FILENAMES:

start-stop.20001.jpg
start-stop.20002.jpg


DESCRIPTION:

These are diagrams of start/stop switch connections. 

Posted by James Glass <jglass51@hotmail.com>.  

The following description was provided:

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Hi;

There have been so many questions posted about start/stop 
switching circuits, I decided to show one that I have used 
many times.    The relay shown in PIC 0002 has a 120 volt 
coil.   In other words, 120-v single phase will energize 
the coil.  Notice at the far left the white wire (neutral) 
connected to terminal A2 and the purple and yellow to 
terminal A1.   120 volts applied energizes the coil.     

For clarity, the three phase wires are not connected at 
terminals L1, L2, L3.    An overload relay is also shown 
but not always required, depending on what the motor 
contactor is switching.     Note the yellow wire connected 
to L2.   This wire will tap into one leg of the three phase 
to supply voltage for the contactor and buttons.

The actuating button shown is a push/pull spring return.    
When the button is pulled momentary voltage is supplied to 
the coil at A1.    The purple wire is also energized and 
supplies the coil with voltage after the  pull button is 
released and becomes a “holding circuit” through terminals 
#13 and #14.    The purple wires run to the push/pull button 
to a normally closed contact.   When the push/pull button is 
pushed  “in” voltage is interupted to the purple wire and 
the coil opens.     2 buttons could be used with this circuit.   
One advantage to this circuit is, if there is a general power 
failure, the coil (contactor) will require manual starting   
when the power returns.

In the drop box @metalworking.com a schematic is shown in 
start-stop 0001 with part numbers of the parts used.   The 
contactor and OL is Allen-Bradley  and the button and contacts 
is Cuttler-Hammer.

Hope this helps.
Jim