Goofy Control Circuit

[Johnnybob]

It is a 3 wire system yes, (old GE S/S station). I can physically see the stop make and break contact when I push it in and let it out...same with the start...just doesn't make any sense

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Stuck/burnt aux contacts on the 3 wire seal-in?

 

[Johnnybob]

from the picture, it appears that there are auxiliary relays that are performing the 'hold' function

they are just to the left of the 3-pole contactors at upper center and middle-left side

Just a wild-arsed guess, you understand..........

No, I can see the aux contacts on the side of the GE starters.

 

[Johnnybob]

from the picture, it appears that there are auxiliary relays that are performing the 'hold' function

they are just to the left of the 3-pole contactors at upper center and middle-left side

Just a wild-arsed guess, you understand..........

Those are dashpot (pneumatic) timers. the aux.'s are on theleft hand side of the starters.

 

[Johnnybob]

Does anyone know what the "transormer" looking things are? My guess is an old school soft start...but that being said, I don't have really any experience with them.

I get the holding circuit likely being the problem but looking at this massive setup...just didn't know where to start looking for it

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Line reactors.

 

[kwired]

Is there still a need for reduced voltage starting methods? Around these parts there generally is no need for that until you get over at least 100 HP motors, or if mechanically "soft starting" is desirable - but that is usually done via electronic soft starters that have even greater "ramping control". An autotransformer starting method was primarily for reducing the amount of surge otherwise encountered when starting across the line. Improvement in the supply over the past 40 years may not require this anymore.

Chances are something in the present control scheme is malfunctioning, could be a pushbutton contact, holding contact on a relay/contactor, hung up contact on a transition timer, or intermittent operation of any of those things if it is not consistent in nature.

 

[Johnnybob]

I have basic knowledge of control circuits. I am TERRIBLE at drawing out my own schematics but can follow them pretty well. What do you mean by "interposing relay"?

Right, an interposing relay is any relay used to control different voltage or current drawing devices. A motor starter could be called an interposing relay,(lower, or control, single phase voltage switching 480 (or whatever) three phase, to give an example.

 

[ptonsparky]

Is there still a need for reduced voltage starting methods? Around these parts there generally is no need for that until you get over at least 100 HP motors, or if mechanically "soft starting" is desirable - but that is usually done via electronic soft starters that have even greater "ramping control". An autotransformer starting method was primarily for reducing the amount of surge otherwise encountered when starting across the line. Improvement in the supply over the past 40 years may not require this anymore.

Chances are something in the present control scheme is malfunctioning, could be a pushbutton contact, holding contact on a relay/contactor, hung up contact on a transition timer, or intermittent operation of any of those things if it is not consistent in nature.

Yes, unless.there is.a major reason for maintaining those starters they could be updated and the whole thing cleaned up.

 

[Johnnybob]

Right, an interposing relay is any relay used to control different voltage or current drawing devices. A motor starter could be called an interposing relay,(lower, or control, single phase voltage switching 480 (or whatever) three phase, to give an example.

So this is copied verbatum from my college notes(Thank you, Rod Hedman, Instructor, Advanced PLC Programming and Integration @ Spokane Community College.)
To whit:
"An interposing relay is used to overcome limitations of output modules. Use of Interposing Relays are commonly used when you; exceed the current capability of an output point, do not meet the the minimum current requirements of an output point, use a different voltage that the module cannot control, use a different current than what the module can control (a bit redundant), require electrical isolation between different power sources, or have problems with leakage current in your control circuit."
Whew, that was a mouthful, even for a mouthy guy like me lol!