Re: [CAD_CAM_EDM_DRO] Re: burning Gecko drive

Hi Keith,

It sounds like your motor must be numbered differently to mine. OK,
heres a safe if slightly long-winded method of finding the correct windings:

Get a car battery and two 12V bulbs. The bulbs should be the same rating
and somewhere between 21W and 55W. Make up two test leads as below.

battery + -----------------------

battery - -------bulb------------

Connect the + of one test lead to a motor terminal - it does not matter
which one. Now try the other end of the test lead on all the other
terminals until the bulb lights. Make a note of the terminal numbers and
try turning the motor. It should be fairly hard to turn. If it turns
easily then it has a shorted winding. Try all the other terminals. The
bulb should only light with one of the terminals. If it lights with more
than one you motor has an internal short. Now repeat until you have
found all 4 windings.

You have probably already done this with a test meter so you are
hopefully only confirming what you already know.

Leave the lead connected to one of the windings and connect the other
test lead to one of the other windings. One of three things should happen:

1) The motor shaft turns slightly with an audible click and the motor is
hard to turn by hand. You have found two opposite windings. These should
be OK to connect to the Geckos. To confirm this is correct, reverse one
of the test leads. The shaft should jump to s new position and still be
hard to turn.

2) The motor shaft does not turn or jumps then returns to it's original
position. The shaft is easy to turn by hand. These two windings are part
of a pair and are cancelling out. Do not connect these two to the Gecko
- you will may kill it.

3) The motor shaft does not turn or jumps then returns to it's original
position. The shaft is harder to turn by hand than before. These two
windings are part of a pair and are adding together. Do not connect
these two to the Gecko. To confirm these windings are part of a pair,
reverse one of the test leads. The shaft should now be easy to turn.

In cases 2) and 3), move the second test lead to another winding until
you find two opposite windings. Connect 1 winding to A+ and A- on the
Gecko and connect the other winding to B+ and B-. If the motor turns the
wrong way then swap over A+ and A-.

What supply voltage are you using? These motors are high inductance and
leed a high voltage to work well. I am getting 100IPM rapids at 75V.

Les




theokspindoctor wrote:

> Jon, I think I understand that the 210 will just make more steps and
> not fewer steps. I will keep working with the 201s for now. I hope
> you might look over this.
>
> Ok, just burned out my Gecko drive. the motor looks like this
>
>
> 3 2
> 5 8
>
> 6 7
> 1 4
>
> 2-8 one winding
> 3-5 "
> 6-1 "
> 4-7 "
>
> Originally it was wired as below to the Gecko by my installer. It
> worked that way but the maximum rapid I could get was 20 ipm
> phase A+ to 2
> phase A- to 1
> phase B+ to 8
> phase B- to 6
>
> I rewired it tonight as below and it burned it up. Why?
> phase A+ to 1
> phase A- to 6
> phase B+ to 2
> phase B- to 8
>
> Les Newell said his were wired as below and worked fine for him.
> Shouldn't his have burned as well? It looks the same as mine above.
> phase A+ to 2
> phase A- to 8
> phase B+ to 1
> phase B- to 6
>
> Anyone have any suggestions as to how it should be wired?
>
> Thanks
>
> Keith Clark
> clarkfamily5@...
>