500 excessive insulation Clarence

[Fastfreddie]

I’m in the middle of an xlpower 520 and I bought some x Supra 4mm bullet connectors for the motor to esc. The problem I’m looking at is the wires on the motor already have the insulation stripped way back and after fitting them into the bullet end I have a considerable amount of bare wire left. I read that it’s not a good idea to trim the motor wires so I was thinking about just covering the excess with Plasti dip and heat shrink. Anyone else run into this issue before and if so what did you do?

 

[Smoggie]

You can trim the wires providing you don't remove all of the solder 'tinned' end of the wire. As long as you leave enough of the tinned part to make the solder joint into the connector you are ok.

 

[Geena]

Never trim, shorten or cut the motor wires. Doing that shortens the windings and will damage your motor. Solder the bullets onto the motor and put heat shrink on them, to cover the exposed wires. But don`t cut them. The following is straight from The manual for my Kontronik Pyro motor, but it holds true for all of the other brands too.


"The motor cables are the motor windings
carried out. You must not shorten these
cables. The winding will be irreparably
damaged. Cutting motor cables will
terminate all warranty claims."

 

[Fastfreddie]

I Did not cut them everything I found said exactly what you did Geena

 

[Smoggie]

Never trim, shorten or cut the motor wires. Doing that shortens the windings and will damage your motor. Solder the bullets onto the motor and put heat shrink on them, to cover the exposed wires. But don`t cut them. The following is straight from The manual for my Kontronik Pyro motor, but it holds true for all of the other brands too.


"The motor cables are the motor windings
carried out. You must not shorten these
cables. The winding will be irreparably
damaged. Cutting motor cables will
terminate all warranty claims."

Geena, The reason they say that is because the winding wires have a lacquer coating that you cant solder to, and which is extremely difficult to remove**. So if you cut off the pre-solder tinned end of the wire you have a very big problem soldering the bullets back on, hence the 'irreparable damaged' comment.

However providing you only trim a few mm off the end retaining enough of the solder tinned part to allow a good solder joint it does no harm at all. Soldering problems aside, actually shortening the wires in itself is not a problem. In fact the shorter you can make the wires the better, as it reduces resistive losses (not that the difference is big enough to notice)

Having said all of this, for the little bit of exposed wire shown in the pics above I'd not bother trimming, I'd just put heatshrink over it, like you suggested.

**The only reliable way I've found of stripping the lacquer is (with single thick strand windings) by scraping it off with a scalpel or sanding off with sandpaper. For multi strand windings it is much harder, only way I've found is using boiling caustic soda and salt mixture, which strips the lacquer off instantly but is very dangerous.

 

[Geena]

Geena, The reason they say that is because the winding wires have a lacquer coating that you cant solder to, and which is extremely difficult to remove**. So if you cut off the pre-solder tinned end of the wire you have a very big problem soldering the bullets back on, hence the 'irreparable damaged' comment.

However providing you only trim a few mm off the end retaining enough of the solder tinned part to allow a good solder joint it does no harm at all. Soldering problems aside, actually shortening the wires in itself is not a problem. In fact the shorter you can make the wires the better, as it reduces resistive losses (not that the difference is big enough to notice)

Having said all of this, for the little bit of exposed wire shown in the pics above I'd not bother trimming, I'd just put heatshrink over it, like you suggested.

**The only reliable way I've found of stripping the lacquer is (with single thick strand windings) by scraping it off with a scalpel or sanding off with sandpaper. For multi strand windings it is much harder, only way I've found is using boiling caustic soda and salt mixture, which strips the lacquer off instantly but is very dangerous.

I have to disagree with you on that. The manual clearly states not to shorten the motor wires, because it will irreparably damage the windings in the motor. Georges tells his scorpion customers not to cut. Kontronik says never cut them. But I’m not the one paying for your equipment,so cut away.

 

[Rob Lancaster]

Wow! Very interesting thread. I'm just throwing in my measly 2 cents here.
From what I know about electric motors, shortening the leads won't do anything to the motor except a minor lowering of the resistance factor. However, if the enamel is damaged on two or more adjacent windings in the motors coils the coils short and the voltage drops and the amps climb. This scenario leads to thermo- runaway which leads to more of the coils burning and shorting and more amp draw and more heat and on and on...

In your case, I'd be extra careful and contact the manufacture and have them explain their (theory of operation)... Unless their counting on using the motor leads as a kind of extra heat sinks, I can't see any reason why shortening the leads will damage the motor. But like Geena says, the manufacture says its so, so I want to know exactly why they say its so... I don't like mysteries........................
Hey if you find out other wise from the manufacture, please let us all know,,,,; so we'll all know. Ok; good luck...

 

[RandyDSok]

I'm also in the "just use some heat shrink tubing" and be done with it camp. Primarily, it doesn't void your warranty if nothing else. Second to that, it is much easier than it is to try and clean off that lacquer coating. In fact, I will apply enough heat shrink on both sides of my connections that there is no connector showing that could lead to a short later on.

I don't believe that shorting the wires themselves is what the manufacturers are worrying about enough to make it void your warranty. I believe its the off chance that while you are fighting to clean off the lacquer coating ( and it is very tough to clean off ) to make a surface you can solder too... you risk damaging the very thin lacquer coating on the inner windings which could potentially lead to an internal short.

Heat shrink tip... If possible, try to use a piece that just barely fits over the largest portion ( diameter ) of the connection/connector, this helps it to be able to shrink down to the size of the wire better than using a diameter that is too large to shrink down that far. On most banana type connectors, I use a single piece for both sides that is long enough to cover everything along with just enough of the wire insulation. After I've shrunk it all down all of the way, I use a razer knife to cut it around at the join between the male and female connectors. If you are afraid you may not know where that join is at, measure it before you shrink it all down.

 

[Smoggie]

I have to disagree with you on that. The manual clearly states not to shorten the motor wires, because it will irreparably damage the windings in the motor. Georges tells his scorpion customers not to cut. Kontronik says never cut them. But I’m not the one paying for your equipment,so cut away.

I don't think we really disagree. I also generally tell people not to cut the wires, but there are circumstances where a 'slight trim' is acceptable, as long as the solder termination is retained, as I tried to explain. For sure though, if there is any doubt or you aren't 100% confident, do not cut or trim.

FWIW I'm sure that if you ask George why he gives the 'do not cut' advice, you will find it's for the exact reasons I mentioned (difficulty in removal of the lacquer).