Re: [CAD_CAM_EDM_DRO] Re: burning Gecko drive

----- Original Message -----
From: "Les Newell" <les@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Tuesday, August 17, 2004 2:05 AM
Subject: 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
>