# SMC-3 soft stater AB



## Dfresh64 (Sep 10, 2011)

*SMC-3 soft starter AB*

Wired up this starter can not get to energize. I can see that the starter is on and vibrating or humming . LED is green. 480 v 120 control voltage . Simple on start button off buttom . I believe the dip switches are in the correct position. Any suggestion it's got to be a simple over site. Thanks


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## John Valdes (May 17, 2007)

Is this a new application or one thats quit running?

Have you given it a command to start?

Have you checked to see if the input from the start button is being seen by the SS?

Is the stop circuit closed?

Lots more questions. You need to provide some more information to get any help.


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## JRaef (Mar 23, 2009)

What do you mean by "energize"? Is the motor connected? If not, no soft starter does anything that you can see. It needs a load in order to function. If you want to test it before connecting to the motor, use another motor (best) or 3 light bulbs, but shut it off quickly if it's 480V.


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## Dfresh64 (Sep 10, 2011)

New application 50 hp motor. Conveyor belt to load grain. Push buttons power goes through stop then to start then back to term board. The contactor has a hum to it. I guess energized is not the proper terminology. Yes it does have a load motor is connected. But it is on .I'm copying picture this should explain more. Thanks again


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## JRaef (Mar 23, 2009)

I see no wires on the load terminals. Like I said, "On" means nothing to a soft starter unless there is a load connected to it. The contactor that is inside only closes AFTER the SCRs are done ramping the motor to full speed. The SCRs must have current flow in order to function. No motor connected, no current flow, no ramping, no bypass contactor.


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## Dfresh64 (Sep 10, 2011)

Let me give a little more DETAILS . The picture is taken before I wired up. I have my 480 3 ph hooked to line and load then to motor. Didn't think I needed to share detail but I will include. Motor is wire. Controls,stop and start are wired per drawing. You said that I need a load . On my dip switches I moved it to the location where it. Should come on in 15 seconds? Is there something that I'm over looking ? Should I wait longer than 4 to 6 minutes ? Then turn the breaker off that feeds the control and motor ?


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## maddhatter (May 7, 2012)

A1 and A2 is Active / Neutral (always on - in your case potential 120V between two.)
In1 and In2 must both be energized (120v supply on both) for the starter to start.
97/98 13/14 are just fault contacts, NC and NO.

Edit: If it's vibrating / humming - chances are you dont have the FLC of the motor specified correctly in the DIP switches..


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## Dfresh64 (Sep 10, 2011)

So would u say that if I had the correct dip switches in the correct place. The motor should start ? Would u know what dip switches need to be on or off ?


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## maddhatter (May 7, 2012)

Dfresh64 said:


> So would u say that if I had the correct dip switches in the correct place. The motor should start ? Would u know what dip switches need to be on or off ?


What model is the SS and what size is the motor?


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## Dfresh64 (Sep 10, 2011)

The motor is a. 50 hp 3phase 480v 
The only info I have is its a SMC-3 Allan Bradley


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## maddhatter (May 7, 2012)

by the looks of it the dip switches shouldn't matter too much, (you should get some noise at least from the motor, worst case) did you read the manual? is it wired star or delta? really need pictures of how you've terminated it...


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## Dfresh64 (Sep 10, 2011)

I wil take a picture tomorrow . But it's just like the schematic in the picture. Minus the m1 part . I'm not aware what that is or goes to . Once someone tells me I know it is obvious.


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## micromind (Aug 11, 2007)

The M1 part is the coil inside the soft-start. 

Here's how it needs to be connected, assuming the control is 120AC. This will be noted on the soft-start nameplate. 

A2 is connected to the 120AC neutral. 

A1 is connected to the 120AC hot, and also to one side of the normally closed stop button. 

The other side of the stop button is connected to IN2 and one side of the normally open start button. 

The other side of the start button is connected to IN1. 

Make all voltage measurements with a digital meter, not a solenoid type wiggy. 

With the soft-start powered but not running, you should have 120AC from A2 to both A1 and IN2. If it is present at A1 but not IN2, most likely the stop button has the wrong contact. It needs to be closed and open when the button is pressed. 

Once this is good, there should be no voltage from A2 to IN1. 120AC should appear when the start button is pressed. If not, check the button contact. 

The inputs of soft-starts (and VFDs) are usually very low current. Unbelievable as it sounds, basic standard pushbutton contact blocks (and relays as well) cannot pass this low current. You might heed to get low current contact blocks. This is especially true if the soft-start replaced some sort of mechanical starter. In this case, the lower current of the soft-start won't be able to 'burn through' the oxidation on the contacts. 

Also, make sure the soft-start is looking for external 120AC control voltage and not 24DC.

Rob


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## Dfresh64 (Sep 10, 2011)

I think ur on to something with the start and stop buttons. I will check them (checking voltage on terminals) thanks for the help i will post once I try again.


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## Dfresh64 (Sep 10, 2011)

Update
Everything was wired correctly. 

The dip switches was the problem. Had to redo the switches . 
Thanks again for the reply


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## micromind (Aug 11, 2007)

It's cool that you got it to work. 

Often, especially with anything electronic, it's just one minor thing that stops the entire process. 

And even though we've looked at it several times, we still miss it.


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## Dfresh64 (Sep 10, 2011)

The project was a new grain elevator install. Had several trucks wanting to unload there corn. Then run through a dryer . I had to go through the dip switches 2 more time with a tech on the phone. Got it all working everyone had smiles !! 
Thanks for the help!


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