Need a way to switch motor polarity using relays

I have been searching FOREVER trying to find a suitable relay to control direction of a 12V, 6A DC motor using Arduino. I know I need a DPDT relay, but all that I can find are 12V or 24V for the load I need to switch. Does anyone have a recommendation?

thanks!

Please explain what your problem is. You can achieve direction reversal by either a DPDT relay or a pair of SPDT relays.

The problem is that all of the DPDT relays I have found are only rated for 1A load or require a 12/24V input voltage (which will not work using Arduino's 5V outputs). I am hoping someone has a relay that they may have used in the past that would meet these requirements.

Try a search at Digikey..com, can filter for whatever spec's you want. http://www.digikey.com/product-search/en/relays/power-relays-over-2-amps/1049447?k=relay

I have been searching FOREVER trying to find a suitable relay to control direction of a 12V, 6A DC motor using Arduino. I know I need a DPDT relay, but all that I can find are 12V or 24V for the load I need to switch. Does anyone have a recommendation?

Why not use an H-BRIDGE ?

You can get mosfets from Sparkfun that can easily switch 6A and you can use TC4427 mosfet switches.

Most relays require a relay driver circuit (a transistor or MOSFET, etc.). You can find relay driver boards with a relay and driver circuit built-in.

Note that a DPDT relay can control the direction, but you need another switch or relay to turn it off.

Or you can use an H-bridge motor driver, which works without relays. An H-driver can also be turned-off or used for PWM speed control.

Note that a DPDT relay can control the direction, but you need another switch or relay to turn it off.

Or you can use an H-bridge motor driver, which works without relays. An H-driver can also be turned-off or used for PWM speed control.

To be more specific. It's probably not a good idea reverse motor direction with a relay without turning off the power first. You can do it but the current surge might cause problems.

Relay h-bridge with SPST for enable, and DPDT for direction.

Didn't realize there were H-bridges with such high current capacity. I think that may be the best way to go. I didn't think about the negative effects associated with instantaneously reversing the direction. Thanks for all of the great input!

Didn't realize there were H-bridges with such high current capacity. I think that may be the best way to go. I didn't think about the negative effects associated with instantaneously reversing the direction. Thanks for all of the great input!

You do realize almost no one uses relays for H-bridges these days due to the advances in mosfet technology making very low on resistance high power mosfets relatively cheap. You do need a mosfet driver however. I use the TC4427 with 30A mosfets from Sparkfun.

You haven't mentioned speed control yet . I assume that means you only care about ON/OFF , correct ?

Correct... I have a carriage that moves up and down at a single speed.

You can use relays but it might be a good idea to add RC snubber circuits to prevent arcing.

Found this guy that looks like it has potential... https://www.pololu.com/product/2991

That should work.

cjswish:
Didn’t realize there were H-bridges with such high current capacity

Well had you considered there are bridges controlling electric motors in large bits of equipment? You want
5000V and 1000A, someone makes a bridge for it (typically 3-phase thyristor design though, not MOSFET H-bridge!)

Hi,

Found this guy that looks like it has potential... https://www.pololu.com/product/2991

Yes it will do the job, but read ALL the documentation on that page, it has no current limit facility, so make sure you put a fuse in the power line. What are you going to use as your power supply?

Tom... :)

Ask about current shunt modules for measuring motor current.

I'm using a 12V 10A SPS from Mean Well