# How far can you push old gear?



## paulengr (Oct 8, 2017)

4160 V 400 A transformer feeder. 40 year old Limitamp: one of 3 we had to deal with. One needed contacts cleaned and adjusting. One had a bad PT.


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## joe-nwt (Mar 28, 2019)

That'll buff right out.


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## Majewski (Jan 8, 2016)

Like the song says, push it push it, push it real good!


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## Apelectric (Dec 6, 2017)

Depends on the maintenance performed, the environment the gear is in, how often it was exercised, how often it was cleaned and how well it was originally built. 

On the 4160v side we have 50 year old gear that's built like a brick **** house that is indoors that I would feel comfortable with using forever. We also have 25 - 30 year old gear that is outside and has had salt and snow piled up against it every storm that I could push my hand through the rusted out door and grab the buss. 

The mounting brackets and hardware scare me the most as long as the switch has been exercised. If the switch hasn't been exercised, then I don't like the feeling that the switch has welded itself shut and I'm the guy breaking the weld. After that dust, moisture and anything that would cause it to track and flash over. Also don't like switches that have the ground buss above the feed, we had one rust out and fall onto the live feed and it shot off like a Roman candle for a long time. (The breaker trip coil burnt up trying to trip the breaker so it kept feeding into the fault, an example of why if a switch or breaker hasn't been exercised in a while I'm not thrilled about being the one to open it)


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## Slay301 (Apr 23, 2018)

As long as you don’t touch it or think about turning it off or look at it wrong it should work forever


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## backstay (Feb 3, 2011)

Apelectric said:


> Depends on the maintenance performed, the environment the gear is in, how often it was exercised, how often it was cleaned and how well it was originally built.
> 
> On the 4160v side we have 50 year old gear that's built like a brick **** house that is indoors that I would feel comfortable with using forever. We also have 25 - 30 year old gear that is outside and has had salt and snow piled up against it every storm that I could push my hand through the rusted out door and grab the buss.
> 
> The mounting brackets and hardware scare me the most as long as the switch has been exercised. If the switch hasn't been exercised, then I don't like the feeling that the switch has welded itself shut and I'm the guy breaking the weld. After that dust, moisture and anything that would cause it to track and flash over. Also don't like switches that have the ground buss above the feed, we had one rust out and fall onto the live feed and it shot off like a Roman candle for a long time. (The breaker trip coil burnt up trying to trip the breaker so it kept feeding into the fault, an example of why if a switch or breaker hasn't been exercised in a while I'm not thrilled about being the one to open it)


I agree, most of the 6600 volt gear in the mill was older than me. But very well kept. It’s still there twenty years later.


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## SWDweller (Dec 9, 2020)

I worked for a place where there were two 1940's Allis Chalmers 4160 breakers (5) each side.
Management decided since we rarely ( like twice a year) that known problems would be left alone. We had 3 breakers on one side that would not come out of their cells. They would move enough to disconnect. I felt that the problems should be discovered and fixed. My boss a management dweeb agreed. Because of the issues a new policy was created and we had to dress in a 40 cal suit when racking the breakers in or out.
I have seen some older GE breakers that I am sure as long as they were not operated a lot they would last into the next Millennia. Contacts were clean and showed very little wear.
It really depends on the fault current available and the equipment's use and need.


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## mburtis (Sep 1, 2018)

Having never been around medium voltage gear, what am I looking at? Is there a breaker or other piece of equipment that slides in and connects to what's left of those crusty clips, essentially like an MCC bucket?


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## Slay301 (Apr 23, 2018)

mburtis said:


> Having never been around medium voltage gear, what am I looking at? Is there a breaker or other piece of equipment that slides in and connects to what's left of those crusty clips, essentially like an MCC bucket?


See the tracks at the bottom? Theres
Multiple types the tracks indicate that this is a bucket style breaker that is on wheels and it stabs into those clips. The bucket is on wheels and it and rolls in those tracks. This is where the term racking in comes from. They also have fuses that work at this voltage that are probably 2-3 feet long and a 1000-2000$ a piece:


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## paulengr (Oct 8, 2017)

Slay301 said:


> See the tracks at the bottom? Theres
> Multiple types the tracks indicate that this is a bucket style breaker that is on wheels and it stabs into those clips. The bucket is on wheels and it and rolls in those tracks. This is where the term racking in comes from. They also have fuses that work at this voltage that are probably 2-3 feet long and a 1000-2000$ a piece:


Correct partly. It’s a little hard to explain what these are. They are called transformer feeders. This is a special starter. But instead of driving a motor it’s driving a transformer. This makes it essentially an electrically operated fused disconnect. The fuses are E rated instead of R rated (a double barrel fuse rated 600E). Often they are latching contactors so you have to energize both to close and open. The overload is replaced with more of an overcurrent relay with a normal feeder style trip curve. In 600 V you would see just a normal breaker with a shunt trip and electrical operator to close. You see transformer feeders in medium voltage because they are cheaper and give you fuse-grade AIC.

The clips are the load side (output) where the bus bars on the starter truck slide into. There are three in front for the PTs and three in back for the load (one with a scorched insulator that is disintegrating). The line side are behind shutters on the wall above these. Limitamp starters add weird. They either angle up into the primary stabs at like a 30-45 degree angle or they start out at about 20-25 degrees then Rick down to engage. The starter is hinged in the middle. You can just open it right up to access the main contacts, arc horns, and arc chutes unlike other brands where getting to the guts involves removing the top half with the arc chutes. Vacuum bottle versions of course don’t have all that garbage.


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## SWDweller (Dec 9, 2020)

I call the burned parts the stabs. A lot of those parts are available. However you MUST remove all of the carbon before you attempt the re-connection. Other wise your looking at a flash over. 
NEVER EVER close these old dogs into a load. A transformer with the secondaries off ok.

Once the carbon is off, using your cleaner of choice. I liked Cable Clean but now days it is frowned on by a lot of places. Unbolt the parts test or replace the insulators and bolt up the new parts, easy peasy. 
If you do not have the time or need a certifiable repair. Try the Eaton ACE offices. They are scattered all over the US. They have the equipment, testers and ability to return the breaker to its former glory. Manufacture of the breaker is irrelevant to them. I used to work for Eaton so other MFG's may have similar offices as well. Just unknown to me. The office in Southern California saved my butt many times. You really must update the tripping mechinims of these old dogs. Current tec can be brought into the mix, by adding ct's and pt's.

The medium voltage market is different then the low voltage market. Parts streams come from a lot of different places. Like an air plane motor age is not all that important condition is.


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## VELOCI3 (Aug 15, 2019)

At one of the ATT buildings we have 5 services. 10 4000 amp 208V ITE truck mounted breakers (5 utility and 5 EM). They were modernized twice since 1952 plus the gear bus was reinforced. Bulldog switchgear and bus duct. They work but need a lot of TLC for the monthly generator runs. 


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