Remove and replace Kone MX20 flat motor

I've got a job coming up, where we will remove and replace a Kone MX20 flat motor. As we know, it's bolted to the top rail section, and the hoist ropes are just behind the rail.

There seems to be a couple of ways it could be done-

I was thinking of landing the cwt, and hanging the car. That pin on the crosshead looks pretty frail, for landing the car on- Any known issues with these?

Then unbolt the fish plate for the top rail section, rig and swing the whole motor/rail assy onto the crosshead, cables and all, where it could then be dissasembled and wrestled with.

Any suggestions?

I think the pin on the crosshead your referring to is where you would engage the bracket on the rail when working on the brakes in case of unintended movement. Look in the overhead for the I beam that was used during construction, it's usually left in place. That would be ideal for hanging the car. The car shouldn't weigh that much. The cabs are garbage just like the rest of the equipment.

Ok, so that's not intended to hold the car for heavy repairs- just an additional safety while servicing...I had no idea, thanks!

I only use the locking bar when checking the holding pressure of a single brake too make sure a single brake will hold the car if one brake fails ,I put the car on the safety's then sling it put a Chicago hitch on the counter weight ropes pick the counter weight for rope slack on drive sheave block up the counter weight or hang it and if the hoisting beam is still in place use chain fall and trolley to pick the motor and swing it out from behind the rail if your over two hundred pounds you'll cave the car top in so I wouldn't put that sort of weight on the car if at all possible maybe this helps just wondering why is the motor being pulled ?.

Wow, fate, thanks!
Do you pull the hoist ropes up and over the motor, so the motor will swing under the ropes, then out from behind the rail? I don't suppose you swing the motor out with the ropes still on the driver.....so you must be leaving them behind, right? Like, tied up with rope hitches, to keep them clear of the motor, and keep them in order, and tight in the undercar sheave grooves?

This particular motor got wet, due to direct water entry into the shaft. There is a design/build defect in the way the shaft was constructed, that alloed a lot of water to be sucked in by the motors' cooling fan, which blew it right into the motor windings. This happened almost a year ago, while the lawyers were looking into it, and even now after all this time, the motor still reads direct short to ground, all three phases, even with all field wires disconnected, right at the motor connection box. Definitely afu.

When I get this figured out, I'm gonna post the answer on elevator forums worldwide. Pics, video, text, the whole nine yards.

Thnkx

I think I'm gonna un-rope it. That's one way to get that "button" out of the shaft!

The ropes dont need to be removed. You take them out of the motor by removing the iron cross, that holds them captive. We loosened the iron cross center bolt, that went from the rear of the stator, out to the iron cross, where it threads into a threaded hole in the cross. Then we could rock the iron cross enough to get the ropes free. Only our cross was painted stuck to the stator housing, so we had to tap it and pry it back and forth to get it loose. It also has locating dowels, so the cross has to move straight back to slide off the dowels. We actually took it off the end of the sheave shaft. The cross has a machined mesa, that tucks into the sheave shaft bearing inner race, and this helps support the sheave shaft. The ropes were easy to remove, and the iron cross was easy to get back on. I've got the motor up off the pedestal, ready to go out the entrance. Next I need a cart that can hold 1,760 pounds!

Here is an expanded version of the last post. I hope it will prove beneficial for the elevator industry at large.

The ropes dont need to be removed.

The MX20 motor has 3 major componenets-

1. The first component is a big iron bowl, or stator housing, which faces or is right up against the hoistway wall. There is a separate circular iron core, bolted to the housing from the backside, onto which the copper windings are wound. The housing has a shaft at its center, that the load bearings go onto. So the stator housing also becomes the sheave shaft.

2. The second outer component is an iron cross of sorts, on the opposite side from the stator housing, right up against the back of the rail, clamping the rotor within the outer halves of the machine. There is a long bolt, 14mm allen head, that runs through the stator, through the sheave shaft, and threads into the iron cross. The cross also has 10 allen head bolts on its periphery, threaded into the stator housing.

3. The third component is the rotor, sandwiched in between the stator housing and the iron cross, which also comprises the drive sheave, in the same casting. The rotor slides onto the sheave shaft bearings.

These three basic components are bolted together, and sit in a pedestal at the bottom end. The pedestal is bolted to the back side of the rail. The top of the motor is stabilized in a rubber isolator, and this isolator is bolted to the back side of the rail.

