I’m new to ssr’s, never used one (yet) but was considering one for a project. I had some difficulty finding a clear answer to this question, although I’m sure it’s out there somewhere. I have a DC motor connected to a speed controller which ranges from 0-7 volts. I want to use an Arduino and an ssr to cut power to the motor on command regardless of whether the speed controller is providing a voltage to the motor at any given time. I know this will work but the issue is that the speed controller is bidirectional, it can turn the motor 0-7v in both directions. This is the ssr I want to use:
https://www.amazon.com/SMAKN®-Channel-Level-Solid-Modules/dp/B00NKVLXY8/ref=sr_1_fkmr0_2?s=aht&ie=UTF8&qid=1486991581&sr=8-2-fkmr0&keywords=SMAKN®+5v+1-channel+High+Level+Solid+State+Relay+Board
Will this work in my scenario, essentially in the same fashion that a mechanical relay would work?
Secondly, if, for example, I wanted to use PWM to drop the speed of the motor by, say %50 of what the speed controller is providing, I figure that would work fine with an ssr since they will switch fast enough?
That is an AC relay(datasheet). Won't work with DC.
in the same fashion that a mechanical relay would work?
A mechanical relay does not care about polarity, a DC SSR does. So you can't switch both positive and negative voltages with DC SSR.
Groundfungus is correct this is a triac/SCR device and will not turn off once triggered.
Either use an FET bridge circuit or a relay. Not sure here how you reverse the motor, do you take the +7V to -7V?
It's an electronic speed controller for an rc truck. The truck is variable speed and moves forward and reverse. There's a motor on each axle and I want to be able to disable the motor on the front axle at certain times. If possible I also wanted to be able have a mode where I can drop the power to the front axle by 50% (for unrelated traction control reaons) and figured pwm would make this easy with an ssr. I have an extra channel on the receiver so that's no problem, I will use hook a nano up to the third chanel.
and figured pwm would make this easy with an ssr.
You can figure all you want an SSR will not work with the DC motors you have.
One has to wonder why you aske a question if you are not going to read or believe the answers you get. If you get a wrong answer on this forum others pile in like a ton of bricks. All the answers you have got are the same SSRs will not work for DC motors.
This looking like an XY problem.
What is the signal that is fed to the ESCs? Standard servo signal from a receiver?
One has to wonder why you assume I didn't read or believe the responses to my original question.
Dead-Ard asked, "Not sure here how you reverse the motor, do you take the +7V to -7V?"
I was simply explaining what was controlling the motors and offering a description of what the project was in case anyone had anything valuable to offer.
I figured I'd get a response like this, should have known better. Sorry.
You could put the Arduino between the receiver and the ESCs. Reading RC receiver with Arduino. You would then have full control of both motors. Use the third channel as a mode control signal.
In your link is how I have it set up, except I didn't think to signal the ESC with the arduino. Good idea, I'm going to give it a try. Wouldn't need a relay at all if that works.
moses1592:
One has to wonder why you assume I didn't read or believe the responses to my original question.
Because you were told in reply #1 and #2 that a SSR would not work with your DC motor. Yet in reply #3 you are still figuring you can use an SSR with a DC motor. That looks exactly like ignoring advice to me. Why does it not to you?