Testing Continuity before DP25 connector attachment



We are new to this forum, we(my students and I) are assembling the OpenRov 2.6 kit and are continuity testing the motor wires before the DP25 connector is soldered to the wire leads.

At this point we cannot get any continuity in the motor wires? The wires were soldered to the motors

, shrink wrapped and glued as per the instructions, a tedious process.

Did we miss something? Did the ends of the copper coil wires have to sanded before soldering? Or would the heat of soldering strip that coating?




Hello Tom,

I am a little confused on the two points where you are touching the probes to the motor and wires. Once the wires are soldered, glued, and heat shrunk then there is no exposed electrical component on the motor side (that is the reason for the glue and heat shrink). If there were exposed electrical components then this can cause the motor to short in water.

Can you provide more details on the test that you are performing.

-Brian G.



Thanks for the reply, we are testing from one end of the copper wire that will be placed in the DP25 connector, should have shown that, and the wires on the motor coil that are exposed in the picture entering the mass of hot glue and blue shrink tubing.

I know that the copper coil wires are coated, should they be sanded before soldering?


Hello Tom,

Did you replace the motors? What is the desired result you are trying to achieve by performing this test?

Once you de-solder the colored wires that come attached to the motors the ends are already exposed and the new white wires can be soldered to the end of the motor coils

Once the glue and heat-shrink is applied there is no place on the motor for an electrical connection to be made, other than at the ends of the 1 meter long wires which will be connected to the DB-25 connector.

-Brian G.


Hi Tom:

When you go to attach the extension wires onto the motor, there is already a small length of motor wire that has the enamel stripped off of it. You should not need to do any more sanding or stripping of the enamel motor wire, in fact you should avoid doing so since you don't want to have any bare copper exposed to the water.

After you are done attaching the three wires to the motor, you can test for continuity by measuring the resistance between any two of the three wires (A,B, or C) that connect to the DB-25 connector. I think there should be something like 2 ohms of resistance between any two of the wires.



Thanks Walt.



Thanks your help Brian, I figured it out.