Is it possible to measure what a motor is capable of?
- Thread starter tdneVmoDK
- Start date
Alan B
100 GW
make a dyno.
http://en.wikipedia.org/wiki/Dynamometer
http://en.wikipedia.org/wiki/Dynamometer
neptronix said:If you can find a place that can do a motorcycle dyno.. you can probably convince them to do a dyno run for you
If i put on a 300 volt battery, 300 volt 1000 amp controller, it would kill a motor that is only capable og 60 volts. So how do i find out what the motor i rated to? There a no markings og signs on the motor. It is a hub motor form an erider.
There is no way to know what the factory 'rated' the motor, if you don't know what motor it is.
Most people on here run stuff well beyond its limits. It's not like its indestructible at the rated power, but blows up 20% above it. It all depends on how its used. I'm running 6-8X more power into my hub than it was rated for.
The size and type of motor will give you a good idea of its capabilities. 1000W motors are fairly big, 500W are small, and 250/350W motors are often tiny. Geared 500W hubs generally can't take much more than the ratings, whereas DD 500W hubs can often take 2KW fairly well. Again, go up a very big hill at low speeds, and most any motor will melt. Look around at other motors ratings to give you an idea of what yours might be.
If you have access to a dyno, increasing the power until the efficiency starts to drop off will give you a good idea of the upper limits. If it puts out 1,800W with 2kW in, and only 1,900W with 3kW in, you know to not run it past 2kW. Below that 'reasonable' limit, its just a game of how you want to use it. If you can understand its thermal limits, you can manage it at the upper limits. If you don't want to care about the motors temp, you might want to back it down dramatically. As long as the motor is cool, it should be happy.
Most people on here run stuff well beyond its limits. It's not like its indestructible at the rated power, but blows up 20% above it. It all depends on how its used. I'm running 6-8X more power into my hub than it was rated for.
The size and type of motor will give you a good idea of its capabilities. 1000W motors are fairly big, 500W are small, and 250/350W motors are often tiny. Geared 500W hubs generally can't take much more than the ratings, whereas DD 500W hubs can often take 2KW fairly well. Again, go up a very big hill at low speeds, and most any motor will melt. Look around at other motors ratings to give you an idea of what yours might be.
If you have access to a dyno, increasing the power until the efficiency starts to drop off will give you a good idea of the upper limits. If it puts out 1,800W with 2kW in, and only 1,900W with 3kW in, you know to not run it past 2kW. Below that 'reasonable' limit, its just a game of how you want to use it. If you can understand its thermal limits, you can manage it at the upper limits. If you don't want to care about the motors temp, you might want to back it down dramatically. As long as the motor is cool, it should be happy.
tdneVmoDK said:neptronix said:If you can find a place that can do a motorcycle dyno.. you can probably convince them to do a dyno run for you
If i put on a 300 volt battery, 300 volt 1000 amp controller, it would kill a motor that is only capable og 60 volts. So how do i find out what the motor i rated to? There a no markings og signs on the motor. It is a hub motor form an erider.
Most hub motors max out at a few thousand watts. Some will take about 5kW-10kW for short periods of time without blowing.
The best way to find out what an unknown motor can take is to gradually bump up the amps and volts, ride it, hit some hills etc.. starting from 36v/15a.. and see how the heat is..
Warm to the touch = just right
Hot to the touch = you're overdoing it.
Too hot to touch = verging on a total meltdown, or has already.
ZOMGVTEK said:
Oh! i did not know that.
So i could actually just put a programmable controller onto it, and a clamp amp meter on the battery + And when i feel that the acceleration begins to flatten out, even though i'm twisting the throttle, i know where the max output is? Is it because it cannot exceed it's RPM limit? If so, i could put on larger tyres
rhitee05
10 kW
There are really two different limits here. A continuous rating is based on the thermal limits, i.e. how much heat will start to melt insulation and cause permanent damage. This sets how much power a motor can put out over a long period of time, but higher power is possible in shorter bursts.
There's also a limit to how much torque the motor can put out, which is based on the magnetic properties of the motor. This is the point where you'll get 1.8 kW from 2 kW in and 1.9 kW from 3 kW in, but this limit is based on current, not power. If you increase the voltage, you can get more power for a given current and thus higher peak power (at higher speed). How long you can maintain this peak depends on the thermal limits above.
There's also a limit to how much torque the motor can put out, which is based on the magnetic properties of the motor. This is the point where you'll get 1.8 kW from 2 kW in and 1.9 kW from 3 kW in, but this limit is based on current, not power. If you increase the voltage, you can get more power for a given current and thus higher peak power (at higher speed). How long you can maintain this peak depends on the thermal limits above.
