[ropewrench]

i am replacing the slo~syns with the Vextas
I need new drives and power supply
What would you guys suggest

[ropewrench]

Ok i would like to use the vexta motors with a Gecko G540.
what would I need to get the best performance out of them using a 1/2 -10 acme?
i have a 24 volt power supply. but i do not remember the amps.
Would there be a better driver to use? ( i believe the G540 would give me more options ing the future)
Will 24 volts be enough for the 5.4v / 1.4 a motors?
How do I figure out the amps of my power supply or should I build/buy another?

[doorknob]

You have not provided much information, so it's hard to give any definitive advice. Do you have any more detailed specs for the motor? What is the intended application? What are you looking for in terms of performance?

Is there any reason in particular that you chose that motor? Did the Slo-Syn motor perform adequately, but it failed, or is there some other reason why you are replacing it? What drivers were previously in use?

That motor apparently has 6 wires, whereas the G540 is designed to drive 4-wire motors. You will have to make a decision about which of the 4 wires you will hook up, and then tape off the ends of the other two wires so that they can't get shorted out.

What kind of power supply do you have? Maybe a photo would help.

[ropewrench]

You have not provided much information, so it's hard to give any definitive advice. Do you have any more detailed specs for the motor?
Vexta 125oz/in Stepper Motor Specification
Model # PH268L-21
6 lead motor
1.5Amp/phase 5.4V

What is the intended application?
I have a 2" x3" I was running 2 motors on the the X with 1/4 - 20 allthread"slo~syns too week" I am swithing the X to one motor

What are you looking for in terms of performance?
Faster than 6 IPM

Is there any reason in particular that you chose that motor?
I have them already

Did the Slo-Syn motor perform adequately, but it failed, or is there some other reason why you are replacing it?
They are wimpy I think they are .30 oz i was running them on at 24 volts

What drivers were previously in use?
based on the L297 controller "John Conrad Kleinbauer "

That motor apparently has 6 wires, whereas the G540 is designed to drive 4-wire motors. You will have to make a decision about which of the 4 wires you will hook up, and then tape off the ends of the other two wires so that they can't get shorted out

Thinking a G540 would give me room for an upgrade later.
I am open for suggestions and options

What kind of power supply do you have? Maybe a photo would help.

I built it awhile back and do not remember the amps
There is no markings on the transfomer
I get 0.1 resistance on the seconary
hope this helps

Thanks

[doorknob]

I am not sure that I can give you adequate guidance, as there are still some unknowns about the motor. For example, we do not know the winding inductance. Perhaps someone else who has experience with similar motors could chime in. But you could certainly give it a try.

The G540 would seem to give you options for future upgrades.

The power supply looks like it should be more than adequate to run your motors. One way to figure out how much current you can get from the power supply is to hook up some different test loads to it and measure the output voltage under load (to verify that it does not drop too low). The transformer looks hefty enough that it ought to be able to easily handle at least several amps (and probably a whole lot more). The BR2510 diode bridge has a maximum current rating of 25 amps, so you should be good to go with it.

[ger21]

A HobbyCNC drive for $70 will be your cheapest option.
As a guess, with those motors, 24V, and 1/2-10 acme, your looking at maybe 30ipm best case.

The G540 might give slightly better performance, but unless you change motors, screws, and power supply as well, you're just spending 4x more than you need to.

[ropewrench]

Thanks guys
I ordered the hobbycnc pro figuring the money savings "g450" + the Idle Current Reduction I am still ahead.

So I am planning on useing the power supply I already have.
How musch trouble could I expect if it is under Amped.

I used power resistors on my first board
Will i be needing them on the hobbycnc board?

Thanks

[ger21]

No resistor needed. Torque is proportional to current. The less current you supply, the less torque you'll have.

[ropewrench]

Dave was fast (about 3 days for delivery)
Finished the HobbyCNC PRO Kit (about 3 hours)
Test came out 5volts

[ropewrench]

Out with the OLD and in with the NEW

OLD


NEW
However I am having a problem with the Current Adjustment.
I can not seem to achieve .21 volts. I can get much higher readings
Is it me
My meter
or am I backassward

[doorknob]

Out with the OLD and in with the NEW

OLD


NEW
However I am having a problem with the Current Adjustment.
I can not seem to achieve .21 volts. I can get much higher readings
Is it me
My meter
or am I backassward

I think that I see your problem.

You should be using the 18-year-old Glenlivet, not the 12.

Also, from your photo I can not tell what your meter is set to or whether you have the probes connected to the proper test points.

