https://www.aliexpress.com/item/NEW...11237.html?spm=2114.10010108.1000023.1.jILm8k
$us 46.39
$nz 63.44 free ship.
This looks like an appropriate unit to use. The motor is 12V, 700W rated, potential start current - massive?
free speed = 1500 rpm.
1) Can I monitor and limit current demand? Above 80A, controllers get expensive.
The load requirement is only 42 J (150 N x 0.28 m at steady speed)
I possibly want x 3 times the current to get adequate acceleration torque.
if this takes 2.3 secs at 750 rpm, this is 18 watts - for 42 J very small;*** x 3 = 54 W***
Such a big motor would run at a higher rev point, so we could easily double
the output power-to say 108 W ??? less time, more power.
This is 3x the base power to get the correct current estimate.
What is the current needed to get the correct torque? Permanent magnet brushed motor:
If this was a standard motor, at 60% efficiency, this would need 15 amps. This probably doesn't
need to use vastly more, but doesn't run as fast at maximum load- maybe 750 rpm at full power (half speed)?
as torque is directly related to amps.
The maximum power current of 50A would do me as a starting current as well
The driveline would probably work OK with a lot less than 50 A.
Can anyone identify the type of controller they are using? is it digital? can I directly input
a PWM signal? I have found a nice digital tacho unit. How would I set a control strategy to
limit output current? would I need extra electronics?
Does my reasoning re output sound correct?
700 W would need 120A at 50% efficiency, so potential starting current is very likely
x 2 or more - over 240A potential!. Definitely fryup material!
Torque and current is generally linear through the maximum power point at 50% speed, for
permanent magnet motors.
Does running at 50% of no-load speed mean 50% efficiency?
Do I need bridging flyback diodes and capacitors? How do I work out the correct
ratings?
Can I get a lower rated motor that would do the job?
It would be lighter- this one is about 3 kgs.,
price is fairly cheap: $150 nz delivered.
I need about 1 N-m at maximum power, free speed 1500 rpm, 12V
I will check Aliexpress.
cross-check : 10mm lead at 450N = 4.5 J
T = J/2pi = 0.72 N-m, 78 rad/s, w x T = P = 56 W - does this sound about right?
$us 46.39
$nz 63.44 free ship.
This looks like an appropriate unit to use. The motor is 12V, 700W rated, potential start current - massive?
free speed = 1500 rpm.
1) Can I monitor and limit current demand? Above 80A, controllers get expensive.
The load requirement is only 42 J (150 N x 0.28 m at steady speed)
I possibly want x 3 times the current to get adequate acceleration torque.
if this takes 2.3 secs at 750 rpm, this is 18 watts - for 42 J very small;*** x 3 = 54 W***
Such a big motor would run at a higher rev point, so we could easily double
the output power-to say 108 W ??? less time, more power.
This is 3x the base power to get the correct current estimate.
What is the current needed to get the correct torque? Permanent magnet brushed motor:
If this was a standard motor, at 60% efficiency, this would need 15 amps. This probably doesn't
need to use vastly more, but doesn't run as fast at maximum load- maybe 750 rpm at full power (half speed)?
as torque is directly related to amps.
The maximum power current of 50A would do me as a starting current as well
The driveline would probably work OK with a lot less than 50 A.
Can anyone identify the type of controller they are using? is it digital? can I directly input
a PWM signal? I have found a nice digital tacho unit. How would I set a control strategy to
limit output current? would I need extra electronics?
Does my reasoning re output sound correct?
700 W would need 120A at 50% efficiency, so potential starting current is very likely
x 2 or more - over 240A potential!. Definitely fryup material!
Torque and current is generally linear through the maximum power point at 50% speed, for
permanent magnet motors.
Does running at 50% of no-load speed mean 50% efficiency?
Do I need bridging flyback diodes and capacitors? How do I work out the correct
ratings?
Can I get a lower rated motor that would do the job?
It would be lighter- this one is about 3 kgs.,
price is fairly cheap: $150 nz delivered.
I need about 1 N-m at maximum power, free speed 1500 rpm, 12V
I will check Aliexpress.
cross-check : 10mm lead at 450N = 4.5 J
T = J/2pi = 0.72 N-m, 78 rad/s, w x T = P = 56 W - does this sound about right?