Speed monitoring RC3
RC3 speed monitoring for escalator motors – TÜV-tested in accordance with EN 115:2008, six nominal frequencies (66⅔ to 500 Hz), automatic self-test, DIN rail mounting
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RC3 speed monitoring for escalators
Why is the speed monitored on escalators?
Speed monitoring is a safety-critical element in every escalator. According to the European standard EN 115:2008, escalators must be equipped with a reliable speed monitoring system that switches off the motor immediately in the event of dangerous speed deviations. An incorrect speed can lead to serious accidents – whether due to sudden acceleration (overspeed), unexpected braking (underspeed) or a reversal of direction.
The RC3 speed monitor from RLS Wacon is a TÜV type-tested safety component that has been used successfully in escalators and moving walks worldwide for many years. It reliably monitors three speed ranges and detects four different hazardous conditions, each of which leads to the escalator motor being switched off immediately.
How does the RC3 speed monitor work?
The RC3 detects the speed of the escalator motor via two inductive proximity switches (NAMUR sensors), which are attached to the flywheel of the motor. The sensors are supplied with 9 V DC directly from the device (max. 50 mA per output) and do not require an external voltage source. Both 2-wire sensors (NAMUR) and 3-wire sensors can be adapted.
The device continuously monitors three speed ranges and distinguishes between four switch-off criteria:
| Switch-off criterion | Threshold value | Reaction |
|---|---|---|
| Underspeed | < 19.5 % RPM | Shutdown after 2.6 seconds |
| Overspeed | > 117 % RPMN | Immediate shutdown |
| Reversal of direction of rotation | Drop from > 19.5 % to < 19.5 % UPMNENN | Immediate shutdown |
| Sensor failure | Short circuit, interruption, oscillation | Immediate shutdown |
Each time the mains voltage is switched on, the RC3 performs an automatic self-test (max. 2.8 seconds). The sensors are switched off and all four switch-off conditions are simulated by an internal sweep generator. Only after a successful self-test and closed motor contactor contact does the green “NORMAL” LED light up and the output relays enable the motor.
The safety output for staircase control contains two potential-free normally open contacts (terminals 17/18) connected in series internally, which are looped into the safety chain and protected against overload with fuse F2 (2 Atr.). The STATUS terminal strip also has potential-free contacts for the status signal (NORMAL/FAULT) and a conditioned sensor signal (optocoupler output).
The first fault leading to shutdown is indicated by one of the four LEDs on the front panel (LO, HI, SENS FAIL, NORMAL). The device can only be reset by pressing the RESET button – locally or via the external RESET input (pin 1/2) – after it has been checked by qualified personnel. In the event of a sensor fault or internal error, a restart is not possible without prior troubleshooting.
Available sensor nominal frequencies
The RC3 is available in six different nominal sensor frequencies. The nominal frequency corresponds to the pulse frequency of the sensor at 100 % nominal speed of the escalator motor:
| Nominal frequency | Item no. Vertical | Item no. horizontal |
|---|---|---|
| 66⅔ Hz | 80-200300 | 80-200304 |
| 80 Hz | 80-200303 | 80-200305 |
| 100 Hz | 80-200301 | 80-200306 |
| 250 Hz | 80-200302 | 80-200307 |
| 333 Hz | 80-200311 | 80-200314 |
| 500 Hz | 80-200315 | 80-200316 |
Advantages of speed monitoring RC3
- TÜV type-tested in accordance with EN 115:2008
Certified safety for use in escalators in accordance with the European standard
- Six nominal sensor frequencies available
66⅔, 80, 100, 250, 333 and 500 Hz – suitable for various gear ratios and cam numbers
- Automatic self-test every time the device is switched on
All four switch-off conditions are simulated internally – maximum operational safety
- Four independent switch-off criteria
Underspeed, overspeed, reversal of direction of rotation and sensor failure are reliably detected
- Compact design with DIN rail mounting
64 × 104 × 135 mm – easy installation in the switch cabinet, vertical or horizontal
- Low power consumption under 5 VA
Energy-efficient in continuous operation at 230 V AC
- Integrated sensor supply 9 V DC
No external voltage source required for the proximity switches – 2-wire (NAMUR) and 3-wire compatible
Field of application
The RC3 speed monitor is used in escalators and moving walks for standard-compliant speed monitoring in accordance with EN 115:2008. It monitors the drive motor via inductive proximity switches on the flywheel and reliably switches off the motor in the event of dangerous speed deviations.
Installation and commissioning
Two speed sensors and a potential-free contact from the contactor are required to operate the device.
