Troubleshooting UEL Elevator Call and Travel Faults

One UEL installation reportedly lost four 160-frame motors in a year while low-speed travel seemed unusually long; the deciding evidence is motor current and temperature over the low-speed interval, not the symptom alone. Separate that thermal problem from two other reported behaviors: a hall call taking precedence over a registered car call, and a car passing its selected floor at full speed before returning to it. Each points to a different part of the control chain and needs its own test record.

Reported UEL cabinet and documentation variants

A presentation account described regulated and unregulated cabinet options, a freight configuration, and software selection between regulated and unregulated operation. It described two boards: one identified as the MPU, with the remaining circuitry on the other board. Treat these as reported configuration details, not a substitute for identifying the installed cabinet, board revision, software, and wiring diagram.

The same account described an older matrix and output-indicator LEDs connected in parallel with contactor outputs. That arrangement can indicate that the controller is commanding an output; it does not prove that a contactor coil energized, that its contacts closed, or that the motor received the expected power. The distinction matters when the symptom looks like a logic failure but the actual fault is in the output or power path.

A separate documentation complaint named and its CPU board, and reported that an electronic schematic was unavailable and the supplied paper drawing was unreadable. This is a specific reported case, not a property of every UEL. Obtain a legible, model-matched drawing before tracing terminals or replacing parts. Questions about phase monitoring on the power board and a fuse on the brake module were left unresolved in the discussion; verify both against the actual drawing and installed hardware rather than presuming either feature is present.

Diagnostic quantities separating dispatch, motion, and heat

Start with the measured behavior, not a product-family assumption. A call-selection complaint is a sequence-of-events problem. A car that misses a floor is a position and motion-control problem. A hot or failed motor is a thermal-load problem, even if its timing symptom began with the controller.

Observed condition	Deciding quantity or state	Where to read or verify it
Car answers a hall call despite a car call	Order and registration time for both requests, door state, and departure command	Controller diagnostics, call indicators, and a time-stamped observation of the door and motion sequence
Car passes a selected floor at full speed and returns	Actual car position and speed compared with controller position, sensor pulses, slowdown command, and terminal-zone state	Approved controller diagnostics, sensor circuit, and the installation-specific shaft reference
Fault 45 appears at low speed or on inspection	Fault definition for the installed software, operating mode, speed command, and speed feedback	Exact UEL fault table and diagnostic buffer for the installed revision
Low-speed travel runs long or a motor overheats	Low-speed duration, motor current, temperature, load, and duty cycle	Motor and drive nameplates, approved drive diagnostics, and measurements taken during repeatable runs
Output LED is on but the commanded action does not occur	Controller output state versus coil voltage, contactor state, and downstream power	Wiring diagram and qualified electrical measurements at the output stage

The reports do not give numerical current, temperature, pulse-count, or slowdown limits. Read permissible values from the installed motor and drive data and the controller documentation for that revision. Do not create a limit from a symptom description.

Car-call registration and hall-call dispatch timing

The reported example is specific: a passenger enters at floor 24, intends to travel to floor 25, and presses the car-call button before the doors close. A hall call at floor 2 is also registered, and the car reportedly departs to that hall call. The key question is whether the car call was registered inside the controller before the hall-call dispatch decision—not merely whether a button was pressed.

The cited wording for PUBEL clause 6.3.3 was that departure in response to a landing call is permitted no earlier than after door closure if a car command has not been registered. A separate interpretation in the reports says a hall call must not dispatch a car while the doors are open and that a registered car command should prevent the described diversion. Check the full, applicable text and the installed controller specification; the quoted sentence alone does not describe every possible door and registration state.

1. Have qualified elevator personnel arrange a controlled, passenger-free test under the site procedure. Keep protective circuits active; do not bypass a door, brake, or travel protection to reproduce the behavior.
2. Record the initial floor, direction, door state, selected car floor, and hall-call floor. For the reported case, use the described 24-to-25 car command and floor-2 hall call only if those are appropriate test points for the installation.
3. Record when the car button is pressed, when the controller accepts or displays the car call, when the hall call is accepted, when the doors close, and when a motion command occurs. Use controller diagnostics where available; a lamp alone may not establish the controller's registration state.
4. Repeat with the hall call registered before the car call, then with the car call registered before door closure. Compare each event sequence with the full applicable requirement and the configured UEL logic.
5. Run the same test in the actual operating arrangement. A single-car result does not establish behavior in a paired or grouped system, and a group result must not be used to explain a single-car dispatch without matching evidence.

