Increased drag after DD motor was close to burn
- Thread starter hias9
- Start date
Looks more like 'browned' than the 'extra well done' i expected.
Def a testament to your cooling method considering the extreme conditions.
I think a bigass QS motor is in your near future if you want to continue to push power like that.
Def a testament to your cooling method considering the extreme conditions.
I think a bigass QS motor is in your near future if you want to continue to push power like that.
A QS205 would have a negative impact on weight, weight balance and handling, so I am trying to avoid that. The bike with batteries weights only 80lbs. I will have these motors rewinded with high quality wire and with the stuff that failed below 150 degrees celsius replaced by parts that work up to a higher temperature.
The motors however worked fine if you keep temperature always below 120 degrees celsius.
Is there any explanation for the highly increased eddy losses?
Any way to check if laminations are still magnetically separated?
Does the Statorade maybe have to be replaced after a year?
The motors however worked fine if you keep temperature always below 120 degrees celsius.
Is there any explanation for the highly increased eddy losses?
Any way to check if laminations are still magnetically separated?
Does the Statorade maybe have to be replaced after a year?
I completely agree.
Probably the "lightest" motor you could go with would be one of those mxus 5kw or cromotors, if you can find one..
It sounds more expensive to rewind this motor than get a new one.
I'm not sure if the material between the laminations is conductive, but if it is, you could go through each lamination with a multimeter to see if the material burning has created both an electrical short at least.
I believe statorade is not a permanent fill and degrades over time; see what ebikes.ca has to say.
Probably the "lightest" motor you could go with would be one of those mxus 5kw or cromotors, if you can find one..
It sounds more expensive to rewind this motor than get a new one.
I'm not sure if the material between the laminations is conductive, but if it is, you could go through each lamination with a multimeter to see if the material burning has created both an electrical short at least.
I believe statorade is not a permanent fill and degrades over time; see what ebikes.ca has to say.
A-DamW
100 W
Burning the enamel between the laminations might increase eddy current losses?
Yes, this would increase the eddy losses by a lot. But how can I measure if the enamel between the lamination has burned?
I would have expected the enamel not to burn before reaching much higher temperatures.
The laminations are electrically connected to each other (also on the new stator).
I would have expected the enamel not to burn before reaching much higher temperatures.
The laminations are electrically connected to each other (also on the new stator).
mxlemming
100 kW
- Joined
- Jul 17, 2020
- Messages
- 1,122
Quite possibly you've shorted some of the windings but not all together, which means there are mismatched phase windings (an unbalanced motor if you will...)
If the motor is unbalanced, it will have heavy losses as the "Eddie" currents won't be in the steel but around the windings.
I'd be surprised if you got it hot enough to make the laminations be ineffective, that would take huge amounts of heat is have thought.
You could test this by rewinding it. Wouldn't need to to do a full pack of copper, just put in one strand for the full amount of windings... It'll behave the same but with higher resistance.
I think this is normally how motors die. You can see this in the small concentrated areas of burn where the rest of the motor is relatively un charred. You can see in your pics that most of the windings are ok, where some have got so hot they've fused and cremated the insulation.
When I wound transformers at uni, the professor had us put layers of some special insulating tape between the coil layers even though the wire insulation could easily take the voltage. I think this means that small shorts between adjacent wires have a relatively small effect. I've seen a few but far from all transformers use this method.
If the motor is unbalanced, it will have heavy losses as the "Eddie" currents won't be in the steel but around the windings.
I'd be surprised if you got it hot enough to make the laminations be ineffective, that would take huge amounts of heat is have thought.
You could test this by rewinding it. Wouldn't need to to do a full pack of copper, just put in one strand for the full amount of windings... It'll behave the same but with higher resistance.
I think this is normally how motors die. You can see this in the small concentrated areas of burn where the rest of the motor is relatively un charred. You can see in your pics that most of the windings are ok, where some have got so hot they've fused and cremated the insulation.
When I wound transformers at uni, the professor had us put layers of some special insulating tape between the coil layers even though the wire insulation could easily take the voltage. I think this means that small shorts between adjacent wires have a relatively small effect. I've seen a few but far from all transformers use this method.
That is very likely what happened.
But the strange thing is that according to the milliohmmeter there is no short in the windings.
One strand (it has 21 strands in parallel) was cut by the heat when the ropes that keep the windings in place burned.
So resistance is not exactly equal over the 3 combinations, but close to equal.
But the strange thing is that according to the milliohmmeter there is no short in the windings.
One strand (it has 21 strands in parallel) was cut by the heat when the ropes that keep the windings in place burned.
So resistance is not exactly equal over the 3 combinations, but close to equal.
