# 4 Motors Circuit Puzzle

#### djsfantasi

Joined Apr 11, 2010
7,772
Not yet, they´ve given us an extension until this wednesday. Would my last reply work?
In line for RotR

No.

#### jfran99

Joined Apr 21, 2021
30
I don´t understand why it wouldn´t work, as per my explanation I didn´t find any flaw. If you could please elaborate on your reply @djfantasi I would appreciate it.

#### jfran99

Joined Apr 21, 2021
30
How do you operate each motor individually? Your power feed is from the left switch, the right has no role.

Suppose the Motor connection has a switch that offers 4 options as i hinted at ny earlier post?
You would operate each motor individually in the first two positions of the first switch and then moving the second switch to the connection of the desired motor

#### Ramussons

Joined May 3, 2013
1,032
You would operate each motor individually in the first two positions of the first switch and then moving the second switch to the connection of the desired motor
There is no way you can run all those 4 motors independently at the same time, the way a solution is being attempted.

Or, maybe, I don't know If I understood your first question.

#### jfran99

Joined Apr 21, 2021
30
I think I know what you mean @Ramussons. You are correct, you wouldn´t be able to run two or more motors simultaneously in different directions. Nevertheless, this is not really something I would need (I want one at a time or all at the same time), so both of the following schematics would work right?

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#### djsfantasi

Joined Apr 11, 2010
7,772
On image 4062, do you see that whatever you do to one motor, is done to all?

#### jfran99

Joined Apr 21, 2021
30
On image 4062, do you see that whatever you do to one motor, is done to all?
Ahh okay yes now I see it. The part when the wire separates into 4 would allow the current to flow to the other motors.

#### jfran99

Joined Apr 21, 2021
30
When you mentioned putting the dp4t on the left, did you refer to something like this? This would allow every motor to be selected individually, and put on forward and reverse, but not simultaneously. What do you suggest?

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#### djsfantasi

Joined Apr 11, 2010
7,772
When you mentioned putting the dp4t on the left, did you refer to something like this? This would allow every motor to be selected individually, and put on forward and reverse, but not simultaneously. What do you suggest?
I’m in an airport security line.

But that is much closer to a correct solution. Much closer!

#### jfran99

Joined Apr 21, 2021
30
I’m in an airport security line.

But that is much closer to a correct solution. Much closer!

I´m trying to include the four tasks you mentioned, but it wouldn´t really work for individual powering with so many connections as the current would flow through one of the wires its not supposed to and power the other motor

#### djsfantasi

Joined Apr 11, 2010
7,772
I´m trying to include the four tasks you mentioned, but it wouldn´t really work for individual powering with so many connections as the current would flow through one of the wires its not supposed to and power the other motor

View attachment 237447
Think of what it has to do. Wire one function at a time.

Then, add sending power to the four individual switches.

Finally add controlling all motors in forward and reverse ...

At the airport bar

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#### Ramussons

Joined May 3, 2013
1,032
I was thinking on these lines.
Total control for each motor - 2P4T x 4 switches
Master switch 2P3T

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#### jfran99

Joined Apr 21, 2021
30
I think I might have gotten the answer! This should work right? With only 5 switches

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#### djsfantasi

Joined Apr 11, 2010
7,772
I think I might have gotten the answer! This should work right? With only 5 switches
Congratulations!

I originally said you’d need five switches.

It certainly looks like the correct solution. I’m still unpacking from my vacation and doing laundry, so haven’t traced every option, but at first glance it looks like you’ve figured it out...

I’m a tiny bit OCD (a good trait for an engineer) so refrain from saying I’m 100% sure this is the correct answer . I’d have to trace out at least 27 cases... (768 cases exist in your solution).

IMHO, your way of drawing the schematics is a bit obscure. But you seem to have done the work and arrived at a correct answer. Good for you!

#### jfran99

Joined Apr 21, 2021
30
Thanks!! And thank you for your help @djsfantasi and @Ramussons.

Yeah @djsfantasi my schematic is a bit obscure indeed, how do you suggest I should wire it to make it more clear?

Also, on a different note, if I were to actually build something like this, would there be anything else I would have to consider? Like how the difference in current when in master mode vs individual mode would affect the torque of the motors? Or adding a fuse maybe?

Ps: I hope you had a great vacation!

#### jfran99

Joined Apr 21, 2021
30

#### djsfantasi

Joined Apr 11, 2010
7,772
Thanks!! And thank you for your help @djsfantasi and @Ramussons.

Yeah @djsfantasi my schematic is a bit obscure indeed, how do you suggest I should wire it to make it more clear?

Also, on a different note, if I were to actually build something like this, would there be anything else I would have to consider? Like how the difference in current when in master mode vs individual mode would affect the torque of the motors? Or adding a fuse maybe?
Hello! I had a great vacation.

With regard to your schematic, I’d draw junctions closer to one device or the next. Drawn out, with junctions made in the middle of the traces, makes it difficult to discern their function. The next paragraphs explain how this works.

I’d break the schematic into functional segments. You pretty much have done this. This problem breaks down into power, master control, individual motor control and outputs or the motors.

I’d also use bus lines for common connections. Right to left for power and common signals (wires common to various functional segments of the circuit) and vertical for connections common to components in a functional segment.

As far as your consideration of other attributes, it depends on the circuit. Typically, I double check that the requirements of each functional segment are met. Such as signal voltage/current/impedance matching. Then, consider each individual component and ensure that they are selected appropriate to their use. E.g., don’t use a 1/8W resistor in a circuit where it is presented with 1/2W.

This problem has none of these considerations. You are using all passive components (switches). Your only remaining consideration is if the power supply (batteries) can supply enough current for all four motors at the same time. And if the power can supply that current long enough for your purposes.

All of these concerns require knowledge of the information in datasheets. Again, this problem just requires having the power supply datasheet and the motors datasheet.

#### jfran99

Joined Apr 21, 2021
30
Okay, I´ll make the junctions closer to the devices and more spaced out. Not completely sure about how the bus lines work. Could you send a quick sketch as I can´t seem to find anything in google?

#### jfran99

Joined Apr 21, 2021
30
Also, for the part about the current of the motors, does that mean that if each motor draws 1A at 24V, I´m going to need a battery with a max capacity of at least 4A to power all of the 4 motors at the same time?