If the controller accepts the car call before closure but dispatches to the hall call anyway, preserve the event record, board identity, and software identification for the manufacturer. Do not mask a reproducible sequence by changing unrelated travel or timing settings.

Full-speed floor passing and return motion

Another report describes the car passing a requested floor at full speed without slowing, entering a zone identified as DVE, then returning to the registered floor. A sensor that fails to count pulses was proposed as a cause, and was mentioned, but the report did not establish that diagnosis. Similar behavior on several replaced elevators makes a shared setup, sensor installation, wiring, or software condition worth comparing; it does not by itself identify which one failed.

Because a failure to slow at the intended floor is a travel-control symptom, stop passenger operation under the site's elevator-service procedure until qualified personnel determine that the motion and protective functions are correct. Preserve the event before resetting the fault if the controller allows it safely.

1. Record the requested floor, actual floor passed, direction, observed speed, controller-indicated position, and the time or position at which slowdown was commanded.
2. Capture sensor pulse or position data and the corresponding slowdown and terminal-zone states using manufacturer-approved diagnostics. Compare controller indication with the installation's physical floor references; do not infer accuracy from a display that depends on the same sensor being tested.
3. Inspect the sensor, its mounting and alignment, supply, connector, and wiring against the approved drawing. Check pulse quality and continuity with suitable instruments and safe access procedures.
4. Compare the event across affected cars. If the same board/software and setup reproduce it, prioritize common configuration and installation checks; if a specific sensor or wiring assembly follows the fault, investigate that component.
5. After correction, verify slowdown and leveling at the affected floors in both directions and operating modes required by the site's commissioning procedure. Record the observed motion and controller indications together.

The return trip to the registered floor is not evidence that the original pass was harmless or that the sensor diagnosis is correct. It is a second motion event that must be explained by the controller's recorded position, sequence, and protection states.

Fault 45 in low-speed and inspection operation

A report associates fault 45 with low-speed travel and inspection operation on modernized hoists, including a Mogilev installation with a 160-frame motor; earlier trouble with Montanari equipment was also mentioned. The number alone does not identify a failed component. Fault tables can vary by product and software, so retrieve the definition from the manual matching the installed UEL board and software revision.

Capture the full fault record before clearing it: operating mode, direction, command speed, feedback speed, position or pulse count, output state, and any preceding fault. Compare normal low-speed runs with inspection runs. If the code appears only in one mode, that narrows the conditions to compare, but it does not prove the mode or hoist caused the fault.

One report says an adjustment described as reducing the number of impulses had no effect and was considered nonfunctional. Do not treat that description as a verified parameter name or keep changing it by trial and error. Identify the actual documented setting, record its value before and after, confirm the controller reads it back, and observe whether the measured pulse or slowdown behavior changes. If the parameter's purpose or units are unclear, obtain the exact revision-specific documentation before editing it.

Low-speed thermal load and repeated motor damage

Motor heating depends on electrical loss, cooling, load, and time. Copper loss increases with current squared, while a prolonged low-speed interval extends the time over which losses accumulate. If the motor relies on a shaft-driven fan, cooling can also decrease at low speed; check the motor's actual cooling arrangement rather than assuming it has that design. The reported long crawl and repeated failures therefore warrant measurements, but they do not prove that the UEL station caused the damage.

The report attributes four failed 160-frame motors over a year to the installation and says the motor maker accepted warranty claims. That makes a motor-side defect a live alternative to controller logic, and the two can coexist. Separate them with correlated measurements:

1. Identify the motor and drive ratings, cooling method, permitted duty, and the supply topology from their nameplates and approved drawings. The source does not state whether measured current is single-phase current, three-phase line current, or per-phase current, so use the actual wiring to select the correct comparison.
2. During a repeatable low-speed run, record actual low-speed duration, current in the applicable conductors, load condition, and motor temperature. Compare each value with the motor and drive limits for that configuration; do not substitute an assumed current or temperature threshold.
3. Compare a healthy and affected run under similar load. High current points toward electrical loading, drive configuration, a mechanical load, or a motor condition; normal current with increasing temperature points toward cooling, duty, or a temperature-measurement issue. These patterns guide checks but do not replace the motor maker's diagnosis.
4. Inspect relevant mechanical and cooling conditions, including brake release, ventilation, and signs of drag, using the approved service procedure. Retain failed-motor test results and claim findings so a motor defect is not incorrectly attributed to the controller.

