Hi Everyone,

New member here—joined today!

I've built a 2-stop dumbwaiter running from basement kitchen to ground level kitchen. Thought the logic controller would be simple, so I used AI for help. Got 2 circuit diagrams based on 2x 12V 30A DPDT relays—I've got all the hardware ready, but the diagrams totally confuse me.

Can someone please:

1. Explain how these circuits work (or what's wrong with them)?
2. Or better yet—provide a clearer, simpler alternative?

Attachments:

Thanks in advance!
Best regards,
Ajeet

 

Hi Everyone,

New member here—joined today!

I've built a 2-stop dumbwaiter running from basement kitchen to ground level kitchen. Thought the logic controller would be simple, so I used AI for help. Got 2 circuit diagrams based on 2x 12V 30A DPDT relays—I've got all the hardware ready, but the diagrams totally confuse me.

Can someone please:

1. Explain how these circuits work (or what's wrong with them)?
2. Or better yet—provide a clearer, simpler alternative?

Attachments:

Thanks in advance!
Best regards,
Ajeet

The posted circuit images cutoff important parts of the circuit. Post complete circuit diagrams.

 

 

Welcome to AAC

Wow, they are confusing....

It's not that complicated - basically two circuits - one to call/send the lift up, as long as its already down, and one to call/send it down, as long as its already up.

It's not clear if you required a call and a send option on each floor - ie the same push button calls the lift if its not there and sends it if it is there. Alternatively, and simpler, the PB just calls the lift, assuming its waiting at the other end, there is no send function.

What motor do you have?

 

Welcome to AAC

Wow, they are confusing....

It's not that complicated - basically two circuits - one to call/send the lift up, as long as its already down, and one to call/send it down, as long as its already up.

It's not clear if you required a call and a send option on each floor - ie the same push button calls the lift if its not there and sends it if it is there. Alternatively, and simpler, the PB just calls the lift, assuming its waiting at the other end, there is no send function.

What motor do you have?

I’m having trouble understanding the contacts on the relay—specifically, which contact corresponds to which spade terminal. The labeling isn’t very clear to me, and I’m unsure how to correctly identify the connections.


Could someone please explain how the relay contacts map to the spade terminals, or point me to a diagram that makes this easier to understand?

 

Welcome to AAC

Wow, they are confusing....

It's not that complicated - basically two circuits - one to call/send the lift up, as long as its already down, and one to call/send it down, as long as its already up.

It's not clear if you required a call and a send option on each floor - ie the same push button calls the lift if its not there and sends it if it is there. Alternatively, and simpler, the PB just calls the lift, assuming its waiting at the other end, there is no send function.

What motor do you have?

The same pushbutton will be used both to send the car and to call it back.


The motor is a 220V Chinese geared electric hoist, rated to lift up to 500 kg.

 

I’m having trouble understanding the contacts on the relay—specifically, which contact corresponds to which spade terminal. The labeling isn’t very clear to me, and I’m unsure how to correctly identify the connections.


Could someone please explain how the relay contacts map to the spade terminals, or point me to a diagram that makes this easier to understand?

I'm not sure I could safely say from those diagrams. Does your AC motor have forward and reverse terminals or just field and armature windings?

 

I'm not sure I could safely say from those diagrams. Does your AC motor have forward and reverse terminals or just field and armature windings?

It has forward and reverse terminals.

 

The same pushbutton will be used both to send the car and to call it

Meaning one button at each kitchen that sends or receives depending on the location of the waiter?

 

Meaning one button at each kitchen that sends or receives depending on the location of the waiter?

Yes !!!

 

It has forward and reverse terminals.

Sorry, I should have asked as well - Just 3 wires, red, white, black or 4 wires (colours)?

 

Sorry, I should have asked as well - Just 3 wires, red, white, black or 4 wires (colours)?

Just 3 wires, red, white and black

 

View attachment 365218View attachment 365217

The upper diagram is chopped off at the left. What is at the left of the diagram?

 

Suggestion 1, without including any limit switches.
Sw1 and Sw2 are SPDT momentary switches with a center OFF position.
Press and hold switch to activate as needed.

 

Suggestion 1, without including any limit switches.
Sw1 and Sw2 are SPDT momentary switches with a center OFF position.
Press and hold switch to activate as needed.

That doesn't meet the TS requirements - a single button at each location calls the lift if it's at the remote location or sends it if it's already local.

I'm struggling to understand the AI generated solutions - I'm not convinced either are complete or correct.

 

I believe it does.
Either switch can lower or raise the lift.

 

After many hours of tinkering with the circuit, countless trial‑and‑error attempts, and repeatedly asking questions from Gemini AI, I’ve finally arrived at the design shown above. This is the version I’ll be finalizing and working with on Monday. I really hope it works!

I think I would be using another pair of SPST relays for the 240V motor connections.

 

OK, what does the line from R_UP NC to the R-DOWN switch represent? And where are the motor connections? I'm not sure this will work... For a start there is no power to either relay coil, the 12v only connects to the left-hand NC of R_UP and never to the lower relay. What activates the INTERLOCK switches?

 

OK, what does the line from R_UP NC to the R-DOWN switch represent? And where are the motor connections? I'm not sure this will work...

It is a jumper connection to a virtual interlock (As told by Gemini AI). Motor connections i would worry about later once the latching and interlocking logic is successful.

 

It is a jumper connection to a virtual interlock (As told by Gemini AI). Motor connections i would worry about later once the latching and interlocking logic is successful.

What is that? You realise there is no connection from 12v to either relay coil so nothing will happen...