz a transformer can't feed into my design.

 

[IanP]

If the micromotor requires less than 100mA you can build transformerless power supply .. see example below ..
ZD3 = 24V ..
Mere details at:
**broken link removed**

Regards,
IanP

 

[me_guitarist]

Dear IanP,
Thanks for the diagram.
I'll work it out & post the result.

 

[me_guitarist]

Dear guys,
I tried the circuit & replaced the FR & R1 with 5w1K2 coz I cant it, the 5w1K2 resistor result in very hot temp & smoked, what is the problems?

Added after 2 minutes:

how to solve this problem?

 

[IanP]

What is the value of C1?

Regards,
IanP

 

[me_guitarist]

4.7uF 450V

 

[Jepeto]

As dindeds wrote “large waste of energy”

 

[me_guitarist]

E-cap

 

[Jepeto]

Dear guys,
I tried the circuit & replaced the FR & R1 with 5w1K2 coz I cant it, the 5w1K2 resistor result in very hot temp & smoked, what is the problems?

Added after 2 minutes:

how to solve this problem?

As dindeds wrote “large waste of energy”
You should calculate the power and use proper power resistors and verify the resistors are for high voltage

 

[me_guitarist]

but my design space is limited

 

[Jepeto]

What about SCR I’m not experience with this components but I think it will help you to reduce the voltage saving space and energy

 

[me_guitarist]

what 'Gate logic control circuit' mean?

 

[IanP]

First of all, 4.7µF is just to big ..

In the original circut 90% of the total voltage drop was across C1 and 10% across R1 ..
If you increased the value of C1 by 10 times you have to decrease the calue of R1 by the same ratio ..
After all it's role in this circuit is not changing power into heat but protect the ciruit in the case of a short circuit ..

Now, if you follow the above, having this "big" 4.7µF cap, you may burn one or both zener diodes and destroy the rest of the circuit ..
Power rating of zeners should ensure that even without any load they are able to take all current ..

Do yo know how to calculate the required value of C1?

Regards,
IanP

 

[Jepeto]

The Silicon-Controlled Rectifier (SCR)
https://www.allaboutcircuits.com/vol_3/chpt_7/5.html

Silicon-controlled rectifier
https://en.wikipedia.org/wiki/Silicon_Controlled_Rectifier

https://en.wikipedia.org/wiki/Voltage_regulator#SCR_regulators

**broken link removed**

 

[me_guitarist]

I don't know how to calculate value for C1, infact I'm just a beginner on electronics........I used 0.47uF 350V the resistor get smoked also.

 

[IanP]

You are not telling the whole truth ..

If C1 = 0.47µF the maximum current will NOT burn any resistor of almost any value .. 5W ???

Zc=1/(ωC) ..

Regards,
IanP

 

[me_guitarist]

I use 2W resistor,maybe I wrongly put the value...sorry

 

[roykyn]

use a 12-0-12...transformer....eventhough it is not an efficient method....but it is safe cos it limits power and risk of short circuit or electric shock....