stepper motor stall?

[john swift]

whats the part number of your stepper motors ?

some thing like this from cnc4you ?

https://cnc4you.co.uk/resources/57HS82-3008B.pdf

with the coils wired in parallel the inductance of 2.5mH
is not too bad


some kits via ebay have motors with an inductance close to 9mH
that will make for a very slow machine with a 36V supply

John

[mancave newby]

hello john,thanks for the response,my motors are 4nm 60byg401-03,wired bipolar paralle,the drivers are set to 4.2 amps,1/10 step,iam using 2mm pitch lead screws at the moment,will change to ball screws when i can get the motors sorted,bought the kit from cnc4you,3 motors,3step drivers and 36 volt power supply,running mach3 licenced version,computer set to 25hz, regards richard

[Doddy]

Mechanical: Decouple the motor from the screw. Can you still stall the motor with the hand-wheel?, if so, then it's not likely the axis binding and I'd move to the electrics. With the system powered (i.e. steppers energised) can you turn the hand-wheels?

Electrical: Your PSU is 36V... have you measured the actual voltage though? Then repeat with the axis stalled.

From everything you've said you've not indicated lost-steps or loss of direction control - so the BoB sounds okay, as does the integrity of the wiring from the stepper driver to the motor.

Can you describe how you've wired the stepper (which colour wires go where).

Can you post the specification of the PSU?

Can you post the type of stepper drivers that you have? (a photo would be useful)

[mancave newby]

motor is direct drive to lead screw lh side of x,hand wheel on rh, yes can stall motors with hand wheels ,cant stall motors by exerting body weight pressure against x or y,can turn hand wheels when motors energised,resistance felt then clicking from motors.psu is set at36 volts ,have checked.wiring to motors is red and blue to a+,yellow and black to a-,white and brown to b+,orange and green to b- motors are 4nm 60bygh401-03 ,drivers are cw5045 supplied cnc4you, bob is a kk01, psu is marked as 36volts 400watt 11amp,sorry cant post pics until i find out how to do it,something else to learn. regards richard.

[john swift]

from your description I don't see any thing wrong

do you have the stepper driver enable inputs connected ??

if you do
try running with the enable disconnected
(the enable is a negative logic input so the drive is enabled with no input !! )

if Mach 3 is a bit slow enabling the drive that could be a cause of you missing steps


what position do you have switch 4 ?

if its off , the motor current will be reduced when the motor is idle

switched on , the current remains at the 4.2A you set the stepper driver to.
and you should feel more resistance when you try to manually turn the hand wheel



John

PS

if you have a JPEG photo on your desktop to add to a post

when adding a reply or editing a reply
click the symbol marked in red


on the next page click basic uploader
to add files from you computer

next page click browse
then type the JPEG file name in the box

[Doddy]

from your description I don't see any thing wrong

I quite agree. Thanks, Richard, for the reply. It does sound as though the steppers are underdriven... but I can't see any cause.Not sure about sw4 - you do say it stalls when operating so half-current setting shouldn't come into play. How warm are the steppers after a protracted period energised?, if not hand-hot then try upping the current setting on the drivers. After that I'm out of ideas.

You've not got any silly-long lengths of cable in the system?, no dodgy fine gauge cables to drop the supply voltage at the stepper driver?

Ah, one point - you still have the trapezoidal lead screws... ah - they will put a larger load on the steppers than a ballscrew... but you do use powerful steppers. Nope, I'm out of ideas.

[Clive S]

Just my 2 cents worth how big are the hand wheels because they will take a lot of inertia to drive them.

[mancave newby]

hello all out there,thought i would try to send some pics of my man cave,hear goes