Speed control of 35 watt fan motor -(single phase AC induction)

Thread Starter

kuvz15

Joined Apr 17, 2017
13
Hey guys. Trying to put together a circuit to do the speed control of a single phase induction motor from a fan rated at 35 watts and runs at 220 / 240 V AC. The challenging part is that it needs to be done without the use of a micro controller. Basically there are 3 sub-systems namely: the switch-mode power supply, user-interface unit and the motor driver unit. I'm doing the motor driver unit which basically receives a 0 - 5V DC voltage signal from the user-interface unit and varies the speed of the motor according from 0 to its max speed. I'm inclined to using a triac and diac with possibly a zero-crossing IC (Optocoupler). I have come across a few circuits which make use of a triac/diac and potentiometer. I was thinking of implementing a circuit similar to these however, I will need to replace the pot with the reference voltage (in the range of 0 to 5v) from the user- interface unit. Any suggestions or circuit diagrams?
 

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Dodgydave

Joined Jun 22, 2012
9,313
There is a Temic chip U217b, that gets it's supply from the mains that can be used as a light dimmer/ heater controller, by applying a negative voltage on pin 4 from pin 7 ground, it has a built in zero crossing detection. Otherwise you will have to isolate it using an opto-coupler, and control the current in the led.



135-091abe1f3b.jpg

Datasheet..

https://www.google.co.uk/url?sa=t&source=web&rct=j&url=http://www.elektronik.sk/datasheet/U217B.pdf&ved=0ahUKEwjm8pWE-rfTAhUPPFAKHS0OBO4QFggaMAA&usg=AFQjCNHwiPh8P89ZyoV8VfIypX1sj0CyNw
 
Last edited:

MaxHeadRoom

Joined Jul 18, 2013
21,226
BTW, if using the circuit in AN-3006 and are using a micro in place of the 555, you do not need Q1 invertor transistor, just the 10k pull up.
Max.
 

Thread Starter

kuvz15

Joined Apr 17, 2017
13
BTW, if using the circuit in AN-3006 and are using a micro in place of the 555, you do not need Q1 invertor transistor, just the 10k pull up.
Max.
Okay that makes sense because Q1 is being used to trigger the 555 to create the pulse but if I omit the 555, what will then trigger the MOC3023 opto?
 

Thread Starter

kuvz15

Joined Apr 17, 2017
13
I understood you to mention in the OP that you intended using a micro?
If I'm mistaken then use the 555.
Max.
Yes, I mentioned that we are not allowed the use of micros. Thank you so much for suggesting the AN-3006 Max. Hopefully I will be able to implement the circuit correctly as this is my first electronic design project.
 

Dodgydave

Joined Jun 22, 2012
9,313
R1 is 10K, and will set the current in the Opto-coupler at around 10mA for 120Vac,,so if you use 230Vac it will be around 20mA.
 
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