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Topic: its possible a stepper go that fast? (Read 5430 times) previous topic - next topic

rmetzner49

Quote
i took my amp meter, and snap it on one of the four leads, but most be something worng, its reading only .263A, maybe the snap it just to AC


If your amp meter is the clamp on type, you were only reading the current's  AC component.  From the schematic, I see there is a 0.1R resistor marked "sense" for each phase.  Try reading a voltage across the resistor.  With your voltmeter you will get a more meaningful representation of the current, although still not completely accurate.  The meter will read an average DC value but will just average out the PWM chop.


Robin2




i have a current limiter at 2.0 amp per fase,


yes its a proper driver maded for somebody of the forum, it was maded for cnc, based on the DRv8025


I'm not sure if you are using the DRV board to limit the current or if you have some other current limiting system on your power supply.

By the way, should that be DRV8825? I can't find a dataseheet for a DRV8025

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

KenF

Are you attempting to go direct from a standstill to over 800 steps per second?  If so, I'd suggest that's another issue.   Try to ramp up the speed more gradually.  Once it's at 800 steps per second, THEN move the step rate up and see what happens.

copachino

#18
Oct 20, 2014, 10:47 pm Last Edit: Oct 20, 2014, 10:51 pm by copachino
i have a current limiter at 2.0 amp per fase,
yes its a proper driver maded for somebody of the forum, it was maded for cnc, based on the DRv8025
I'm not sure if you are using the DRV board to limit the current or if you have some other current limiting system on your power supply.

By the way, should that be DRV8825? I can't find a dataseheet for a DRV8025

...R
sorry it was a typo error, driver its drv8818 from texas

http://www.ti.com/lit/ds/symlink/drv8818.pdf

also, yes im using driver on board current limiter option

copachino

Are you attempting to go direct from a standstill to over 800 steps per second?  If so, I'd suggest that's another issue.   Try to ramp up the speed more gradually.  Once it's at 800 steps per second, THEN move the step rate up and see what happens.
no, im using a pot, to ramp the speed, sstarting at 50Steps/s, and then going at max speed at 2400steps/s max, i can get more than that with 12v and 2A per fase

Robin2

no, im using a pot, to ramp the speed, sstarting at 50Steps/s, and then going at max speed at 2400steps/s max, i can get more than that with 12v and 2A per fase
Maybe it's because this is a long Thread but I'm confused.

If you can get it to go up to a max speed beyond 2400 steps/s (you don't say the actual max) what exactly are you not able to do that you want to do?

Presumably it will go even faster if you use 35volts.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

copachino

no, im using a pot, to ramp the speed, sstarting at 50Steps/s, and then going at max speed at 2400steps/s max, i can get more than that with 12v and 2A per fase
Maybe it's because this is a long Thread but I'm confused.

If you can get it to go up to a max speed beyond 2400 steps/s (you don't say the actual max) what exactly are you not able to do that you want to do?

Presumably it will go even faster if you use 35volts.

...R
i want speed, about 1500RPM its possible, but is hard to get the most fast i can got its 720 RPM(2400steps/s), but i was thinking if its only power that i need, or something about programming, but its hard t ge a power supply more than 12V, maybe i will have to make my own, and wind my own transformer, to get the 36V and about 6AMP


Robin2

its hard t ge a power supply more than 12V,
That seems extremely unlikely - unless it's a local issue where you live.

I imagine Ebay has plenty of them - for stepper motors.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

copachino

#24
Oct 23, 2014, 12:30 am Last Edit: Oct 23, 2014, 12:35 am by copachino
its hard t ge a power supply more than 12V,
That seems extremely unlikely - unless it's a local issue where you live.

I imagine Ebay has plenty of them - for stepper motors.

...R
in fact yes, its really hard to get a supply in here, ebay yes i thought i could look but shipping to my country its about the same or more thatn the actual price of the supply

rmetzner49

The best I've seen a NEMA23 Bipolar motor do is 5,000 Steps/Second with a 65VDC Supply @ 5 Amps. 

You need a very low inductance motor as well, since at those frequencies it's almost impossible to get the current established in a given phase before the next pulse comes along.

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