24v Motor - Forward and Reverse

[MRK]

I think I know the answer to my question but thought I would post here to confirm. I would like to power a small 24v gear motor with forward and reverse direction. I purchased a Shelly Plus 2PM (black) because I thought it was what I needed. Unfortunately, the way that I have it wired, the "open" and "close" buttons in the Shelly app power the motor in the same direction. I was hoping the Shelly relay had some reverse polarity magic in there some where but it does not. It looks like I would need to wire in a separate relay with reversed polarity on either the 01 or 02 circuit, correct?

Here is how I have it wired now and yes, I understand that it is incorrect for what I'm trying to achieve.

[thgoebel]

On 27.11.2024 at 14:52, MRK said:

I understand that it is incorrect for what I'm trying to achieve.

It’s true. You need a commutator circuit:

 

Addendum:

Amended diagram below:

Edited Sunday at 10:00 AM by thgoebel

[wooly]

suggestion from thgoebel is in part correct, but apart that you would save a lot of money if you used a shelly UNI instead of a 2PM and buying two bare relays, without the control electronic, the connection to the relay in the drawin is not the best one: both NO contact must go to + and both NC to - .
This way with both realy in rest condition [deenergized] the motor would be at ground level, and move in one direction turning on one of the ralay.
With his connection the stop position is with one realy on and the other off, so always drawing current .

Edited November 27 by wooly

[thgoebel]

Unfortunately, the „other“ Shelly forum is down until November 29th. Thus I had to search in my circuit diagram archives and found the above circuit. In the said forum are a lot of commutator diagrams…

Found another diagram for Shelly UNI or UNi plus:

This diagram incorporates the necessary limit switches.

[wooly]

again pointing: the position with bot relays deenergized is the one in the last drawing, that is with grnd connected to the NC switch of both relay and +24 to the NO end of both relays.

[MRK]

Thanks everyone. 

[thgoebel]

Obviously, the diagram shown above is sometimes misleading. Wiring with this scheme

 

 

leads to motor action if both outputs of the Shelly are deactivated. Although this could be amended by setting the jumper for IN1 in „high“ position, it has a slightly higher power consumption because relay 1 is mostly activated.

Thus, use this diagram instead:

[wooly]

even better [cheaper]: use an UNI+ so you have also the spare input for ambiental sensors, including one analog sensor that you could use to connect a device that can read the position.

Edited Sunday at 12:13 PM by wooly

[thgoebel]

Some people may like the cover/roller user interface which is available with Shelly 2PM, but not with UNI. Safety reasons don’t play a role in this game cause the commutator scheme is inherently safe against simultaneous switching both relays.

[wooly]

but  in this way you cannot measure current, so you cannot do the calibration. using an UNI you may couple a potentiomenter on the porot output and read it on analog in, so you may has also the "go-to:"  function that on the 2P with interposed relays would not work.

[thgoebel]

With two power supplies and two SPDT relays a calibration with Shelly (plus) 2PM (Gen3) is even possible…

Edited Sunday at 01:45 PM by thgoebel

[wooly]

two power supply [because there is one also per the shelly ...) and two extra relay ?
Are you a transformer trader ?
If demand were so high shelly could sell a 2DC, that can be fed at 12 or 24V (relay at 5 V), doing current measurement on a shunt, and that for the rest would appear exactly as a a 2PM in cover mode, and would have the same features and interface [except the frequency one, and only the cover profile]

[thgoebel]

Obviously, you

(a) are absolutely right what the Shelly DC device concerns, and

(b) didn’t count the amount of required PS correctly.

To give you the chance for a better counting, I did replace the scheme above with a more comprehensible one.

[wooly]

the power supply actually in your configuration are three, since there i salso the one that fed the shelly, it is not "extra" so the additional ones are just two.

[thgoebel]

No extra power supply to feed the Shelly! Total amount of PS is two…

Sorry for misunderstanding: You’re counting the internal power supply of the Shelly too. Nice try to be right after all…

Sorry to say this: EOT

Edited Sunday at 02:11 PM by thgoebel