voltage selection

[Claude Boudreau]

Well I ve been waiting long enough, ordered and received my gecko 540 with the 320 oz in motors this week.
First question, acording to the formula for voltage 32 x sq root of inductance = V
comes to 32 x sq rt 2.8 mh =45.1volts., is it close enough, or is it beter to somehow lower the 48 volt from the furnished power supply ?
There is a trim pot, but I havent tried it yet.

Second question: on gecko documentation it is stated that if your phase current is 3.5 or higher that no resistor is used.
that seem to contredict this...
320 oz in 2 8 MH NEMA 23 Stepper Motor 3 8" Shaft for CNC Router Mill | eBay

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[aarggh]

Hi Claude, I think you may have missed a number there, 53VDC is actually the max voltage for a 2.8mH stepper, so the 48VDC power supply will be perfect for you, and with the G540 will give fantastic performance and results.

There are a number of people who do put the resistor in, and those who don't, but I always put them in myself, just so it is current limiting anyway. If I remember right there was also something about a difference in mode or settings when a resistor wasn't used to current set. I'd have to go over the documents again to refresh my mind there.

cheers, Ian

[john-100]

Hi Claude


with or without the 3K5 resistors , the maximum motor current output from the G540 is 3.5A

the difference is the current set resistor has to be fitted for the stepper drivers to go into standby and reduce the motor current when the drive is idle

John

[aarggh]

Hi Claude


with or without the 3K5 resistors , the maximum motor current output from the G540 is 3.5A

the difference is the current set resistor has to be fitted for the stepper drivers to go into standby and reduce the motor current when the drive is idle

John

Ahhh, thank you John! The idle mode was what I couldn't remember!

cheers, Ian

[Claude Boudreau]

you are right , using my small computer calculator witch I cant seem to be able to enlarge , I type square cube.lol old eyes.
As far as the resitances they say it is integrated in the DB9 connector These dont seem to be the type that you can take apart so
I will have to measure with a ohm meter.
another little thing I ve read somewhere that these 540 are easily servicable in order to replace a g250 in the future, how do you open that metal
cover it seem to be snapped in place ...

[john-100]

Hi Claude

the G540's case just clips together
you need to carefully spring open the top of the case to clear the tabs on the bottom half



Note - the new version 3 of G250 used in the latest version of the G540 ( ver8) has been redesigned to move the potentiometer from the G250 driver
and to the G540 mother board



John

[Claude Boudreau]

thats what happen , was watching a utube video yesterday where they had a hard time adjusting that pot deep in the hole while I could see them clearly on my 540.

as far as the resistance is concerned It would be embeded in the motor db9 connector, invisible and unchangeable without changing connector right?

Hi Claude

the G540's case just clips together
you need to carefully spring open the top of the case to clear the tabs on the bottom half



Note - the new version 3 of G250 used in the latest version of the G540 ( ver8) has been redesigned to move the potentiometer from the G250 driver
and to the G540 mother board



John

[aarggh]

thats what happen , was watching a utube video yesterday where they had a hard time adjusting that pot deep in the hole while I could see them clearly on my 540.

as far as the resistance is concerned It would be embeded in the motor db9 connector, invisible and unchangeable without changing connector right?

Hi Claude, yes the resistor must always be at the DB9 end plugged into the G540, never at the stepper end, so many suppliers have them fitted inside the DB9 shell. it will be easy enough to measure with an ohmmeter.

cheer, Ian

[Claude Boudreau]

Ok. measured 3.38k at the male end of the cable,probably the nearest value available. I will have to remember, if an extention ever needed, to install it at the other end.
thanks.

Hi Claude, yes the resistor must always be at the DB9 end plugged into the G540, never at the stepper end, so many suppliers have them fitted inside the DB9 shell. it will be easy enough to measure with an ohmmeter.

cheer, Ian