[Mobius87]

I've got a senior citizen 4 story condo complex that I do service work for, with an elevator that has been causing me troubles for the past year.

6pm on Thanksgiving (Canada) 2021 I received an emergency call that the elevator at this building had stopped working. I was closer than the elevator guy, so I went there to see if I could get them out. I found that the breaker feeding the elevator had tripped. Everything checked out, so I reset the breaker and all was well. I could not find anything that would cause the breaker to trip nor could I replicate the issue, and I assumed that the breaker itself might be the problem. I didn't have a replacement (NA Stabloc 3P 100A), but I did have two 2P 125's that I made work for the weekend until I could get a replacement.

No new replacements were available, but I did find one that was used and in good condition. I installed that 'new' breaker and it's been working without fail until yesterday when I received another call that the breaker had tripped on six different occasions over the previous 2 days.

This time I was able to replicate the issue. I would run the elevator to the top floor twice in quick succession. The second time, just as the elevator would near the 4th floor, the breaker would trip. I repeated the test and got the same results.

I checked every wiring connection in the elevator control box, disconnect, and panel. I meggered the motor and the wiring and found no issues. I IR scanned the breaker, contactors, and disconnect for hot spots and saw nothing abnormal. The panel bus shows no signs of overheating or arcing.

I hooked up the power meter and ran the elevator a few times to see if anything would show up there. The voltages are consistent (212V idle, 210V under load), and the current values are close as well. There's a short inrush spike at startup (131A) which settles to 64A for the first 2 floors. It drops to 58A at about the 3rd floor, and stays there until it reaches the top. On the second run everything is identical, except that the breaker trips right before the elevator reaches the top (58A). No spike in current or dip in voltage. The breaker stays cool to the touch, and the IR doesn't show any abnormal heat either.

Not sure what else to tell them other than I need to find another breaker. I swapped out the 100A for the jury rigged 125's again and ran the elevator 4 times up and down without fail.

Any other ideas?

 

[MikeFL]

Testing still on that old 100A breaker?

Worn out breaker. How old is the building?

 

[Mobius87]

Testing still on that old 100A breaker?

Worn out breaker. How old is the building?

Original breaker was there since the 80's. It got replaced with a second hand breaker a year ago, which appears to have failed in a similar way.

 

[MikeFL]

Do they have a freight elevator or is this how they move pianos?

Did you have opportunity to measure current with the elevator at max load/ occupancy?

 

[wcord]

Large (100, 125 and 150) Federal breakers are notorious for not being able to handle loads, once they have tripped a few times.
My rule of thumb was to replace, once the breaker has tripped the third time.

On a side note, I think you are opening yourself up to a liability problem if you are troubleshooting the elevator controls. .

 

[micromind]

If there's room, set either a fused disconnect or a breaker enclosure (of a more reliable brand) next to the panel. Feed it from the main lugs and have it feed the elevator.

 

[backstay]

Large (100, 125 and 150) Federal breakers are notorious for not being able to handle loads, once they have tripped a few times.
My rule of thumb was to replace, once the breaker has tripped the third time.

On a side note, I think you are opening yourself up to a liability problem if you are troubleshooting the elevator controls. .

Can’t electricians work on elevators up north?

 

[macmikeman]

It has happened to me, called about elevator tripping constantly at a building I was always getting calls from. I told the maintenance manager us civilians are not supposed to be working in the elevator machine room (unless requested by elevator company) , but it was Friday afternoon and the elevator guys were all gone home. So I came- I changed out the breaker and that solved the problem, it hasn't happened again for better than a year now.

 

[Almost Retired]

elevator is about 40 yrs old, unless its been replaced.. the car and the guides will have significant wear
if the elevator is able to move around sideways in the shaft (loose, worn out fit in the shaft way), it may be missing or hitting a limit switch or some such control
take a ride in it and pay attention to bumps or bangs in the ride
at any rate i would get out of that situation and call in some experienced elevator guys and leave it to them

 

[eddy current]

Can’t electricians work on elevators up north?

Only the power to them can be done by electricians. Elevator mechanics do the rest.

I had a call where there was no power to the elevator. Found 2 blown 90 amp fuses. Fuses do not blow without reason very often so I expected something wrong with the elevator equipment. I Supplied 3 new fuses but told them I won’t energize my side unless I could first disconnect the elevator equipment (the load) but it is their equipment so they need to do it.
elevator guy was coming later and told them all he needed was the fuses and I could leave.

Couple hours later they call and say the elevator guy energized, the motor blew up and the elevator guy was trying to blame me. Good thing I did all the work with their maintenance watching/ helping and I had documentation of what I did.

 

[SWDweller]

Down here in the desert we do not use breakers on elevators. Fused disconnects only.

