513.1 Motor/gearbox selection

Match torque/speed to stroke and duty. Proper selection keeps HVM bollard timings within spec.

Start with bollard stroke length, target raise/lower time, and frictional load. From these, derive required shaft torque and select a motor/gearbox pair that delivers speed with headroom. Use an PLC/Controller ramp/accel profile to avoid shock at starts/stops. Consider self-locking screwjacks vs helical gears where holding torque matters (see 513.3). For multi-lane arrays, coordinate motor sizes to simplify spares.

Validate the choice against array throughput targets (see KPI set: cycle time & MTBF). If site duty is intermittent, prefer high-efficiency motors that run cool in GCC heat (link 337). Where utilities are constrained, check inrush and recommend soft starters or VFDs.

513.2 Duty cycle & thermal limits

Quantify S3/S4 duty and install thermal guards (341). Staying within limits preserves crash rated bollard availability.

Document the expected operations/hour and sequence length, then map to IEC duty types (e.g., S3 intermittent, S4 starting). Size motors for worst-case ambient and enclosure rise (see Enclosure Heat-Load Estimator) and add a thermal alarm for early warning. Protect with over-temp trips and log events to the remote fault log.

Where queues peak, use predictive maintenance counters to throttle or shed load gracefully before thermal cut-outs cause outages. For desert sites, derate per the enclosure IP rating and provide forced ventilation or heat exchangers if needed.

513.3 Brake & hold functions

Use failsafe brakes or self-locking screws. Holds maintain safe HVM bollard positions on power loss (355).

Define a clear fail-state philosophy: for security lanes, a normally-energized brake with Fail-safe (up) may be justified, while public throughput lanes might prefer Fail-secure (down). Screwjacks provide inherent holding but require protection from dust ingress. Always include manual release with a documented LOTO procedure.

513.4 Encoder/limit sensing

Redundant end-stops and encoders give precise positioning. Accurate sensing protects crash rated bollard interlocks (352).

Combine hard end-stops with dual limit switches and a shaft encoder for position verification. Tie encoder plausibility to the interlock matrix so unsafe moves are inhibited. Provide a watchdog timer and Safe torque off (STO) where applicable. Specify cable shielding and route sensing looms away from HPU pumps or VFDs to reduce EMC noise.

513.5 Shock/impact tolerance

Specify mounts and couplings that absorb hits. Tolerance avoids HVM bollard misalignment after incidents.

Even certified crash ratings don’t guarantee the drive escapes unscathed after real impacts. Use compliant couplings, anti-backdrive features, and shear-key strategies so primary damage is predictable and quick to repair. Provide alignment jigs and a post-incident inspection checklist to verify capture height, straightness, and clear-gap after any event.

513.6 Lubrication & sealing

Choose greases/seals for heat and dust (363). Sealing keeps crash rated bollard drives serviceable.

Specify high-temperature, water-resistant grease with anti-wear and corrosion inhibitors. For sand-laden sites, select double-lip or labyrinth seals and fit breathers with membrane vents. Add a drain tap at the lowest enclosure point and route a drip loop on cables. Define service intervals in the Preventive Maintenance Plan.

513.7 Noise & vibration

Set dB limits and isolation (546). Quiet drives keep HVM bollard lanes compliant.

Adopt site dB targets and verify against the acoustic environment (night operations near residences, hospitals, or hotels). Use elastomer isolators and tuned soft-start/stop to cut structure-borne noise. Line panels with acoustic lining where heat allows, and treat air paths with baffles. Reference Acoustic limits for HPUs/enclosures for acceptance bands and test methods.

513.8 Spares interchangeability

Standardize motors, gearsets, and brakes (842). Interchangeability shortens crash rated bollard downtime.

Define a spares policy that minimizes unique variants across lanes. Prefer common frame sizes and connector standards (pre-terminated looms, printed ferrules). Capture serials in the Asset Register and tie replacements to SAT re-witness where safety chains are affected.

513.9 Commissioning tests

Prove torque, stroke time, and stop accuracy (636). Tests validate automatic HVM bollard performance.

Execute a structured sequence: (a) no-load run-in; (b) torque verification vs spec; (c) stroke time and repeatability at nominal and hot conditions; (d) end-stop overrun checks; (e) interlock matrix verification; and (f) soak tests with counters trending to establish baseline MTBF. Record evidence per SAT / Witness Procedure with clear acceptance bands.

513 Electromechanical Drives — FAQ