next topic »

[on:]

Hello,

first of all please let me excuse myself for my lack of knowledge in electronics; I've never built a circuit before therefore my question might be very trivial.

What i want to achieve is to control a tube-motor(bidirectional) by the arduino(seeduino in particular). I now have a switch on the power cord (230V) going to the motor which when rests in the middle does nothing; when I turn it left, the motor turns left; when i turn it right, the motor turns right. I'd like to replace this switch with an arduino controlled switch. herefore I've bought a seeduino with a micro-usb port and an extra 4 relay module.

If i now disassemble the original switch I see what it does is only switching between the wires - ground is connected to the motor directly, then one of the wires seems also to go directly to the motor, the other wire is either routed to point 3 or point 4 of motor's inputs- this seems to let the motor run/spin in one of it's directions.

attempting to replace this with a arduino+relay module led me to draw a simple schema, please could you look if what I want to achieve can be connected like this? I don't know how to connect the arduino to the module yet but that should be standard I assume(like connect seeduino (digital) output 1 to input1 on the relay module, same with output 2, while keeping the GND and VOC also connected), my concerns are more about the high-circuit..
I know I'm missing a lot here, therefore please your comments..
thank you

[Reply #1 on:]

I have no idea what a "tube motor" is so I'm assuming that you understand the pinout there and have the power connections right.

Looking at how you have your relays wired, you have the potential to create a short circuit if both relays are energized. That's not a good idea unless you're the type of person that never writes software bugs and never has a hardware failure.

The + from your main power should go to the common of the first relay, the NO output of that first relay to the common of the second relay, and then the NC and NO of that second relay should go to 3 and 4 of the motor. This way the first relay controls power on/off and the second relay controls direction.

Terry's wiki on relay boards does a great job explaining how to hook these things up.

[Reply #2 on:]

Thank you Chagrin; I've re-drawn the schema based on your suggestion. so this way there less room for a possible short circuit?

the  tube motor(don't know if that's the correct name for it)  should now be wired correctly, so I'll keep that - i only could find the now attached, if you can have a look..)

I'd also like to double check If I'm using the correct relay module for this purpose - it's this one: http://www.sainsonic.com/zen/albums/ebay/nichegeek/20-018-101/IMG_0058.JPG

[Reply #3 on:]

Yes, your relay wiring is as I described. I'm still not clear on those four motor wires though so I'm leaving that to your discretion; I'm assuming that it's some type of AC motor and I'm not knowledgeable enough in AC motors to offer advice that could blow up someone else's stuff

Your relay module should be fine for this task. The critical thing to look out for is the amperage of the relays (which, as an aside, don't care if it's AC or DC current so long as you stay under the limits printed on the relay). Your board shows 10A relays and that should be more than plenty for a motor lifting this light of a load. Also be aware that your relay board is capable of optical isolation -- without a jumper between the JD-VCC pin and VCC pin it's expected that you have a second 5V power supply providing power to JD-VCC and GND and the Arduino's GND pin is not connected. Again, the link to the wiki I posted above explains this.

[Reply #4 on:]

thank you; this is very useful information for me. I'm going thru the link you've provided now.