Modernization of an elevator traction machine

In Chicago we have some very old buildings and aging elevator equipment.  When working on a traction modernization we always take a look at the traction machine and figure out if the machine needs to be changed.  There are several items you in consideration replacing the machine.  I am by far not an expert on elevator traction machines but here are a few things I have learned.

Machine wear – This is a very important item to look at.  Is the existing machine in good condition?

Internal machine wear – You need to look at the machine to see if has wear on the gears.  Wear or uneven wear is typically indicative of lack of maintenance, bad installation or high usage.  I recently ran into a building that the gears had to be changed because the OEM had this machine on an “as needed” maintenance visit, which meant not very often, they ended up having to pull the gears out to have them replaced because the gear oil was very low.

Sheave wear – Most sheaves can be recreated by a machine shop.  We have used Titan Machine in New York for fabricating some sheaves that are out of production and they have done a great job.  There is a point where the cost for repair/recreation of sheaves exceeds the cost of new machine.  Once your drive sheave wears you begin to wear your cables and your lifespan on each cable typically is cut down by 50% each recable.  Again, if you are not watching this on maintenance you will have early wear and you will be chasing your tail to change cables to not wear your sheave more and to change your sheave not to wear your cables.

Logistics of changing an existing machine – 90% of elevator machines are located in a penthouse on top of the building.  This creates a challenge how to get a new machine into the machine room.  Some machine rooms have scuttle holes, some do not.  Some machine rooms have room to hoist, some do not.  One item you have to look at is how bad in the machine versus the cost to remove a building wall, ceiling, floor to get a new machine in.  We had a building that required a 3600lb machine to match the drops of the existing machine.  The issue was there was no pick points and 2 flights of stairs, no easy way to get the new machine up and the old machine down.  We ended up using a smaller machine with blocking[to get the correct rope drop].  This is not a high traffic or high-speed elevator so it wasn’t a huge concern about using a smaller sheave.  We recently had a building the should have had the machine replaced but since it was mounted in the attic of a historic building with slanted roofs we opted to retain the machine and change seals. Again this elevator was not a high traffic or high-speed elevator so it will hold up for a long period of time.

[This machine was on a 4' platform and has a slanted 100 year old roof making the replacement difficult, the building opted to keep the machine]

[A new machine going up to replace a 1960's Otis]

Future reaction points – This is the most important part of the equation.  Buildings are built with machine beams for the elevator that is originally installed.  At times, a new machine has different reactions which will require larger machine beams or a different layout.  This can create a significant problem if it isn’t paid attention to.  The problem being the structural integrity of the building.  If you are not knowledgeable of structural support I would recommend having a structural engineer complete the calculations prior to installation or recommending replacement.

Accessibility of parts – You need to understand if someone can supply, fix or fabricate parts if the machine needs component parts replaced.

Motors – Most motors can be replaced or rewound.  Some motors are obscure so an old Montgomery flange mount motor may not be fabricated by a 3^rd party as an AC motor so the machine may need to be replaced if the controller is modernized.

Gears – There are still some machine shops out there that can fabricate gears, but at what cost?

Brakes – There are a few elevator brake providers that can work with any machine.  Again, there are obscure machines that make it nearly impossible to retrofit a new brake.  This is where a machine shop comes in to repair the old brake.

Speed & efficiency/Gearless machines – The “gearless” product is becoming very popular.  Gearless motors are smaller and can give you better electrical efficiency and can go faster than a geared machine.  Gearless motors also can have a shorter life than a typical geared traction motor.  The precious metals used for most gearless motors are created in China and also create a large amount of undesirable waste with their creation.

What I did not touch on is the cost of replacing a machine during an elevator modernization which often is the largest driver of if it is replaced or not.  The machine replacement is often the largest expense of the elevator modernization project.

As always feel free to contact us at www.colleyelevator.com, email Craigz@colleyelevator.com or call 630-766-7230.