Re: home built controller help

Sorry...I read it 5 times and still didn't see that they are

__6 Wire Motors__

Which means they are unipolar
which can be made to run bipolar (but not the other way around)

With an ohmeter...do a continuity check on the wires

When you find a wire that has continuity to 2 other wires...
this is the center tap....mark them and put them aside...there'll
be 2 of them.

Of the four wires left, find the ones that have continuity to each
other....these are the motor coils.

Measure the resistance of each coil. They should be the same(or
very close).

I would make a few Assumptions here....
They were running at 24 volts. So I'd divide that by 20, which
equals 1.2 volts.....my guess would be that that is the motor
rating.

So I'd divide 1.2 volts by the coil resistance to get the
current rating (or the Max. Amps for the motor)

I would guess that would be anywhere from 2 to 6 amps(could be wrong
though!!).

To do the Gecko resistor calc's, you'd decide how many amps you
want to give the motor. This has nothing to do with the voltage.

I use about 75% of the motor rating, simply because the motors
get HOT and it worries me sometimes.

So let's say the motors were rated 4 amps(Example).

I'd feed it 3 amps to start with(personal preference...75%)

47000 multiplied by 3(amps you desire)= 141000

7(amps max gecko rating) -(minus) 3(amps you want) = 4

141000 divided by 4 = 35250(the resistor you'd want).

You'd use the closest rated 1/4 watt resistor.
Probably 33K

This is Only how I'd do it. There are many others here who know
much more about it than I do. If I'm wrong or missing something
it'll be pointed out soon enough and I don't mind being corrected.
(Cheaper than ruining stuff!)

John)









--- In CAD_CAM_EDM_DRO@yahoogroups.com, "carlosandpeppes"
<carlosandpeppes@...> wrote:

>
> Hi all,i am building a controller along the lines of the one shown in
> home shop machinist using a pmdx 131 board,3 212 geckos,40v 10 amp
> power supply.
>
> I have very limited info on the motors that i am using,such as voltage
> and amperage,but 2 are nema 34 3.7 inches long 3.5 n/m,and one is nema
> 34 2.45 inches long 1.5 n/m,all are six wires.They were originally
> getting 24 volts.
>
> I have limited knowledge of electronics,so a step by step way of
> testing motors would be nice and also how to configure the several
> jumpers on the geckos and breakout board,and the current set
> resistors.thanks in advance!
>