Interfacing tl494 pwm controller to arduino - Page 1
Forum section: electronics / beginners

author: husyn
author_rank: Newbie
timestamp: July 06, 2013, 09:39:02 pm
content: Hello Everyone,I'm trying to interface tl494 pwm controller to Arduino Uno but don't know exactly that which pin of tl494 should be connected to which pin of Arduino? Please help me out in this regard. Waiting for your Response.

author: madires
author_rank: Super Contributor
timestamp: July 06, 2013, 09:49:47 pm
content: Some more details about what you're trying to accomplish would be helpful.

author: cthree
author_rank: Frequent Contributor
timestamp: July 07, 2013, 03:00:33 am
content: Agreed. A little detail would be nice. You do know there is PWM capability built into the micro controller right? I'd be interested to know why you are using an additional external PWM controller. What is you application?

author: husyn
author_rank: Newbie
timestamp: July 07, 2013, 02:18:47 pm
content: Actually I have been assigned a duty by my Supervisor to control a dimmer that operates an electric fan so I am trying to interface an external PWM Controller tl494 to arduino uno and also a solid state relay.

author: c4757p
author_rank: Super Contributor
timestamp: July 07, 2013, 03:02:08 pm
content: Let me get this straight: You want to use an Arduino to control a TL494, which will output a PWM signal, and then that PWM signal will switch the SSR, which controls the fan?1) Arduino (AVR ATmega) can directly output PWM, there's no need for the TL494. TL494 is used in all-analog circuits like switching power supplies.2) SSRs aren't used for motor speed control. This would typically involve a TRIAC and some external control circuitry. (The SSR may very well contain a TRIAC, but it's not configured for the type of control you'd use for this.) You need to do some research on AC motor speed control circuits.

author: leb120
author_rank: Contributor
timestamp: July 07, 2013, 03:20:21 pm
content: Is the motor in the fan AC or DC?AC light dimming is usually accomplished by Phase control (a method of PWM for power limiting, applied to AC voltages).http://en.wikipedia.org/wiki/Phase_fired_controllersI know this is used for lighting, but not sure how different types of AC motors will behave, will probably make the fan noise unless you use filtering on the output.Bast AC motor speed control is VFDs, but this is probably overkill for small fans.https://en.wikipedia.org/wiki/Variable-frequency_driveHere is an existing thread about AC fanshttps://www.eevblog.com/forum/beginners/arduino-pwm-controlled-ac-motors/.DC light dimming is usually accomplished by Pulse-width modulation (PWM).http://en.wikipedia.org/wiki/Pulse_width_modulationThis is very common with LEDs and no filtering, they actually blink very quickly but thanks to Persistence of vision you eye sees it as a continuous glow.With or without filtering this is commonly used on DC fans, some brushless DC fans (computer fans) may not like unfiltered PWM, but some have four wires, one of which can be fed a PWM control signal.http://en.wikipedia.org/wiki/Brushless_DC_electric_motorin either case I don't see what a "tl494" does for you, if you do need PWM the Arduino can generate PWMs.http://www.ti.com/product/tl494

author: c4757p
author_rank: Super Contributor
timestamp: July 07, 2013, 03:28:54 pm
content: You can buy fan speed controllers...

author: free_electron
author_rank: Super Contributor
timestamp: July 07, 2013, 04:29:23 pm
content: Whoa. Now we're in to 3 phase fan control ?How many kilowatt is that fan ? 3 phase control is a bit more complicated....

author: husyn
author_rank: Newbie
timestamp: July 07, 2013, 04:51:16 pm
content: The ceiling fan is about 60-100 watts

author: c4757p
author_rank: Super Contributor
timestamp: July 07, 2013, 04:58:39 pm
content: Let me know if you find a three phase ceiling fan, I want to see it.Seriously, dude, not to be rude, but if you don't know the difference between a three-phase motor and a single-phase, you should not be anywhere near implementing your own speed control. Just buy one! Let's not be starting any fires or electrocuting ourselves.

author: leb120
author_rank: Contributor
timestamp: July 07, 2013, 05:50:04 pm
content: Maybe it's a3 speedceiling fan?If it is, this actually wouldn't be hard to switch between two different speeds, just replace the fan switch in the housing with a relay.You might be able to change to low speed during load shedding and switch back to normal selectable speeds the rest of the timeAlso, most wall dimmers and fan speed controllers are not just potentiometers, they use Phase control.They are going to be a little less efficient as slower speeds, but not nearly as bad as you are thinking, is isn't just a big resister in series.Most fans are going to be less efficient as slower speeds anyways even if you use the build in low on a fan's switch.