OK, it looks like your Fluke meter is auto-adjusting. While I generally like and respect Fluke equipment ('if it works well, it's a Fluke'), I'm greatly suspicious of readings taken with that particular auto meter. The display shows that the meter thinks it is supposed to be reading resistance (ohms), but you should instead be reading volts.

Can you get hold of a cheap Harbor Freight meter, put it on the lowest DC volts scale, and report the reading?

[ropewrench]

My thinking too
It should have been the 18 yr
However this is a budget build and we gota use what we have.

The Fluke is a auto so I do not have settings.
My other meter is toast. Brother in law

Ok off to harbor Frieght

Check back later

[ropewrench]

got a meter and it seems right
All 4 adjusted to .21 for 1.5 amp motors

[ropewrench]

One motor hooked up and seems to be good

[ropewrench]

Gota love the prices
99 cents for 8 ft of shrink

[ropewrench]

Here we go
I put the controller box together With the the power supply
Checked wires refitted everything.

Crossed my fingers and powered up

They started Hissing at me. Shut it down and looked it up
SAFE.

Hopped into Turbocnc and started setting It up

X putter and erratic Ramped up the numbers and it smoothed out
Y ran like a top

Z Doesn't spin. Locks up on power up
Pulled the board to re check solder Again.
Found one of the Mosfits on Z was backwards.
Flipped it and tried it again.
Z is still down

What kind of damage did I do?

KellY

[john-100]

which fet did you put in the wrong way round Q5 or Q6 ?
they are both in the auto current reduction circuit

damage to Q5 would affect the control of the SLA7078M pins 17 (sync) and pin 13 (V ref)

Q6 just controls the ref volytage to pin 13

if Q5 is working you should see the voltage on the positive terminal of C 17 change as you step the Z axis

its possible one of the 6 inverters in U9 (74HC14) has been damaged if an output was connected to the +5V supply by the reverse connected FET


John

[ropewrench]

Thanks John

It was Q5

and I have 5 volts at positive terminal of C 17 to, but no voltage change while moving Z

What are my other checks

Thanks Kelly

[john-100]

to test your board
when the Z axis is not being stepped the voltage at C17's positive terminal
should be at a logic 0 ( no more than +1V)

this is the input to U9 pins 3 & 5 and the outputs on pins 4 & 5 at logic 1 , that shouild be more than + 2V (typically 4V)

with a logic probe you should find the Z axis step pulses on U9's pin 1 and
the inverted step pulses at pin2 which is connected to Q5's gate terminal

if you only have a voltmeter you may be able to see a change in voltage
at pins 1 & 2 if you step the Z axis at a high speed

to test the logic levels on U9 pins 1 & 2
it could be easier to see if you changed mach 3 to send the direction signal
to the Z axis step output , printerport pin 7(?)
check the level , change the "direction" and the level should change 0V to 5V or 5V to 0V

if U9 works OK you could remove Q5 and use a wire link to connect the source and drain connections until you can replace Q5 with another BS250P FET
if you don't see any change at U9 pin1
it could be U 9 is faulty and Pin 1 is short circuited within the IC
or you have a problem with the printerport or the SLA7078M stepper IC
sockets for the 74HC14 IC's would of made things easier

if you look at the X axis
the step signal connects to U8 pin 1
the inverted step signal ouput from pin 2 is connected to Q1
when you step the X axis you should see the voltage on the positive terminal of C 15 rise from logic 0 (0V to +1V) to logic 1 (+2 to +5V)
this is voltage is connected to U8 pins 3 & 5

when you have a logic 1 level at U8's pin 5 pin 6 goes to logic o , thats Ov
and this switches on Q2
this connects +5V to R1 and this increases the ref voltage to the X axis



for the Z axis
when you have Q5 working or its replaced with a link connecting the source and drain terminals you should find U9 pin 6 goes low
this switches on Q6 to connect +5V to the junction of R17 & R19
increasing the ref voltage at TPZ

John

PS do you have the circuit diagram for the board ?
http://www.cnczone.com/forums/joes_c...c_-_mach3.html

I must have a look to see why I'm not getting the email alerts

[ropewrench]

Here goes
when the Z axis is not being stepped the voltage at C17's positive terminal
should be at a logic 0 ( no more than +1V)

C17 is 5 volts but so is C15 C16 and C18

I do not have a probe

And there is a problem with the LPT port

I am using turbocnc / Dos

Z step 7 No change 3.357 v
Z direction 6 No change 3.357 v

X step 3 3.367 v Drops while moving
X direction 2 OL to 3.365 v

Y step 5 3.367 v Drops while moving
Y direction 4 OL to 3.365v

I have another pci card wiht a 25 pin but I do not remember how to get it to boot in Dos
Windows sees it but doesn't have the drivers for it

Thanks