How to drive a variable speed DC motor with 5 wires?

Thread Starter

lsheaf

Joined Jan 22, 2024
3
Hi guys,
I'm new to the forum here so hello everyone!

I'm trying to drive one of these motors from an air conditioning unit without the air conditioner's internal boards.
Does anyone have any ideas what each of these wires does? 61BIYtpNgnL._AC_UF1000,1000_QL80_.jpg
 

Reloadron

Joined Jan 15, 2015
7,523
You have what is likely an air conditioner fan motor. The motor requires several voltages and signals to run starting with a 310 VDC power supply capable of 60 mA or 13 watts. The 15 VDC and 0 to 6.5 VDC is likely for speed control. This is pure guessing on my part but unless you have a 310 VDC supply you are not going to run the motor. :(

This would go much better with a good schematic of the motor as used in a circuit (application). I am also guessing the controller is internal to the motor.

Ron
 

ronsimpson

Joined Oct 7, 2019
3,045
The 15V powers the smarts in the motor.
From this picture it looks like the 0-5.5V controls the speed.
link
There is a 3:1 price difference depending on where you look.
1705980897076.png
 

ElectricSpidey

Joined Dec 2, 2017
2,785
You have what is likely an air conditioner fan motor. The motor requires several voltages and signals to run starting with a 310 VDC power supply capable of 60 mA or 13 watts. The 15 VDC and 0 to 6.5 VDC is likely for speed control. This is pure guessing on my part but unless you have a 310 VDC supply you are not going to run the motor. :(

This would go much better with a good schematic of the motor as used in a circuit (application). I am also guessing the controller is internal to the motor.

Ron
The 310 volts DC is easy to come by.

220 volts AC, bridge rectifier and cap.

The 15 volts is also a piece of cake and the 0 to 6.5 can be easily derived from the 15.

The fan will run without the feedback from the blue wire but if you wanted the speed to be corrected to a fine control that would also be possible, but much more complicated.
 
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Reloadron

Joined Jan 15, 2015
7,523
The 310 volts DC is easy to come by.

220 volts AC, bridge rectifier and cap.

The 15 volts is also a piece of cake and the 0 to 6.5 can be easily derived from the 15.

The fan will run without the feedback from the blue wire but if you wanted the speed to be corrected to a fine control that would also be possible, but much more complicated.
That would work assuming one has the 220 volts to start with. I have no clue where the thread starter is located. North American mains has 220 ~ 240 VAC but would need a separate line run much like electric range or drier or other appliance requiring 240 VAC like a hot water heater. Nice part is minimal current required. :)

Ron
 

Thread Starter

lsheaf

Joined Jan 22, 2024
3
The 310 volts DC is easy to come by.

220 volts AC, bridge rectifier and cap.

The 15 volts is also a piece of cake and the 0 to 6.5 can be easily derived from the 15.

The fan will run without the feedback from the blue wire but if you wanted the speed to be corrected to a fine control that would also be possible, but much more complicated.
Thank you guys for all the responses. It is immensely helpful to me.
Instead of the bridge rectifier and cap - could I just get something like this (https://www.amazon.com/gp/product/B07N2FN18R/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1) ?

Then use a chopper to increase the voltage up to 310DC?
 

Reloadron

Joined Jan 15, 2015
7,523
You need the 300 volts DC which may take some doing but not much.
You need 15 VDC which is easy enough
You need 0 to 6.5 VAC which is not all that difficult.

On the 300 VDC since the current is low you can consider one of these as a cheap alternative. The other simple option is already mentioned using 220 or 240 VAC into a full wave bridge rectifier followed by a capacitor. The cap will charge to 1.414 times the RMS value so 220 VAC RMS * 1.414 = 311 VDC The 300 VDC is not all that critical. Another simple and inexpensive option can be found here. I believe this is what you were getting at with chopper.
The 6.5 VAC can be derived from an inexpensive filament transformer with a pot attached so you get 0 to 6.3 or 6.5 VAC.

I doubt the 15 VDC or 6.5 VAC draw any current to speak of.

Keep in mind these motors were primarily used to drive air conditioner blowers.

Ron
 

ElectricSpidey

Joined Dec 2, 2017
2,785
Ron there is no need for 0 to 6.5 VAC, it's 0 to 6.5 VDC.

0 to 6.5 VDC can be taken from the 15 VDC with a simple emitter follower circuit using 2 resistors a pot and one NPN transistor.

It's crude but should work.
 

Reloadron

Joined Jan 15, 2015
7,523
Ron there is no need for 0 to 6.5 VAC, it's 0 to 6.5 VDC.

0 to 6.5 VDC can be taken from the 15 VDC with a simple emitter follower circuit using 2 resistors a pot and one NPN transistor.

It's crude but should work.
Damn, I saw the 6.5 volts and for reasons unknown to me decided it was 0 to 6.5 VAC.

Heck from the 15 volt supply I would just use a cheap buck converter but with that 0 may be a problem. :)

That not working then heck yes, just roll your own as ElectricSpidey suggested.

Ron
 

panic mode

Joined Oct 10, 2011
2,759
That would work assuming one has the 220 volts to start with. I have no clue where the thread starter is located. North American mains has 220 ~ 240 VAC but would need a separate line run much like electric range or drier or other appliance requiring 240 VAC like a hot water heater. Nice part is minimal current required. :)

Ron
He still refuses to reveal location. I guess he does not really want to be helped.

btw, for this one could also use transformer or a voltage doubler to get the needed DC voltage from a typical US outlet.
15VDC supplies are readily available and speed control can be derived from 15V
just use 5k potentiometer:
connect wiper to speed control input of the motor
connect one side of the pot to 0V
connect the other side of pot through 6.2k resistor to 15V.

1706194630675.png
 
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panic mode

Joined Oct 10, 2011
2,759
if choosing to use voltage doubler, pair of 1N4007 diodes and 47uF capacitors will do, just make sure caps polarity is correct and that they are rated for sufficiently high voltage (they will see close to 200VDC each). smaller caps can work too but the ripple will be larger. i would also add bleeder resistor across each cap just in case. if for some reason, speed control input draws more current, adding emitter follower as suggested before will do the trick.
 

Thread Starter

lsheaf

Joined Jan 22, 2024
3
He still refuses to reveal location. I guess he does not really want to be helped.

btw, for this one could also use transformer or a voltage doubler to get the needed DC voltage from a typical US outlet.
15VDC supplies are readily available and speed control can be derived from 15V
just use 5k potentiometer:
connect wiper to speed control input of the motor
connect one side of the pot to 0V
connect the other side of pot through 6.2k resistor to 15V.

View attachment 313532
I am located in North America. I updated my profile so everyone can see where I'm located for future posts. Thank you for bringing that to my attention.
I'm not exactly sure what a wiper is although I feel like I've heard of that before.
 
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