Miprom 21 A/C in overhead

I have a 4 car low rise geared group, very often the cars end up on the top final with a “38 nts” fault. We have replaced the entire brake circuit components and i recently slowed the cars down 75fpm with no good results. The very odd thing is that nobody ever has been entrapped in cars, this has been an issue for about 6 months on all of the cars. Any ideas fellas?

Traction or Balance Problem? Try putting about 400 lbs of weight on car top and see if it goes away. If it does you have a balance problem. That was very common.

Another cause was the ETS Switch interfered with an NTS Stop. Try moving the ETS a coulpe of inches closer to the floor. To see if you can make a good NTS stop. Run a buffer test without jumpering out the NTS Switches. If the car doesn't stop correctly, you either have the above problem, or the NTS Switch voltages are not adjusted correctly.

There is a software fix for this. Call Cetek and ask for target chasing software fix. This is only on AC drives, usually happens in the middle of the night, never anyone trapped. Car dispatches itself to some non-existent floor.

Of coarse like with any Miprom 21 going in the overhead with 38 errors you should do an NTS and ETS test to make sure they both work correctly. But if there is no problem there, call Cetek!

We had this for years on a DC mod job. Same thing, cars in the overhead or sometimes the pit and never an entrapment, new software did the trick.

You can see that the car drives itself into the final limits if you check the 3 digit mode/region/direction capture on service tool. That software fix was sent out to MOST of the jobs by now, it was 15ish years ago i think when that came about. Cetek is gonna rape you for it if you're a competitor of Kone. Take vaseline

Heard about a balance issue, as i think Montgomery had those at 40% from factory, but i swear that every time i took a call on the mysterious final, the direction was driving towards the terminal.

It could be a ton of different things really. Brake panel and M contactor aux's are a common start. Could be a pilot relay in drive, a sloppy encoder, a door lock bounce, etc. Gotta have tool to watch IO's to figure out

Start with replacing the relays for slowdown switches on NTS board with bifurcated ones. They are operating on 1 to 8volts. Gotta adjust those pots very carefully. They usually don't wander that bad after setup. Did you set the MSU 8volt?

Start with the 400 lbs on car top.. it's a hell of a lot cheaper then the post above this.

Thanks fellas, I’m going to try the weight issue and get a price from for software. There isn’t the terminal switch board on these with the pots to adjust. I have replaced every relay in brake circuit along with relays involved in ets circuits along with main board behind relay board that has the smaller micro relays on it.

Adding weight to the car top may sound like a quick fix. However as a QEI Inspector, I would write this up as a deficiency, and shut the car down. You are changing the the capacity of the elevator.

I tend to agree with John Jay, never liked the idea. Just get some test weights out and check the counterweighting. It should probably be 40%. If it’s balanced correctly, just sell the software to the customer.