Hi all,
I need to set the speed of an industrial fan to either full speed (12amps), half speed or off. I also need to isolate the driving circuit from the ac. I thought an optocoupler (led to triac) should do it but I couldn't find anything that can handle the power in Digikey. Is there such a beast?
Thanks
Huh? Your trying to deliver the power through the optocoupler? I don't know much about this area but I would imagine you won't find any optocoupler that can do that. (all I've seen are < 1A)
I would think the standard method is to run the power directly through the triac and use the optocoupler on the gate of the triac. Ground the chasis of the device using the fan and you are pretty much set.
The gate current is significantly smaller than the drive current so you can use a normal optocoupler.
If you just need half power and not variable power then I'm sure you can just use a switch and some diodes. Not sure how well this would work with an ac motor though as it might cause some problems. (essentially either using direct AC or a half wave rectifier cutting the power used in half but unfortunately probably won't work with an AC motor or will probably atleast cause some problems)
I imagine what your trying to do is extremely typical and so if your having trouble finding the components then your probably going about it the wrong way.
Anyways, thats my 2c's. (Someone will correct me if I'm wrong. I'm sure Phil or Eyeore will call me a moron or some shit too...)
"Jon Slaughter"
** Exactly correct assessment.** You have got me & Graham all wrong - Jon.
Both of us really *love* you a whole lot !!!!!
But we are fearful that if we ever told you so
- it would go straight to your head.
...... Phil
Go to:
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.