110AC motor driver using arduino.

Thread Starter

pjreijiri

Joined Aug 19, 2015
98
Hello everyone,
I am working on a project and don't know where to start. I worked with DC motors before but I haven't worked with AC motors, and I don't have much experience with 110VAC as well.

What I have is a motor with 2 sensors. The sensors are used as end of travel switches. I already figured that part out.
What I need help with is how to run the AC motor using an arduino. I am not sure which ICs to use and if there are recommendations to follow. I am still doing my research but thought of asking here as well in case I miss something.

The motor is 1.4A only.

Thanks in advance
 

MaxHeadRoom

Joined Jul 18, 2013
21,257
Use a Triac opto. (Fairchild AN-3006) and a zero crossing Triac (Not random phase)!.
If you need to drive the Opto from the Arduino, use a 2n7000, I have never used Arduino. Just Picmicro's.
Max.
 

Irving

Joined Jan 30, 2016
951
Recommendations? Unless you know what you're doing with 110vAC. don't!

But if you must, then:

#1 make sure you have a double-pole isolating switch on the AC feed to the motor and use it religiously; ideally feed this from a ground fault circuit interrupter (GFCI).
#2 make sure you have adequate separation between AC and low voltage (lv) stuff. Don't run AC and lv wires alongside each other.
#3 make sure your motor casing is grounded to the AC protective earth. Ideally, AC wiring should be in grounded conduit.
#4 make sure your limit switches are voltage free contacts and their wiring is kept well away from the AC wiring
#5 make sure your Arduino power supply is properly isolated.
#6 make sure your Triac and other AC switching components are securely mounted in a suitable protective box with adequate heatsinks/cooling if needed. (If you don't know how to assess this, ask). If the box is metal, make sure its grounded too.

Rather than use a Opto-Diac + Triac combo and associated components for the snubber network, etc., have a look at off-the-shelf Arduino-compatible AC solid state relay (SSR) boards of which there are many; it'll involve less AC wiring and is arguably a safer option. Suppliers like BangGood sell them, often cheaper than you can buy the parts for the alternative route.

I'm sure there'll be someone who'll say this is overkill but I'd rather the OP be safe than sorry...
 

btebo

Joined Jul 7, 2017
98
Use a Triac opto. (Fairchild AN-3006) and a zero crossing Triac (Not random phase)!.
If you need to drive the Opto from the Arduino, use a 2n7000, I have never used Arduino. Just Picmicro's.
Max.
Dear Max,

I thought one used zero crossing for things like incandescent bulbs - if the filament is cold, it has low resistance and it's better to turn on "slowly" than apply power all at once (blowing the bulb).

As for induction motors, I thought you would want more voltage/current to get it started. What have I forgotten (or misunderstood)?

Balad
 

MaxHeadRoom

Joined Jul 18, 2013
21,257
Essentially what I described in my first post IS a SSR circuit.
Total isolation from the AC supply.


I thought one used zero crossing for things like incandescent bulbs - if the filament is cold, it has low resistance and it's better to turn on "slowly" than apply power all at once (blowing the bulb).
As for induction motors, I thought you would want more voltage/current to get it started. What have I forgotten (or misunderstood)?
You have it backwards, the Zero crossing switches full on when ever the wave form crosses zero, it is designed for power loads, the advantage being that less inrush current and EMI emissions.
The triac that uses Phase control, allows switching at any point on each 180° half of the supply frequency for varying the energy, power tool RPM control etc.
The Fairchild AN-3006 explains it, as well as AN-3003, random phase control. Page.5 shows interfacing with micro's.
Max.
 

andrewmm

Joined Feb 25, 2011
535

MaxHeadRoom

Joined Jul 18, 2013
21,257
If you want to control speed, thats a little bit more involved. It also has the risk that speed control can easily make a lot of electrical noise that will smash local radio reception,
this could be a good place to start
https://create.arduino.cc/projecthub/saulius-bandzevicius/arduino-based-universal-ac-motor-speed-controller-a4ceaf
I wouldn't consider that a 'Starting point' it involves an encoder fitted to the motor in order for PID control to be used, For simple applications the Typical Triac phase angle control could be used with snubber for EMI elimination.
Max.
 

mcardoso

Joined May 19, 2020
141
Hello everyone,
I am working on a project and don't know where to start. I worked with DC motors before but I haven't worked with AC motors, and I don't have much experience with 110VAC as well.

What I have is a motor with 2 sensors. The sensors are used as end of travel switches. I already figured that part out.
What I need help with is how to run the AC motor using an arduino. I am not sure which ICs to use and if there are recommendations to follow. I am still doing my research but thought of asking here as well in case I miss something.

The motor is 1.4A only.

Thanks in advance
Hi!

A simple way to connect an AC load to a micro is a mechanical or solid state relay:

For example: https://www.digikey.com/product-detail/en/sensata-crydom/D1225-10/CC2113-ND/751963 (This one is not good for your application, but an example)

They are dirt simple to control and offer a great interface between low control voltages and large AC loads. You can get them in zero-crossing flavors if your need require it (I don't see why you do for an AC motor). I would recommend the solid state, but a mechanical relay offers air gap isolation from the AC load if you can drive the coil current requirement with your circuit.

From the controls perspective, I question why you are using a single phase AC motor for what sounds like position control. These motors have a large mechanical inertia that will cause the motor to spin down slowly when power is removed. This might be perfect for your application, but wanted to bring it to your attention.

Industry uses 3-phase AC induction motors using Variable Frequency Drives (VFDs). These offer both velocity and positional control with good torque across the entire speed range of the motor. VFDs have gotten very inexpensive lately:

https://www.automationdirect.com/adc/shopping/catalog/drives_-a-_soft_starters/ac_variable_frequency_drives_(vfd)/micro/gs1-10p2
 

MaxHeadRoom

Joined Jul 18, 2013
21,257
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