- Mount the device in the switch cabinet – vertically (screw mounting) or horizontally (DIN top-hat rail, mounting clip included)
- Attach two inductive proximity switches (NAMUR or 3-wire) to the flywheel of the motor
- Connect sensors to the 8-pin input terminal strip: Sensor 1 to pin 9/10 (+9V to pin 11 if necessary), sensor 2 to pin 12/13 (+9V to pin 14 if necessary)
- Connect potential-free contact of the driving contactor: either to input M (pin 15/16, 12 V) or to MH1/MH2 (pin 19/20, 230 V AC) – not both at the same time!
- Loop the safety output (terminals 17/18) into the safety chain of the staircase control – fused with F2 (2 Atr.)
- Connect 230 V AC mains voltage to terminals 21/22/23 – Connect earth terminal (23) to central earth
- Switch on mains voltage – automatic self-test runs (max. 2.8 s)
- After a successful self-test, the green “NORMAL” LED lights up – the motor can be started
Tip for the installation
Use shielded sensor cables. For NAMUR sensors (2-wire), the cable resistance must not exceed 100 Ω. Separate supply voltages of +9 V (max. 50 mA per output) are available for 3-wire sensors. To prevent the contactor contact from oxidizing, we recommend using the 230 V input MH1/MH2 (pin 19/20).
Important notes
- The device must be connected to the central earth at the earth terminal – operation without earthing can lead to malfunctions
- Only the type-tested safety contacts (terminals 17/18) may be used for speed monitoring
- The documentation is part of the system and must be stored in the switch cabinet (TÜV regulation)
- A RESET after a fault shutdown may only be carried out after the escalator has been checked by qualified personnel
- Simultaneous use of both motor contactor inputs (M and MH) is not permitted
- If the sensor signals are not plausible, the motor is switched off – a restart is only possible after the fault has been rectified
- When switching inductive loads at the STATUS outputs (FAIL/NORMAL), suitable protective circuits (varistor or similar) must be used
Specifications at a glance
| Property | Value |
|---|---|
| Operating voltage | 230 V AC ±10 %, 40 – 60 Hz |
| Power consumption | < 5 VA |
| Switching current safety output | 2 A (max. 8 A), fused with F2 (2 Atr.) |
| Mains fuse | F1 (0.125 Atr.) primary side |
| Temperature range | -20 °C to +65 °C |
| Sensor type | Inductive proximity switch (NAMUR) or 3-wire |
| Sensor operating voltage | 9 V DC (max. 50 mA per output) |
| Sensor lead resistance (NAMUR) | max. 100 Ω |
| Nominal frequencies | 66⅔, 80, 100, 250, 333, 500 Hz |
| Switch-off criterion underspeed | < 19.5 % RPM (after 2.6 s) |
| Overspeed switch-off criterion | > 117 % RPMN |
| Switch-off criterion Reverse direction of rotation | from > 19.5 % to < 19.5 % UPMNENN |
| Sensor failure | Short circuit, interruption, oscillation |
| Self-test | Automatic every time the device is switched on (max. 2.8 s) |
| Dimensions (W × H × D) | 64 × 104 × 135 mm |
| Dimensions incl. plug connector | 64 × 104 × 145 mm |
| Dimensions incl. plug connector and mounting clip | 64 × 104 × 152 mm |
| Housing | Shielded plastic housing |
| Vertical mounting | Screw mounting (without mounting clip) |
| Horizontal mounting | DIN top-hat rail (mounting clip included) |
| Safety output | 2 potential-free normally open contacts connected in series (terminals 17/18) |
| Status output FAIL | Solid state relay, max. 400 V AC/DC, max. 100 mA (pin 5/6) |
| Status output NORMAL | Solid state relay, max. 400 V AC/DC, max. 100 mA (pin 7/8) |
| Sensor output | Optocoupler, max. +70 V DC, typ. 10 mA (pin 3/4) |
| External RESET | Potential-free normally open contact, 100 ms – 2 s (pin 1/2) |
Scope of delivery
| Component |
|---|
| 1 × speed monitoring RC3 (configured for selected nominal frequency) |
| 1 × fastening clip for DIN rail mounting (only for horizontal installation version) |
| Technical documentation |
Standards and certifications
| Standard | Description |
|---|---|
| EN 115:2008 | Safety of escalators and moving walks |
| EN 50081-1 | Electromagnetic compatibility – Generic standard Emission |
| EN 50082-1 | Electromagnetic compatibility – Generic immunity standard |
| DIN EN 12015 | EMC – Emission of elevators, escalators and moving walks |
| DIN EN 12016 | EMC – Immunity of elevators, escalators and moving walks |
| EN 61508 | Functional safety |
| EN 954-1 | Safety of machinery – Safety-related parts of control systems |
TÜV type-tested: All 230 V versions are TÜV BG type-tested in accordance with EN 115:2008.
Additional information
| Nominal speed | 66 Hz, 80 Hz, 100 Hz, 250 Hz, 333 Hz, 500 Hz |
|---|---|
| Direction |
