fusing Gecko leads ( was Re: 2 Fried G210's in a single day :-(

Hi,
Alan is suggesting this a safeguard until all is corrected. The
current draw will be low if everything is ok, but if there is a
short, the bulb will light and span (or bring) the supply voltage way
down to keep the mosfets in the SOA(safe op area) region. The bulb
will light up if you try to crank the G210's but thats ok, it just
makes the supply spongy. This trick has been around for years on TV's
and power amps during repair.

btw,
I used this tip( a 500w halogen shop lamp) for Inrush current
limiting/testing on my home wound auto-transformer. Later I got some
Megatherm NTC inrush limiters from the good people at www.amtherm.com
(free samples)
-Lee

--- In CAD_CAM_EDM_DRO@y..., "Carol & Jerry Jankura"
<jerry.jankura@s...> wrote:

> Hi, Alan:
>
> Out of curiosity, if you had a couple of amps flowing through the

lamp

> filament to drive the motor, what would prevent the lamp from

heating up and

> increasing its resistance. I know that the cold filament resistance

is

> negligable compered to the motor's, but the warm to hot resistance

is a

> different matter.
>
> -- Jerry
> |
> |are you advocating putting a fuse in each motor lead to a stepper
> |from each ouput line from a Gecko ?
> |
> |Since the fuse would add resistance, would you need any

compensation

> |for this ?
> |
> |also, if you add a lamp in the line between the cap/rectifier and

the

> |Gecko, aren't you reducing power ? the light would be neat, but
> |aren't you creating more of a drain than desired ?
> |
> |Dave