Re: AC Fan motor speed control ideas
A phase-controller (dimmer) will always be noisy due to the sharp pulse, which makes the motor buzz. I use one in summer on my window fan.
You could use a variac, or transformer to cut back to say 160VAC, or put a series capacitor to the motor to slow it down. If you have any motor caps, try a 5uF or something.
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Re: AC Fan motor speed control ideas
I guess I could also try a regular transformer ? Not as cheap as the dimmers, but not as expensive and overkill as a full-sized variac either. Of course, I'd be stuck with the single fixed output voltage, so I'd have to find the sweet spot where the noise/speed are both acceptable. I think this was around 70v in my case.
I also found these things but I have no idea what they are and how it would be possible to hook one up with all those wires. I guess they're for a specific type of motor, since they mention a capacitor....Last edited by Dannyx; 06-17-2021, 12:25 PM.Leave a comment:
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Re: AC Fan motor speed control ideas
Yes these tiny boards all tend to be TRIAC phase control lamp dimmer circuits just like the wall mount.
If cheap is the only way to go, that's what you get with phase control. The buzzing is expected, you can stick a inductor in series to dampen out some of the buzzing. Probably have to hack the pot/series resistor for more reasonable values for your motor - system behavior depends on the motor, control device, and also the load... together...
There are specially made "motor" "dimmers" that you can get too... usually they're like "high" "medium" "low" "off" and not a continuous function in between.Leave a comment:
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Re: AC Fan motor speed control ideas
But it could also be a lamp in the case of the dimmer
Here: I drew the schematic for the ones I got off Aliexpress. They look about the same, save for the snubber (?) network on the left and the dual pot setup on the right (RV1 is a trimmer). I didn't bother to add values for the components too, so they're just as kicad spat them out....Attached FilesLast edited by Dannyx; 06-17-2021, 11:59 AM.Leave a comment:
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Re: AC Fan motor speed control ideas
I belive that is a "dimmer", is it not ?Leave a comment:
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AC Fan motor speed control ideas
Good day folks. What I'm trying to achieve may seem pretty simple and although I found lots of discussions on the topic, it's hard for me to settle on a definitive answer, so I thought I'd ask for more opinions.
I have a small inline duct fan which looks like this, which I want to slow down, the reason being overall noise. I have no idea what type of motor this is, because I can't exactly take it apart to inspect it without ruining it, but perhaps we can work it out by examining its behavior.
Two things I've tried: a variac and a cheap light dimmer (triac+diac inside of it). The variac worked great: as I lowered the voltage, the fan slowed down and didn't give off any immediate signs that I shouldn't be doing what I was doing.
The dimmer was less than ideal: other than the fact that the motor slowed down considerably as soon as I moved the slider a small fraction, which made the slider virtually useless, the motor buzzed quite noticeably and I was afraid to let it run like this for too long, fearing the triac might pop.
I also have one of these that I could try, but I reckon it's the same exact thing as the dimmer I just tried, since I see the same exact components, with the exception of the inductor. The light dimmer also has a large inductor, but other than that, they seem virtually identical: diac, triac, potentiometer, capacitor. I heard about different kinds of dimmers and stuff like "phase angle control", but wouldn't know how to measure and analyze any of this stuff without a scope, which I don't have. I think all garden-variety hardware store dimmers will be like this and wouldn't be much better...
Based on these observations, I believe we're dealing with a shaded pole motor ? The variac (transformer) solution seemed to work the best, but I'm definitely not going to dedicate a big variac to this one sole use, neither am I willing to invest in VFDs to drive a small motor, so I think I'll have to compromise.....
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Hi, I'm building a pottery wheel for my wife.
Since it needs to reverse direction and have a nice control over rpm, I decided to pick a diy electric scooter motor.
It operates at 48v and comes with a controller.
It has three wires for speed control
-5v
-gnd
-signal.
The problem is that if I use a 100k pot, motor starts spinning when 1.4v and will get to max revolutions at 3.4v. With this 2v range, the potentiometer is not really ideal, as it will change suddenly rpm with the slighlest touch.
I need something... -
I have a motor control board I am trying to repair. I've been told the motor is fine, but the control board will only make the motor go one direction but not the other. Power comes in through a linear transformer and then a rectifier bridge and then filter caps. No schematics for the board. Relays on the board are 24V so I started by setting my bench PSU to 24V and injecting voltage. There are several LEDs. All but one LED lights up. There are test points labelled +15V, 0V and -15V. When checking voltage potential between +15V and 0V, I get a perfect 15V. For -15V to 0V, my meter shows approximately... -
Hi,
i am asking for some Help.
I have one of these Nescafe Aeroccino (Milk Frother) things with a bad motor.
The Motor didn´t start anymore and internet is full of users just swapping the motor for a Mabuchi RF-500TB-12560.
So i got a few of these from Banggood.
I swapped the motor and now i have a new fault condition.
In a working Frother you would press the start button, it will light red and work for a few minutes.
If you press longer it will light blue and just mixup the milk.
With the new Motor it just starts... -
Patient is a Maytag/Whirlpool/Kenmore clothes dryer. Not sure of exact model, doesn't matter. All boards are out of production.
Specific problem is a Maytag 8544799 / WP8544799 motor-control board, aka Diehl Controls 708879-05. Customer states the board "doesn't work, motor doesn't run". Not sure how the repairman made that assessment, or if it's even accurate. He can't get replacement boards, and the owner decided to buy a new dryer, so whether this board is the problem is speculation on his part. Again, doesn't matter.
I've been over the board looking for... -
I was working on this machine yesterday and I now going to use an incandescent lights instead of a fuses to figure out what the issue is with it blowing control voltage rail but this not the only issue the coolant pump failed the meager test as well as the main motor as well this motor has 12 motor wire leads instead of the normal 9 wires
This metal lathe has a weird motor setup it has a soft start motor with a “Y” and a delta type of motor winding setup and it is not done in the motor pucker head enclosure it is with four different contactors wired in a configuration I have not...
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