York Ymc2 Chillers Shutdown Shortly After Scheduled Start Time… Tripped Main.. No Display VFD 

I know, I was expecting to find one grounded. Better the pump motor than a tower motor 🫡

It's surprisingly common, after it blows the arc usually breaks the short, but its so close to being grounded as soon as you apply voltage again it arcs again, as you saw after the megger showed 0Mohm at almost 0 volts, the fault would have showed up right away with a megger vs a standard ohmmeter

@@Byron88yeah. That’s why I don’t like using a standard meter when checking for grounded motor

I hear you 👍 Thanks for watching!

Thanks Shaun 👊

That’s a strong willed wire 😃 Thanks for sharing

Definitely 👍

Agreed

You simply measure voltage before and after contacts? I would not have thought about this.

Measure volt across contacts while energized, Thermal camera will also help determine if excessive heat is being generated in any contacts. 0 drop is 👍

Yep, I heard that too 😃

It’s so hard to put it back in after you let it out too… 😅

Expensive too

Oh yeah, nothing like some bbq first thing in the morning. At least the apprentice got to see his first motor smoke release 😁Thanks Jason 👍

😃

Thanks 👍

There’s only 1 chilled water pump on this chiller plant, yes chiller 1 receives the warmer return water from the loop then passes through chiller 2 . Thanks for the question 👍

😎

Appreciate it!

Thanks for watching!

Thanks 👍

Thanks for Watching!

Thanks!

Thanks for the suggestion 👍

I think the issue is simply the peak fault current, which every breaker in series will see simultaneously. A sudden hard fault will have a high enough current to trip upstream breakers. In some applications, some series resistance or inductance is required to limit fault currents to manageable levels - breakers are only rated to break a certain fault current.

The main breaker should be programmed to prevent this, I would have a good electrician check the calculations and programming.

Yes, motor shorted to ground. Thanks for the question. Part 2 is possible 👍

👍

The pump was removed to replace bearings and seals

Somewhere between $4k-$5k depending on availability , I don’t do the purchasing though. Thanks 👍

Sold 👍🤣

There are disconnects 👍

Try watching the whole video.....

It’s more likely the initial short to ground cleared and when power applied it arced to ground again. Thanks for commenting

@@subcoolHVAC oh I wasn't referring to the cause nor am I implying it was overlooked/missed. Just saying you skip teaching a crucial step when checking for shorts to ground. Should always test first from ground to ground then test your lines/loads. If you just take your probe to a ground then use the other and start looking for shorts you assume to know that your grounded probe has proper contact.

Thanks for watching