Connection 2 & 3 of square D starter

[Jpflex]

What does connection 3 and 4 of starter go

I know one goes to coil and I thought one goes to direct power on all the time for when contacts close to hold them in?

Bottom connection interrupt return for coil during overload?

 

[augie47]

see pg 3-4

https://www.alliedelec.com/m/d/9fc525f61a23e121f6e13ae495f9fc4a.pdf

 

[jim dungar]

Control terminal 1 is the 'hot' conductor for the control power. This often goes to one side of the Stop button.
Terminal 2 is one side of a normally open contact used as a holding contact. This often goes to the other side of the Stop button and one side of the Start button.
Terminal 3 is the other side of the holding contact. This is wired to the other side of the Start button and is factory wired to one side of the Coil.
One side of the coil is not designated and is factory wired to one side of the normally closed overload relay trip contact.
Terminal 4, or COM, is the other side of the overload contact and goes to the other conductor/neutral of the control circuit.

 

[Jpflex]

Yes thanks. However on one starter there is an attached removable plastic switch called an electrical interlock. The mechanism rotated by a wheel to open contacts and moved by an opening in starter left side. I haven’t seen this on other starters I encountered. What is this for?

 

[jim dungar]

What you have is an 'external convertible interlock' as opposed to the fixed 'internal interlock' factory installed between terminals 2 and 3. I think all starters Size 3 and above use the external style for the holding circuit interlock.

The external version can be mounted on any of their NEMA starters whenever additional auxiliary contacts are needed.