If low speed is unusually long but the referenced pulse adjustment has no measurable effect, verify the actual slowdown inputs and output sequence before revising settings. If current or temperature reaches the motor's documented limit, stop the test and follow the equipment manufacturer's service instructions.

Output LEDs, brake module, and interface checks

On the reported cabinet, indicator LEDs were wired in parallel with starter outputs. Use them as command-state evidence only. When an LED is on but a contactor does not operate, trace the output, coil supply, and return path; when a contactor operates but the motor response is wrong, continue through the contactor contacts, drive or power stage, and motor circuit. Use the exact wiring diagram and qualified measurement practices.

A discussion comment said the factory specified which contactors to use. Treat that as a reason to check the approved bill of materials and ratings before substituting a preferred part, not as proof that every installed contactor is correct. Another comment raised concern that a failed solid-state key module might not be repairable. Verify the actual module's replaceable-unit policy and obtain the matching spare rather than assuming either board-level repair or whole-module replacement.

The reports also asked whether phase monitoring was on the power board and whether the brake module had a fuse. They do not answer those questions. Confirm those details from the installed unit and legible drawing. A comment described a BUAD-related arrangement as putting three breaker phases in parallel, but gave no circuit nodes or purpose; treat it as a drawing-review question, never as a wiring instruction. Confirm the approved interface schematic before any modification.

Bench, tower, and field validation

Bench, tower, and in-service tests answer different questions. A bench or simulator can repeat event sequences and isolate board logic, but it cannot reproduce every shaft, load, cooling, or traffic condition. A tower test exercises real travel over a controlled route but does not establish long-term behavior in occupied buildings. Field operation provides representative duty and traffic only when it is controlled, documented, and supervised.

Test approach	What it can establish	What it leaves open
Board bench or elevator simulator	Repeatable input order, call registration, output states, and fault capture	Installed sensor geometry, real hoist load, ventilation, and building traffic
Test tower	Travel sequence, slowdown behavior, and motion under controlled conditions	Long-duration service, occupancy patterns, and the range of field installations
Controlled field trial	Actual site duty, temperature trends, call behavior, and recurring faults	General product reliability unless the sample and operating range are broad enough

A contributor proposed a trial of 10–20 elevators over at least a year, covering regulated and unregulated residential and administrative buildings, hospitals, and freight service. That is a proposed validation target from the reports, not a published requirement or proof that such a trial occurred. The same discussion mentioned pairs and groups of four in connection with earlier equipment; verify that the installed UEL supports the specific group configuration before adding it to a test plan. The proposed 1.6 m/s case is likewise relevant only where the actual equipment is rated and configured for that speed.

For a release or site acceptance decision, run repeatable bench and tower cases first, then a controlled field trial covering only installed configurations. Log board and software identity, building and lift type, operating mode, car-call and hall-call order, fault history, low-speed duration, current, temperature, sensor data, and corrective action. Compare the same measurements across units so one problematic car is not hidden by an average.

Return-to-service evidence for the affected lift

Keep a case record with the installed model, board revisions, software identification, legible drawings, motor and drive nameplate data, sensor identification, and exact operating mode. For call-priority complaints, attach the request and door event sequence. For floor passing, attach position, pulse, slowdown, and terminal-zone observations. For fault 45 or motor heating, attach the revision-matched fault definition, low-speed duration, current, and temperature measurements.

Close a fault only after the original symptom no longer reproduces in its relevant operating modes and the independent measurements agree with the installed documentation. A repeatable full-speed pass, an unexplained dispatch with passengers aboard, recurring fault, or motor temperature/current beyond documented limits is a stop condition under the site's service procedure—not a reason to suppress an input or bypass a protection circuit.

UEL elevator troubleshooting FAQ