What is electrical component is needed to reduce the output voltage from 24vac down to 6vac

Thread Starter

HaKDMoDz™

Joined Dec 25, 2022
2
Hello All,

I have a wall adapter that outputs 24v AC and a small motor that requires 6v AC what resistor value is required for this voltage, please?
Are resistors the same for AC as DC?
 

Dodgydave

Joined Jun 22, 2012
11,234
Ideally you need a different transformer, but to drop the voltage down for the motor, you need to know how much current it needs to work out what value and wattage.
You could use a capacitor in series with the motor .
 
Last edited:

Alec_t

Joined Sep 17, 2013
14,192
Using a resistor to drop voltage to supply a motor is not ideal because at start-up the motor tries to draw more current than when it is up to speed. More current drops more voltage, so the motor may struggle to get started.
 

Dodgydave

Joined Jun 22, 2012
11,234
Ok Alec_t, so a resistor is no good for this project thankyou, I will try find a better adapter closer to the voltage.
You can try a capacitor in series with the motor, like 1uF will give you a Resistance of about 3K ohms, 10 u F is 300 ohms, but like I said earlier you need to know how much current it needs.
 

MisterBill2

Joined Jan 23, 2018
17,736
A resistor for a fan can work, but it will waste power. The resistance will depend on the motor current draw when it is running. If you have an AC volt meter available the resistor value can be found in just a few steps.
If the label on the motor states the current then the resistor will only require a bit of simple math. The needed voltage drop is 24 volts-6 volts =18 volts. Resistor ohms = 18 volts/(motor amps). So if the motor draws 1 amp the resistor will be 18 ohms, if it draws 1/2 amp the resistor will be 36 ohms (not a common value) so you would use either 33 ohms or 39 ohms (common values)
 

PaulEE

Joined Dec 23, 2011
474
HaKDMoDz™, could you post an image of the 6 VAC motor?

I just want to make sure it is actually a 6 VAC motor, to be completely candid with you. I've never seen an AC motor with such a low operating voltage, although maybe it is some sort of RC car/plane motor or a special application I do not have experience with.

Actually, can you post image of the wall adapter as well?

As far as the brute-force answer to your question, a transformer (as mentioned previously) is used to step AC down to lower AC.
 
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