The rotor has what is, (I think), neodymium iron boron magnets. The advantage of permanent magnets is that there is no power losses from inducing current flow in copper loops, such as on an induction motor, where the oscillating stator field must induce current flow in the rotor hoops, (generating their own opposing magnetic field), to get the rotor to react with the stators' rotating magnetic field. Permanent magnets don't need extra energy to be expended to give them a field of their own, that's where the power savings come from. Nicolai Tesla did not have these at his disposal, when he invented the squirrel-cage induction motor. Permanenent Magnet Synchronous Motors (PMSM) use much less power to produce the same torque, compared to common industrial induction motors. This makes Kone look eco-friendly, and consultants then get on the bandwagon, and reccomend this monospace crap to unsuspecting building owners, and property developers.

The PMSM is the only good thing I have to say about Kone. Everything else is, well, I could go on, but this post is about removing the PMSM motor, and time does not permit me to go into further sad details about Kones' monospace product. if anyone wants to know whether they should choose this stuff for their project, a few minutes searching on the net will yield all they need to know.

Back to the motor removal.

At first glance, it looks like the hoist ropes are held captive by the motor. During construction, they thread the hoist ropes through the machine, (no motor dissasembly required!). But to remove the motor after it has bneen roped up, the hoist ropes are now "holding" the motor behind the rail. You either have to take the ropes back out of the machine, or you have to partially dissasemble the motor. The latter is the easiest route.

You take them out of the motor by removing the iron cross, that holds them captive. After disconnecting the 3 phase, tach, resolver, cooling fan, emer brake release cable, etc, you rig the top of the motor to steady it, then unbolt the top motor stabilizer from the rail. We loosened in advance the iron cross center bolt, that went from the rear of the stator, where teh head of the bolt is, then it goes out to the iron cross, where it tightens into a threaded hole in the cross. Then by loosening the rigging, we leaned the motor over towards the wall, so the cross has room to wiggle off of the stator housing.

Then we could rock the iron cross out away from the machine, just enough to get the ropes free. Only our cross was painted stuck to the stator housing, so we had to tap it and pry it back and forth to get it loose. It also has locating dowels down at the bottom, so the cross has to move straight back to slide off the dowels. We actually took it off the end of the sheave shaft. The cross has a round machined mesa, about the size of a hockey puck, that tucks into the sheave shaft or bearing inner race, and this helps support the sheave shaft.

As the iron cross is rocked horizontally from side to side, it reveals enough space between it and the stator housing, to where each rope may be pulled out from behind the cross, and tied up out of the way. This divorces the hoist ropes from the machine, and allows the machine to be removed from the shaft. The iron cross was easy to get back on. I've got the motor up off the pedestal, ready to go out the entrance. Next I need a cart that can hold 1,760 pounds!

We'll see what the local rewinding experts have to say about the feasibility of rewinding the stator. Kone has priced themselves out of practicality, to where alternate sources will be sought. If this turns out well, I'll post it here, and elswhere. This may result in greater attrition, so one wonders if their monospace business model is sustainable.

Here is the motor in question. You can see how the hoist ropes go through the motor. And there is my esteemed associate, Santos.

Vic,
thanks for the elaborated info.

How is the lift now? Running?

Yep, it's been running about a year now.

It had an unrelated problem with a com board, and one of the staff at the police station where it is located smashed a call button. But other than that, it's been running good.

Plus, it seems that the customer has fixed the original problem with water incursion into the shaft, so the issue has been put to bed.

How did you happen to dig up this old thread? Got a motor replacement to do?

Hola compañeros de casualidad alguien podra ayudarme con este problema

Tengo una maquina KONE mx20l de las llamadas monospace que necesita ser embobinada nuevamente ya que sufrio un corto circuito pero lo malo es que intentaron repararla y solo le sacaron el alambre magneto de cobre y no la repararon ahora su estator esta sin embobinar ni datos, y me gustaria saber que datos en el embobinado deve de llevar??
Tengo lo siguiente
Tiene 144 ranuras
lleva 72 grupos de 2 bobinas en media ranura
Conexion YY
seccion de alambre lleva 8 hilos de calibre #20 awg y 1 hilo de calibre #18 awg

Lo que me falta saber es como va conectado el puente??
Segun la placa funciona con 283 volts 24hz a 102 RMP lleva conectado un variador de frecuencia

espero me ayuden saludos desde mexico df

KONE here. About to do this myself. Worked in construction for the past 14yrs. I've put in about 100 of these things and will be replacing the first of four, on a job I did the install on no less.

Just wanted to know a few details. The removal of the iron cross seems like the vast way to preserve the ropes and not have to do a rerope. My biggest concern is the rail. During construction we remove the main guide to install the motor. Did you do the same here or did you swing it out the front?

I know this thread is old, about the age of when I installed the damn things. Just thought I'd see what I could find. The more info, the better.