I have never trusted IR anything unless in was working when the event happened. To many ways to fool it for my taste.

I agree about the old breakers, especially that MFG. Time to find a new breaker and install it at the very least.

As an electrician I supply power to the elevator everything else is up to the elevator contractor employees. The licensing and insurance is higher for them. The bonding starts out at 40 million I believe. Once in my career my licence needed a 5 million dollar bond.

 

[backstay]

Only the power to them can be done by electricians. Elevator mechanics do the rest.

I had a call where there was no power to the elevator. Found 2 blown 90 amp fuses. Fuses do not blow without reason very often so I expected something wrong with the elevator equipment. I Supplied 3 new fuses but told them I won’t energize my side unless I could first disconnect the elevator equipment (the load) but it is their equipment so they need to do it.
elevator guy was coming later and told them all he needed was the fuses and I could leave.

Couple hours later they call and say the elevator guy energized, the motor blew up and the elevator guy was trying to blame me. Good thing I did all the work with their maintenance watching/ helping and I had documentation of what I did.

There were 9 or 10 elevators in the paper mill. I got to work on them all. There was even a man lift. That thing was the best people moving machine!

 

[wcord]

Can’t electricians work on elevators up north?

We bring power to a disconnect and then the elevator installers take it from there.
Elevator mechanic is a licensed trade and afaik are the only ones allowed to install/maintain elevators.

 

[Mobius87]

The elevator company has been involved with this as well. They were called first when it starting tripping again recently and couldn't find anything wrong either. Must be another failed breaker.

The condo board is open to replacing the house panels (which feed the elevator), but the way things are it will likely be a year or more until I could get some 200A 3 phase panels around here. Looks like it will have to be plan 'B' like @micromind suggested.

 

[Mobius87]

Do they have a freight elevator or is this how they move pianos?

Did you have opportunity to measure current with the elevator at max load/ occupancy?

Only elevator in the building. I didn't try to run it at max capacity as we were able to make it trip with no one in it.

 

[Sbuklad]

Ex elevator mechanic here. 12+ years in the trade before withdrawing from the union. My $.02 is what has been said before. You need to ride it throughout travel. Stand in the center of the elevator and shift you weight on your feet side to side while traveling if like mentioned above there is slop in the Guides/Roller setup you will feel it. Also you have to consider if the main rope sheaves have has the bearing blocks greased. The condition of the ropes. Some roped elevators have a rope clamp brake that will trip and clamp down fast to the ropes is this dragging. What is the condition of the rails? The building compresses over time and will cause the rails to not be true any longer sometimes even causing compression bulge where the joints are. When it was installed the rail should be true / plumb to within 1/64" both directions off the blade. I had experience where elevators were loaded violently at a mid floor and the impact of the load on the elevator knocked the rail supports out of alignment when the cab pushed back from the impact.

I also agree not to use a circuit breaker. It would be much better to use the proper fuse disconnect.

Have the motor windings been tested? - Mechanically secure connections in the motor wiring box? . I can't remember if that was mentioned.

Max capacity I would not think is so important since you have a counterweight that is stacked for 125% of full load you are moving up and down with an empty cab. That said your weight stack is at the bottom (pit) when your elevator is at the top floor. slowing and stopping to arrive at the top floor will ramp current also when you depart the top floor you are pulling that stack up as the cab travels down so high current to get things moving as you depart the floor.

Another thing to consider is the connections of the load center the CB is mounted in. As well as the connections that feed the load center.
Where I work now we will get a CB trip in a machine cabinet that every now and then is caused by a poor connection with the buss bar connection overhead not the machine itself. sometimes the problem is upstream not downstream.

As I realize I am getting long winded I also realize that not having elevator experience I should clarify above rope = Wire Rope elevator guys do not use cable : )

Happy hunting for your gremlin

 

[MikeFL]

Ex elevator mechanic here...

Max capacity I would not think is so important since you have a counterweight that is stacked for 125% of full load you are moving up and down with an empty cab. ...

Happy hunting for your gremlin

So max current draw on that motor is when an empty cab is descending.
Interesting.

In Physics class that counterweight never existed! (PHY101)

 

[MHElectric]

In most new construction around here, the electricians only supply power and a fused disconnect in the elevator room. EVERYTHING past this point is on an elevator company.

 

[micromind]

In most new construction around here, the electricians only supply power and a fused disconnect in the elevator room. EVERYTHING past this point is on an elevator company.

Same here except we also supply and install the lights, one 120 GFI and if there's a pit we install a GFI, light and a single receptacle for the sump pump.

 

[MHElectric]

Same here except we also supply and install the lights, one 120 GFI and if there's a pit we install a GFI, light and a single receptacle for the sump pump.

I forgot about all that stuff in the pit. Your right. It’s been a while since I’ve been in new construction.