"ATP" wrote in message
...
Steve Koschamnn wrote:
Hi Group:

I am trying to wire a heavy duty push button switch. (push for on,
push the other button for off). I am planning to switch a 3 HP 220V
1 Phase motor for my homebuilt drum sander. The switch is rated for
220 Volts, 30 amps, which should be fine, as the motor pulls only 16
ams.

The swith came from someone's junk pile (mine...vbg), as did most
of the parts for this drum sander. Now that I have a finally use for
this switch, there is no schematic in the switch box. There are
two, spring loaded push button blocks with each block having 4 screw
in terminals. Two terminals are on the "upper block or top plate,"
where the plunger is mounted, and two on the lower block (bottom
plate) that the plunger contacts. The plungers are in the middle of
each terminal block.

OFF BUTTON ON BUTTON
BLOCK BLOCK
0 0
0 0
0 0
0 0

Top Bottom Top Bottom
Plate Plate Plate Plate

Pushing each plunger contacts the lower block, but when released,
both pop back up. I am assuming you need to jumper somehow between
the OFF block and the ON block terminals, but which ones? Oh, and
by the way there is a panel light that uses 125 volts to light...I am
not planning on running two hots PLUS a neutral, so I think the light
is out...

THANKS for any help..

Steve Koschmann

Start/Stop or On/OFF pushbutton switches are usually used with a separate
magnetic contactor. The start button (normally open) provides momentary
power to a holding coil. Once the coil pulls in, it stays energized via
its
own auxiliary contact unless the (normally closed) stop button is pushed
in.
Stop buttons are wired in series with the power to the coil so that any
stop
button will drop out power to the coil. The older, self contained
start/stop
controls that don't work with a contactor typically stay in when you push
them and don't have the safety features inherent in a start/stop circuit.



http://www.ee.polyu.edu.hk/staff/een...2/chapter5.htm

Some pretty good schematics towards the bottom of the page.

--

SVL