Tetrix Thermal-Protected DC Motor Power Cable Modifications

[Teched3]

If you try to solder, you will likely melt the plastic and ruin the connectors to the motor brushes. You would be better off using a strain relief on the power cord (zip tie?).

[avanboekel]

Even if we could do this without melting anything, would it be legal? I think that we would be able to do it. We are just looking for it to be more reliable.

[Dale]

There's nothing that says you can't solder things on your minitbot. There's nothing that says you can't modify the motor cable. You do, indeed, need to be careful when soldering to the motor. Pre-tin both the motor pin and the wire with solder and then melt them together in the last step. A heatsink at the base of the motor pin would also be a good idea.

[dez250]

Even if it was legal, what advantage would you gain by doing this?

[avanboekel]

Originally Posted by dez250

Even if it was legal, what advantage would you gain by doing this?

It's more reliable. We know that the wires will not fall out of thier connectors. We had this problem a lot with prototyping and didn't want to risk anything when it comes time for competition.

[IndySam]

Originally Posted by avanboekel

It's more reliable. We know that the wires will not fall out of thier connectors. We had this problem a lot with prototyping and didn't want to risk anything when it comes time for competition.

If you are pulling the connector of the motor you would probably yank the wires of the motor if their soldered.

You need to provide strain relief for your wires. Try cable tying the wires to the motor body and you shouldn't have any reliability problems.

[dez250]

Originally Posted by avanboekel

It's more reliable. We know that the wires will not fall out of thier connectors. We had this problem a lot with prototyping and didn't want to risk anything when it comes time for competition.

Reliability is not a matter of if the product works how you want it to work, it is a matter of it is working as designed. In this case, I would believe the strain being applied to the cable is higher than it normally should be, thus disconnecting. If you give some strain relief to the connector by providing extra cable looped towards the motor and zip-tied, that should be a reliable fix for you.

Imagine though if you did solder the wire and the motor then failed, now not only do you have to replace the motor, but also the cable.

[tagayoff]

If you solder wires on the motor be forewarned that the plastic holding the terminals is extremely heat sensitive and melts rather easily. The temperature required for lead free solder makes the plastic turn to jello. With the resulting moving of the terminals. And if they move the connection to the internal brush tab will likely be broken. Then you will need to open the motor rendering it useless for competition.

[TheOtherGuy]

Originally Posted by dez250

Reliability is not a matter of if the product works how you want it to work, it is a matter of it is working as designed. In this case, I would believe the strain being applied to the cable is higher than it normally should be, thus disconnecting. If you give some strain relief to the connector by providing extra cable looped towards the motor and zip-tied, that should be a reliable fix for you.

Imagine though if you did solder the wire and the motor then failed, now not only do you have to replace the motor, but also the cable.

I did FTC in 2009 and noticed that even with a zip tie holding the wires onto the motor, the connectors are incredibly loose (they came that way) and tend to fall off. Pinching them a little smaller and using a strain relief would work though. Soldering works too (you can desolder of the motor fails). Just a matter of preference.