replace melted phase wires - need advice

[oded]

the Golden Motor 108 1.5kw that I am using have very small diameter phase wires (16-18 gauge).
the motor is capable of up to 80 amps, and remains cool, but the phase wires melted after 10 minutes.

I'll try to replace them with thicker wires, but if opening the motor turns out to be too complicated, what will happen if I replace the phase wires coming out of the motor to thicker gauge wires, and leave the wires inside the motor as they are?
will they cause a bottle neck, or will there be an overall improvement?

 

[amberwolf]

If they are actually melting because of the size of the wire being too small, then they will be doing that along their entire length, including inside the motor and cable entry, so if you leave them alone they'll just continue to do this and then short together or to the metal they're next to, at some point.

Are the wires in a jacket, or individually in open air with airflow over them?

Also, if they are melting, it's possible that something is wrong with the system (controller too high phase current limit, false positive hall/phase combo, etc), or the usage is putting a higher actual load on the motor than it was designed for, causing phase currents to be higher than it's rated for, etc.

Since the motor doesnt' get hot, it's probably not a false positive, but the phase current could still be too high. This can be much higher than battery current, and difficult to test or monitor unless the controller has the hardware and can do this for you, which is not all that common in "ebike" stuff. If it can't measure it, it also probably has no way to set it or change it (though some controllers have a ratio setting, and you can then change that and/or the battery current to change the phase current).


If they are melting only near the connection between motor and controller, then the connection is poor and needs to be replaced with something low-resistance.

 

[oded]

Thanks.
the wires are bundled together in a jacket.
their width is extremely small for the current they suppose to deliver - I am guessing 16 gauge, so no wonder they melt.

they need to be replaced, no question. I am just wondering if replacing the outer portion of the wires only (I mean after they exit the motor case) is beneficial in some way, or if the inner part is left as it is, than there is no advantage in doing so.

 

[amberwolf]

I am just wondering if replacing the outer portion of the wires only (I mean after they exit the motor case) is beneficial in some way, or if the inner part is left as it is, than there is no advantage in doing so.

That is answered by the first part of my first reply, and the last part.

If they are actually melting because of the size of the wire being too small, then they will be doing that along their entire length, including inside the motor and cable entry, so if you leave them alone they'll just continue to do this and then short together or to the metal they're next to, at some point.

If they are melting only near the connection between motor and controller, then the connection is poor and needs to be replaced with something low-resistance.

Some other thread in the last few weeks had someone do calculations to see how much heat could be pulled out of the smaller wires inside the axle/motor by the thicker outside stuff, and it was negligible. (I think it's in an ebike11 thread?)

 

[oded]

OK. Thanks for the clarification

The wires are melting along their entire length. Connections are fine, and motor is cool.
So, they need to be replaced. Just hope it won't be too much of a problem, digging inside the motor.

Sent from my LM-G850 using Tapatalk

 

[amberwolf]

The wires are melting along their entire length. Connections are fine, and motor is cool.
So, they need to be replaced. Just hope it won't be too much of a problem, digging inside the motor.

Hopefully it will be easy enough to just unbolt the end cap the wires pass thru, and pull it off.

You may find it easier to unbolt that end, then *push* on the motor shaft at the output end, instead.
I recommend marking the cap and shell where they join so you can realign them the same at reinstall, just in case it matters.

 

[sungod1]

I forget where I heard it, maybe from GrinTech.... but somebody said the bafang style 9pin was rate for 30a and should not be pushed over that for too long. They said if you want to do more you should just use that other 3 pin water proof connector that I never remember the name off. I am no sure if that is just phase and sensor less or not.

 

[amberwolf]

I forget where I heard it, maybe from GrinTech.... but somebody said the bafang style 9pin was rate for 30a and should not be pushed over that for too long. They said if you want to do more you should just use that other 3 pin water proof connector that I never remember the name off. I am no sure if that is just phase and sensor less or not.

Are you sure you meant to post that in this thread? (if not, I can move it to where you intended it to go if you post a link).

It doesn't appear to have anything to do with this particular thread's problem of phase wires melting along their length because of being too small a gauge for the current. No specific connector has been mentioned, just wires and that "connectors are fine", so connector current limits don't apply.

 

[sungod1]

It kind of does. Those wire melted from a current overload and he said he had a 9pin .. I have a 9pin but I think those are the most common connection for a front or read hub motor right now. I knew not to dive the 9pin cable too much over 30a.. *shrug*

 

[oded]

I think it's a misunderstanding.
I don't use a 9 tooth connector. only the wires are warm. conccections are fine.

 

[amberwolf]

It kind of does. Those wire melted from a current overload and he said he had a 9pin .. I have a 9pin but I think those are the most common connection for a front or read hub motor right now. I knew not to dive the 9pin cable too much over 30a.. *shrug*

There's nothing in the thread referring to a 9-pin connector or cable (or stating the number of pins or wires at all, only the gauge of wire).

If you see something different, please link and quote it for me; it may mean there is a fault with the forum software that needs to be repaired.

It is also not a hubmotor; you can google the motor listed in the first post and find pictures of it.


FWIW, since the motor phase currents (the ones flowing thru the cable you refer to) aren't monitored by most ebike controllers (including the one in your bike in your thread), and are higher than the battery currents (just not continously), it is highly likely you have used a lot more than 30a in the phase wires of such a cable going to a hubmotor on an ebike, but simply had no way to know this was happening.