You really only care about the winding temps, not the motors case temp. At higher speeds, the case is generally cold, and the windings can be 100ºC+...
Unless you want to open the motor and put a temp probe directly on the windings, get an idea for what the motor can take based off its size. Look around for what other motors are rated at, and compare them to yours. If it looks similar, the ratings are likely similar. Then you can start off near the stock power ratings and step them up from there. Don't just dive in at a few kW and hope for the best, unless you have some experience. It all depends on how its used.
Unless you want to open the motor and put a temp probe directly on the windings, get an idea for what the motor can take based off its size. Look around for what other motors are rated at, and compare them to yours. If it looks similar, the ratings are likely similar. Then you can start off near the stock power ratings and step them up from there. Don't just dive in at a few kW and hope for the best, unless you have some experience. It all depends on how its used.
Sorry my gf was bugging me for being on my phone while in the grocery store. What I ment was HP ratings of motors.tdneVmoDK said:
Typicaly if its rated to say 1hp you can spike it with 8-10x that for 10-30 seconds at a time. But Im not sure if you can get 8-10x the hp out.... or if you are just getting some more out minus increasing losses.... IM working on my motorcycle dyno should have it done in ~ two months so I can gather more data.
miro13car
100 kW
from frst post-
" how many watts it can produce..."
it draws watts of power from battery when it runs converting electrical energy to mechanical energy.
Consumed power is basically rate at which electrical power is converted at ALL PMDC motors should burn/destroy itself when pushed to the limits.
" how many watts it can produce..."
it draws watts of power from battery when it runs converting electrical energy to mechanical energy.
Consumed power is basically rate at which electrical power is converted at ALL PMDC motors should burn/destroy itself when pushed to the limits.
parabellum
1 MW
Magic?miro13car said:
Alan B
100 GW
The motor is not indestructible, but the controller may be programmed to protect it and prevent damage. The system is protected.
parabellum
1 MW
Right, like almost every commercially available system is limited slightly under the capability of its weakest component.Alan B said:
miro13car
100 kW
Think before jump and start posting.
Read carefully before responding to a thread.
Repeat,
those motors TF and Eplus cannot be electrically destroyed,
I said ELECTRICALLY , read carefully , not mechanically, you can smash against the wall everything and destroy of course.
why ?
Knowledgable people already know why.
Read a little more on BLDC motors and controllers before jumping in.
Yes, they have limits, those limits are overvoltage, overcurrent, overtemp. protecions,there are easly available electronics to execute such protections, but that cost$$$, not on $300 motor for sure.
So no BS here.
those motors will not allow you to damage them.
Read carefully before responding to a thread.
Repeat,
those motors TF and Eplus cannot be electrically destroyed,
I said ELECTRICALLY , read carefully , not mechanically, you can smash against the wall everything and destroy of course.
why ?
Knowledgable people already know why.
Read a little more on BLDC motors and controllers before jumping in.
Yes, they have limits, those limits are overvoltage, overcurrent, overtemp. protecions,there are easly available electronics to execute such protections, but that cost$$$, not on $300 motor for sure.
So no BS here.
those motors will not allow you to damage them.
miro13car said:
Electronic circuit protectors, temp probes and other protection devices are dirt cheap
.Give me one of those motors, and I'll electrically destroy it. I have my methods (maybe coupling it to my induction heater, that would certainly give some interesting results
)Edit: Eplus bldc motor has internal controller running a FOC algorithm, this is a system - not a motor. Go read up.
parabellum
1 MW
Again, almost every cheap motor can not be electrically destroyed working under its specifications in its system. That why you can feed 10kW in 500W rated motor or 200V in 36V rated motor. It even can work at this and much more monstrous specs continuously if you can keep the system cool enough.miro13car said:
oatnet
1 MW
Miro, you know I am a big fan of TF/E+ - but I could put enough voltage through it to pop the controller, and with a different controller I could put a big load and enough current through it to fry it.
In addition, tdne is correct, the work produced my an electric motor can be measured in Watts.
tdne, I mostly posted to uselessly nit-pick at your thread's title - a combustion engine can be called a motor, but an electric motor can't be called an engine.
-JD
In addition, tdne is correct, the work produced my an electric motor can be measured in Watts.
tdne, I mostly posted to uselessly nit-pick at your thread's title - a combustion engine can be called a motor, but an electric motor can't be called an engine.
-JD
