Re: [CAD_CAM_EDM_DRO] blown fuse

Keith Clark wrote:

>I was happily running my mill with Mach2 when the fuse for the
>powersupply to the steppers blew. I was cutting with a coromill 3.0
>inch bit with 6 inserts on hard metal. I am worried if it is
>expected that one motor could blow a fuse if under load. I have
>Geckos with a 75v 16 amp powersupply. I can't seem to find any
>other problem
>
>

There are a couple of possibilities. one is that the fuse was marginal, and
failed in the slow-heat mode. If so, you may find the fuse has a melted
solder look on some part of the element. If it failed in hard overload
mode, it likely indicates that a component has failed, and another fuse
will blow instantly. Hard overloads will often leave the inside of the
fuse tube covered in vaporized metal.

What is the rating of the fuse that blew? Is it on the AC input to the
transformer? Full load is roughly 1200 W, which would draw 10 A if
the power factor was perfect. Since it won't be anywhere near perfect,
a full load on such a power supply may cause an RMS current draw
that could even exceed 15 A.

Jon