Powering motors to battery

#1

Newbie here,

So I initially had the polarities reversed for the motors (positive wires attached to negative plate [-] and negative wires attached to positive plate [+]) reasoning that it will only reverse the direction of the motors (similar to how it works with robot cars) because now the current is going the other way:

Also note that the battery was attached correctly, positive wire to positive [+] and negative wire to negative [-]. When I tried it smoke started coming out so I stopped it.

I then decided to put the polarities correctly for the motors. (positive wires attached to positive plate [+] and negative wires attached to negative plate [-]). When I put the power on there was no smoke. However, there was no current on the motor plates either. I took out a multimeter and tested that there was indeed a voltage for the battery on its positive [+] and negative [-] plates when the battery was attached. However when I did the same for the motor plates there was no voltage.

I then directly attached one motor to the battery plates and it successfully turned on (with the beep).

  1. Is the reversing of polarities issue the cause why I needed to do this?
  2. a. Is there a hidden circuit inside the frame connecting the battery and motor plates together?
    b. If a. is true, then is the circuit unusable somehow?
  3. Is it ok to attach all the motor plates to the battery plates (with matching polarity) via jumper wires or do I have to worry that the internal circuit (assuming there is one) had additional resistors?
#2

The frame plate is a simple conductor, unlike some PDBs that might include voltage regulators.
Reversing the wires might have messed up an esc. If so, you will need to replace it.

#3

Thank you for the quick reply! I was able to verify that each motor (with the esc) does work by connecting each one separately to the battery plates through jumper wires.
Should I connect the jumper wires in series (battery plates -> motor 1 plates -> motor 2 plates -> motor 3 plates -> motor 4 plates) or in parallel (battery plates -> motor 1 plates; battery plates -> motor 2 plates; battery plates -> motor 3 plates; battery plates -> motor 4 plates)?
I’m asking this because it appears the issue is that the conductor connecting the motor plates to the battery plates is not conducting, so I need to go around it with jumper wires.

#4

Are you building a drone? Drone motors are not DC motors they are AC motors. Although power is coming from a DC source (i.e., the battery) the electronics of the esc is sending AC power to the motors. Swapping any two wires of the wires from the esc to a motor will reverse the motors direction. I think jax200 is correct when he states that reversing the wires might have messed up an esc since they, like most electronic devices, require the correct polarity to avoid being damaged. Seeing the “magic smoke” in an electronic circuit is never a good thing. It usually means something has become fried due to excessive heat. Hope this helps.

#5

I am building this drone and thank you for clearing that up about the reversing. I didn’t realize it was switching from DC to AC. I also didn’t realize that in order to switch the direction you would have to do it between the esc and motor instead of the plates and the esc (I just viewed the esc as an extension of the motor which clearly was a very bad assumption).
However, could you (or someone else) explain whether I should connect the jumper wires in series or parallel? I already tested each motor (with each one connected to its esc) separately and had no problems getting each one to give the noise, but I don’t know how the components should be arranged when they are all connected together.

#6

What instructions are you using to build the drone? I ask because I don’t know what you are referring to when you mention jumper wires with respect to the esc and motors. In the drone that I built, the battery and the esc are connected to a power distribution plate without the need for “jumper wires”.

#7

We are both using the same drone, but after performing tests it appears the power distribution board is not working. So I need jumper wires to connect the motors (in which each one is connected to its own esc) to the battery. So should it be done in series or parallel?

#8

The motors need to be connected in parallel so that the same voltage is applied to each of the motors. If they were connected in series, each motor would not have the same applied voltage because of the voltage drop of the preceding motor in the circuit. BTW what test did you use to determine that the power distribution board is not working? I ask because the power distribution board is really simple (i.e., it is just some wiring) and I would not expect it to be defective - although I guess anything is possible.

#9

In the proceeding reply I said “so that the same voltage is applied to each of the motors”. I should have said “so that the same voltage is applied to each of the esc’s”. It is the esc that determines the voltage applied to the motor. Hope this didn’t cause any confusion.