best sensor for fan monitoring

[jcaluma]

what do you think is the best sensor to be used for monitoring fans on
an equipment or system?......
as of now im choosing between hall-effect sensor and reflective sensor....
but i have a confusion on hall-effect sensors, i don't know if it will work on ac-supplied fans..................................need your inputs.....thanks

 

[Sebi]

If this fan a DC brushless type, it contains a bipolar hall sensor for commutation. With small work You can build into a third wire from hall sensor or transistor collector for monitoring.

 

[jcaluma]

what can you say about using reflective sensors instead?....

 

[Scubasteve]

Hey..

Sure, it is possible to use a white marker or a reflective strip on the fanblade and have a sensor come out and transmit and detect infrared light.. These are available ready made for you to use. It is the processing that will hurt you.

There are too many ways to do this, it is not worth going into it. I would recommend using a microcontroller, which would make the task a lot easier. What sort of readout do you want? LCD?

Steve

 

[jcaluma]

steve,

readout will just be an LED and a buzzer.

can you give me more recommendation on what to use on
this project.

thanks..


joy

 

[Scubasteve]

Hey there,

I myself do not have much experience in actual design, so I don't know the best ways to do things.. Is this for an industrial environment? I know there are integrated solutions on the market for this application.

I have a couple ideas, but I feel that you would find a better design already being marketed.

Let me know,

Steve

 

[Sebi]

If You need only LED and buzzer, apply a retriggerable monostable: when no (or slowly) coming pulses from reflective sensor, give a logical signal for alarm.

 

[jcaluma]

steve,

yeah this is to be applied for automated test equipment....this
tester is some kinda old that's why it has no such kind of thermal or
fan monitoring system..
maybe there is a ready made of this type, but i think it would be
better if i make my own design, you know just for a credit on my part..
actually one equipment here has already that kind of monitoring
system and i somehow copied it's principle.....that's using a hall-effect
sensor for the fan(DC fan) and a board controller(board was from the
manufacturer)...
but the problem on my project is the fan w/c is an AC supplied fan
compared to that of the other equipment w/c has a DC supplied fan...

another problem is the cost of a reflective sensor w/c is expensive...



sebi,

about the dc brushless fan you're asking, the fan is an AC supplied
fan....




please give me a strong recommendation on what to do....
thanks again!!!...

 

[jcaluma]

Sebi
Electronics Expert


Joined: 09 Jan 2003
Posts: 228

Posted: Mon Apr 14, 2003 6:44 am Post subject:

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If You need only LED and buzzer, apply a retriggerable monostable: when no (or slowly) coming pulses from reflective sensor, give a logical signal for alarm.



hi sebi,

about the thing you said above......what ic or device should i use for this?....
thanks again!....


joy