Soild State relay can control the speed?

Mostly Printed CNC - MPCNC Advice
1

Hi Everybody,

I like to know CNC shield and GRBL can control speed rpm of my trimmer router by soild state relay?

Regard

Chris

2

A SSR can just switch on and off but not adjust the voltage. Therefore you’ll need a MosFET or something like that I think.

3

You usually use a triac to reduce the speed of a router. They actually only reduce the power of the motor, so you don’t get flat rpms. To control the rpms, you really need a pid speed controller.

4

This soild state relay has triac inside, it said 3-32v input. if I need add Potentiometer to adjust voltage from 0v to 3v control input for IR LED to let control triac in solid state relay, that will be work?

5

I don’t understand what you’re asking.

6

Sorry for my bad english,

I just ask, if good idea to connection varible resistor to solid state relay input to help control speed the motor?

I show you picture of oval drawing that where can I connect to solid state drive.

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7

No. That won’t work. That input is looking for any voltage over 3V. If it detects it, the output will be completely on.

8

So have you experience build AC motor control circuit?,

may you can give me an introduction to step for build circuit with Triac.

9

Building a motor controller for AC is quite different than for DC.
Unlike a DC motor, changing the voltage does not affect the speed.
Unlike a DC motor, changing the duty cycle with PWM does not control the speed predictably.
You need what is called a zero-crossing circuit. This is usually in the form of an optoisolator on a chip. Basically it triggers when the AC waveform crosses 0V, which signals to your circuit when the wave is starting. You can then choose (using a microcontroller, 555 timer, or whatever) how much of the waveform to send to the motor, and when to cut it off by triggering a TRIAC. This is called phase angle control. This is how AC light dimmers and fan speed controllers work.

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Here is a good video explaining the basics. This is not a circuit for beginners, because it uses mains power. https://www.youtube.com/watch?v=4N1uLth1o9o

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10

Thank you for explain clear about how triac work and different between AC and DC.

I decided brought new 2000watts AC motor speed controller which is triac included on circuit board that made by factory.

1 Like
11

it cost just $2.80

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Let us know how it works!