4B - W4005 BÜHLER ELEVATOR MONITORING SYSTEM R9.6 – 22 May 2020
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10.15.1.
Underspeed Alarm – Belt Slipping
This condition is detected by constantly measuring the speed of the bottom shaft (single speed mode) or by
comparing the speeds of top and bottom shafts (differential speed mode). The behaviour is different
depending on the speed mode selected.
Detected Speed
Condition
Stop
Relay Delay
Single Speed Mode
<90% of calibrated speed (PPM)
Underspeed Alarm
5s
<80% of calibrated speed (PPM)
Severe Underspeed Alarm
1s
>110% of calibrated speed (PPM)
Overspeed Alarm
5s
>120% of calibrated speed (PPM)
Severe Overspeed Alarm
1s
Differential Speed Mode
<90% of calibrated speeds fraction
Underspeed Alarm
5s
<80% of calibrated speeds fraction
Severe Underspeed Alarm
1s
>110% of calibrated speeds fraction
Overspeed Alarm
5s
>120% of calibrated speeds fraction
Severe Overspeed Alarm
1s
Table 14 – Speed Alarm and Stop Delays
Speed Start Up Delays
Speed Start Up Delay
10s/30s (switch selectable)
Jam Detection
<25% of calibrated speed reached after 5s /10s, depending on Start Up
Delay selected
Table 15 – Speed Start Up Delays
A switch selectable start up delay is used for speed monitoring. During this start up delay the speed is not
monitored. Additionally, elevator Jam/Block detection is implemented in the W4005NV46AI /B controller. If
after the delays specified in Table 15
the speed of the elevator has not reached at
least 25% of the calibrated speed, the W4005NV46AI /B will assume that the elevator is jammed and will
stop the elevator immediately without waiting for the startup delay to elapse.
10.15.2.
Belt Misalignment Alarm
The W4005NV46AI /B has two belt alignment zone inputs designed to be used for top and bottom elevator
belt misalignment detection. The system comes with four TouchSwitch sensors included in the package. If
additional belt alignment monitoring is needed, then additional sensors can be wired in series to the existing
ones. There is a start-up delay during which the misalignment alarms are ignored by the W4005NV46AI /B.
After this period, the Stop Relay Delay will be as detailed in Table 16.
Misalignment Conditions
Time [s]
Misalignment Start Up Delay
20s
Misalignment Stop Relay Delay
15s
Table 16 – Misalignment Alarm Delays
10.15.3.
Hot Bearing Temperature Alarm
Four NTC type bearing temperature sensors can be connected to the W4005NV46AI /B controller as shown
in Figure 12. The inputs will be constantly monitored for the following conditions:
