I have spent a few years trying to find a rotary switch like this. Always thinking it was a rotary decoder but is not. It turns endlessly but only performs a 5-step fan speed level. If you look close there is a tiny ball in the one picture that has a solid copper ring. When turning, the ball goes around and then hits a stop but the knob can continue to rotate. Until it turns the other direction the ball then goes 320 degrees the other way and hits the stop again. The first picture drops onto the second picture piece.
I suspect, but could be wrong, as the it rotates it increases or decreases in resistance. But putting a meter on it, the resistance steps and isn't linear. I have 4 switches like this that no longer work and appear to have a short across the outer pins which makes contact simultaneously to both outer polls at the same time.
This is the circuit of how it works. It rotates and creates a momentary circuit closure to the fan speed stepper to increase fan speed clockwise and decreases speed counter-clockwise.
I desperate to find a switch that can replicate this. Only other way to make a repair is to buy a whole used controller just to scavenge this switch.
Stu
When you turn it CW and CCW and you get both A and B turning on and off, it means that it must be rotary encoder.As mentioned above...I have already tried several encoder switches and non have worked. Possibly because the EC11 /EC12 /EN11 series isn't quite the same as Alps used with this one. The duration of the square wave maybe is the issue.
I bought EC12E1220813, EN11HNM1AF15. I had to buy ones that were similarly shaped and sized.
I am willing to buy another series for testing as these are cheap if someone can get me another encoder series.
If it is a pot that turns 360 degrees without a stop then at one point the speed of the fan will change from min to max, I can hardly see this acceptable feature.It looks to me like it may be a potentiometer with (20?) discrete steps.
ALPS is well known: www.alps.com/products/e/category_potentiometer.html
Have you tried measuring resistance between the two end terminals and from the centre terminal to the end terminals while the shaft is rotated? It looks to me like it may be a potentiometer with (20?) discrete steps. I don't see two switches. I see the inner ring of contacts being the wiper, the outer ring being resistance taps, and the ball being a bridge (single switch) between inner and outer contacts. If that's the case, then a standard pot might well work as a substitute. Worth a try.
It's a potentiometer (A custom one). Figure 7, here **broken link removed** would basically describe the operation and a possible way to engineer a replacement with a dual gang potentiometer. Of course, that likely won't fit in your space.
Volume controls have tapers because loudness isn't linear.
The two semicircular "bits" have a non-linear resistance from end to end.
Your assignment for now, it to:
1) Measure the end to end resistance of the semicircular bit
2) and the center to the pin. (put a probe on the end pin) and a probe on the center of the carbon track.
3) Look at the resistance from the center to the end of each carbon bit.
Do it in a way that we can follow.
In reality, you should be able to disassemble, clean and out it back together, but lets see what you have first.
There is a VERY SLIGHT possibility that you could replace this with an electronic potentiometer, encoder and a microprocessor to fit in the space. (the encoder would fit in the space). You must have the max current and voltage used for that to even be a possibility.
It's a potentiometer (A custom one). Figure 7, here **broken link removed** would basically describe the operation and a possible way to engineer a replacement with a dual gang potentiometer. Of course, that likely won't fit in your space.
Volume controls have tapers because loudness isn't linear.
The two semicircular "bits" have a non-linear resistance from end to end.
Your assignment for now, it to:
1) Measure the end to end resistance of the semicircular bit
2) and the center to the pin. (put a probe on the end pin) and a probe on the center of the carbon track.
3) Look at the resistance from the center to the end of each carbon bit.
Do it in a way that we can follow.
In reality, you should be able to disassemble, clean and out it back together, but lets see what you have first.
There is a VERY SLIGHT possibility that you could replace this with an electronic potentiometer, encoder and a microprocessor to fit in the space. (the encoder would fit in the space). You must have the max current and voltage used for that to even be a possibility.
Measure the naked elements. No slider. The left white annotation, to just before the green attachment post. Then halfway from the laft-white annotation. Do the same on the right side.
Just want to get an idea of the max resistance and the arrangement.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?