Make a search for "magnetic contactor" - that's the correct term for
switches used for most woodworking machines. Andy gave a pretty
comprehensive description. Motor starters are contactors for use when
the motors don't have integral overload devices. Starters combine a
contactor with an overload device and an incoming line disconnect
device (either a fused switch or circuit breaker).

Hope this helps,
John Sellers

"Joe User" wrote in message
...
I wast just browsing a DC thread where "magnetic switches" are
discussed. Not the first time I've seen the term, and I know what
they
were talking about, but I DAGS and the first 40 or 50 hits mostly
related to burglar alarm type switches, and none referred to the
"punch
red for off, punch green for on, don't power the tool up after a
power
failure" type switch that makes sense for woodworking and other
machinery. Grizzly's web site lists them as magnetic switches, but a
search at Grainger's web site for "magnetic switch" returned alarm
type
switches and relays, and at McMaster-Carr returned alarm switches.
I
didn't keep searching very long, so I didn't find what I was looking
for
at either site.

I guess what I'm getting around to is a question: Is there another
name
for this type of switch?

They're very simple devices. The actual switch for power to the
tool is
a relay. The relay's coil gets power either through a set of
contacts
on the relay itself, or applied via a normally open momentary
switch
(the "on" button). A normally closed momentary switch in series
with
the coil power is the "off" switch.

A relay with a 110VAC coil and appropriately rated contacts, a NC
pushbutton (red for off) and a NO pushbutton (green for on) and an
appropriate enclosure are all you need to make one of these.

If one wanted a separate start/stop switch for the dust collector at
every tool, it would be easy for the electrically inclined
woodworker to
build a switch that would support a remote start/stop pair for the
DC at
every station. All of the start buttons would be in parallel, while
all
of the stop buttons would be in series (this could be obnoxious if
you
have a bad connection on the "stop" side). I'd probably use a 24VAC
for
the control side, which would mean a 3 pole relay or an extra 24VAC
transformer.

There are also current sensing controls. Attach one of these devices
to
a power wire on a tool (there is no electrical connection, it senses
the
magnetic field caused by the current flowing through the wire) and
use
it to apply power to the DCs relay. I couldn't find these right off,
either. anyone know what they're called?

just random thoughts and questions....

-j