Wiring a single Phase Mag starter

[TDKPE]

It's got my interest, that's for sure.  I'd love to ring out the connections and see what's what.

[Roly]

How about this drawing from Shihlin.  Looks like identical drawings.   They are separate sets of contacts so they don't have a common built in. There are two sets of contacts on the right side but not shown on this drawing Roly

[brianwelch]

First attempt at posting a pic:

[TDKPE]

That's helpful.  The A1 conductor passes through the overload unit, so no doubt the A1 and A2 terminals are the contactor's coil terminals.  

It's possible the NC and NO sets on each side are their own commons, in a manner of speaking - 21/22 have continuity (to each other) and 31/32 also.  13/14 and 33/34 would have no continuity until the contactor is closed, at which point they would have continuity and the NC's pairs would lose their continuity.

I don't know that that's how it works, but with nothing else that could be called a 'common', that's all I can think of.  It's certainly quick and easy enough to check with a continuity light or multimeter, though.  

Can you check that?

Another possibility is that 13 and 21 are common with L1, 43 and 31 with L3, and so on with their nearest neighbor.

[Roly]

That's helpful.  The A1 conductor passes through the overload unit, so no doubt the A1 and A2 terminals are the contactor's coil terminals.  

It's possible the NC and NO sets on each side are their own commons, in a manner of speaking - 21/22 have continuity (to each other) and 31/32 also.  13/14 and 33/34 would have no continuity until the contactor is closed, at which point they would have continuity and the NC's pairs would lose their continuity.

I don't know that that's how it works, but with nothing else that could be called a 'common', that's all I can think of.  It's certainly quick and easy enough to check with a continuity light or multimeter, though.  

Can you check that?

Another possibility is that 13 and 21 are common with L1, 43 and 31 with L3, and so on with their nearest neighbor.

The drawing for that contactor disappeared from yesterday.   There are 4 independent sets of contacts 13-14,21-22,31-32, and 41-43.   Nothing is common on the contacts.

[Roly]

Different contact numbers on right.   Post above should have contact 43-44 not 41-43 Roly   Hope the image works today

[TDKPE]

The drawing for that contactor disappeared from yesterday.   There are 4 independent sets of contacts 13-14,21-22,31-32, and 41-43.   Nothing is common on the contacts.

Where did that come from?  


 

That certainly explains why it's wired the way it's wired, except for using 14 as a junction (could just have the customer use A2 directly, but it does simplify wiring a PB start/stop station.  Just wire 13 to the Stop button to break continuity when it's energized.  The pressure switch would be the Start button, and both need to be momentary switches.  Easy peasy.

[brianwelch]

Front and back of the switch...Just noticed the numbering the terminal side of the switch... Is it as simple as landing 13 to 13 and 14 to 14? I don't see a 23 or 24 on the mag starter. Does the A1 (top right) go to same on the starter?

[Roly]

Where did that come from?  


 

That certainly explains why it's wired the way it's wired, except for using 14 as a junction (could just have the customer use A2 directly, but it does simplify wiring a PB start/stop station.  Just wire 13 to the Stop button to break continuity when it's energized.  The pressure switch would be the Start button, and both need to be momentary switches.  Easy peasy.

Don't forget about a holding contact.   Roly

[TDKPE]

Don't forget about a holding contact.   Roly

Replace pressure switch with start button, and add stop button.  Contact set 13-14 is the holding contact, which is probably why it's pre-wired that way from the factory.

   

Edit: Sorry for the crude sketch, but I had to erase the pressure switch in MS Paint, print to a PDF, insert that into AutoCAD, add the momentary switches, then do a screen capture.  Probably should have gotten rid of most of the yellow first, but was too lazy to keep going back and forth to make it pretty.