Vibrator Motors

Pokers of 38–45 mm call for a drive rated 1.5–2.0 kW on a 230 V / 50 Hz supply with a 3–4 m shaft. Such a set holds around 12 000 vibrations per minute even in a stiff mix of S2–S3 consistency. A 1.1 kW motor handles the same diameter only with a short shaft up to 2 m and intermittent work — with a longer casing the torque falls away and compaction stops being effective.

Generator supply is standard on sites without mains power, as long as the set is sized with a margin. A single-phase 1.1–2.3 kW motor draws several times its rated current at start-up, so a safe generator is rated about twice the drive — roughly 4–5 kVA for a 2.0 kW unit. A mechanical drive is a plain induction motor, so it copes with voltage swings better than converter electronics do. Power sources are grouped under single-phase 230 V generators.

Three figures settle a replacement: coupling type between motor and shaft, casing thread and permissible torque. Makers use their own quick-release systems, so the drive, the 1–6 m shaft and the 25–65 mm poker are usually kept within one brand. Power comes on top of that: a new drive is matched to the largest poker in the set, not to the one used most often. An adapter fitted without those checks usually snaps the shaft core.

Overheated windings caused by an undersized extension lead are the most common failure. A 1.5 mm² cable running 50 m can pull the voltage down by well over ten per cent, so a 2.0 kW motor draws more current and runs hotter. The second classic mistake is running a grit-filled shaft without grease, which loads bearings and coupling. A safe routine is at least 2.5 mm² of conductor beyond 25 m of lead, greasing the shaft after each day of pouring, and a cooling break after about an hour of continuous work.