# MCC startup failure light?



## micromind (Aug 11, 2007)

That's almost certainly a 2 speed motor that is presently running in slow speed. 

Note the 'run slow' pushbutton below it. That's the slow speed start button. 

High speed is on the left side.

Rob


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## glen1971 (Oct 10, 2012)

Micro - I believe the OP is wondering about the amber lamp below the WARNING label. 

I think it must be a monitor of some kind. A look or a pic of the inside of the cubicle would confirm it. Why not open it while it is running, with your PPE on of course? That's what the black screw above and right of the main disconnect handle is for..


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## frenchelectrican (Mar 15, 2007)

One possiblty maybe a ground fault warning light if this system is on floating delta that is one way it possible they add a warning light.

somecase there is other warning device like viberation switch if get too much viberation it will shut down. that part I am aware on larger fan or blowers some do have that escpally exhaust fans thru the roof models.


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## micromind (Aug 11, 2007)

Lol....I figured it was the reset button for the starter O/Ls........

It could be an indicator that the O/Ls have tripped.


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## Big John (May 23, 2010)

frenchelectrican said:


> One possiblty maybe a ground fault warning light if this system is on floating delta that is one way it possible they add a warning light....


 Good thinking, that seems likely.

But I wonder if these are on multiple motors? They would all light up at the same time in the event of any ground fault.


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## glen1971 (Oct 10, 2012)

Big John said:


> Good thinking, that seems likely.
> 
> But I wonder if these are on multiple motors? They would all light up at the same time in the event of any ground fault.


And if it was for a system ground fault, isolating this motor at the breaker would disable the detection system.


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## gnuuser (Jan 13, 2013)

typically these are wired into current monitoring devices such as the vfd and the alarm controlled by a plc.
most likely it was put in after the panel was designed and they didn't document it.
(ive seen this a few times on various equipment)


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## QMED (Sep 14, 2016)

Yes it is on a an ungrounded delta system, it has a separate ground detection panel for all systems.

Thanks guys I will look into it(literally) when I can, no pressing need for me to open it up without de-energizing(don't want anybody getting angry over ventilation lol) I just like to know what everything in my area is.


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## QMED (Sep 14, 2016)

Big John said:


> Good thinking, that seems likely.
> 
> But I wonder if these are on multiple motors? They would all light up at the same time in the event of any ground fault.


All the ventilation controllers of which this is an example have them. I believe they're all vane axial, when I find out what it is I will follow up on my post.


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## frenchelectrican (Mar 15, 2007)

QMED said:


> All the ventilation controllers of which this is an example have them. I believe they're all vane axial, when I find out what it is I will follow up on my post.


Please do post us the details on this so we will know more about that system.


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## QMED (Sep 14, 2016)

*resolution*





































True to my word, looks like if the light ever goes off it will be oh so easy to troubleshoot :laughing:


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## mitch65 (Mar 26, 2015)

This on a ship, in a port? I'd imagine there is a lot of exposure to moist salty air.


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## QMED (Sep 14, 2016)

mitch65 said:


> This on a ship, in a port? I'd imagine there is a lot of exposure to moist salty air.


Ship, supposedly they have some "vapor corrosion inhibitor installed on all the MCC's.


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## JRaef (Mar 23, 2009)

Yeah, those are continuous insulation resistance testing systems. Whenever the motor starter is open (Off), it pulses a voltage through the windings and looks at the return, then if the insulation begins to leak to ground, the return voltage drops and this unit alarms. Some people swear by them, other people equate them to being "idiot lights" because by the time the light goes off, it's already too late. The better program is to have a periodic insulation test as part of a Preventative Maintenance program so that you can keep track of trends and anticipate a failure before it happens. Having these monitors gives people a false sense of security in that they forgo the PM testing, but the only thing these things do is let you know WHY your motor is not working.


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## QMED (Sep 14, 2016)

JRaef said:


> Yeah, those are continuous insulation resistance testing systems. Whenever the motor starter is open (Off), it pulses a voltage through the windings and looks at the return, then if the insulation begins to leak to ground, the return voltage drops and this unit alarms. Some people swear by them, other people equate them to being "idiot lights" because by the time the light goes off, it's already too late. The better program is to have a periodic insulation test as part of a Preventative Maintenance program so that you can keep track of trends and anticipate a failure before it happens. Having these monitors gives people a false sense of security in that they forgo the PM testing, but the only thing these things do is let you know WHY your motor is not working.


Haha yes agreed but much too advanced for my current workplace...why do preventative maintenance when you can just run around like a chicken with your head cut off when it breaks!?! :jester::laughing:


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## MechanicalDVR (Dec 29, 2007)

QMED said:


> Ship, supposedly they have some "vapor corrosion inhibitor installed on all the MCC's.


Typically small heaters with mini 4" circulation fans.


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## JRaef (Mar 23, 2009)

QMED said:


> Haha yes agreed but much too advanced for my current workplace...why do preventative maintenance when you can just run around like a chicken with your head cut off when it breaks!?! :jester::laughing:


Hey, common now, that's the only exercise I get!


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## QMED (Sep 14, 2016)

JRaef said:


> Hey, common now, that's the only exercise I get!


HAHA case in point it would be asking to much to replace a nema frame 143T with another 143T! Just replace it with a 145T and drill new holes Absolutely no good reason to replace in kind! Maybe we could just order new bearings for a few dollars? LOL nope! Get the mag drill and the tapping kit :roll eyes:


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## dronai (Apr 11, 2011)

How long have you been on this job ?


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