Can you balance at such low RPM (300)?

Yes. Balanset-1A works reliably from 250 RPM upward. The key is a clean tachometer signal and stable operating speed. At 300 RPM the sensor integration time is longer (20 s recommended), but accuracy is not affected.

How do you attach correction weights to a crusher flywheel?

Correction weights are typically welded to the flywheel rim or bolted using pre-drilled holes. In this case, weights were arc-welded to the inner rim face. For temporary verification, C-clamps or hose clamps work well.

Is two-plane balancing needed for a crusher?

The flywheel assembly on this crusher has a width-to-diameter ratio of 0.4 and two separate bearing supports. Two-plane balancing eliminates both static and couple imbalance — single-plane would leave residual vibration on the far bearing.

Jaw Crusher Drive Shaft Balancing — Quarry in Brazil

Background

A granite quarry 80 km north of Belo Horizonte operates a PE-400×600 jaw crusher processing 60 tonnes per hour. The crusher runs at 300 RPM with a 420 kg cast-iron flywheel on each end of the eccentric shaft. After a liner change, the drive-end flywheel developed a pronounced vibration that worsened over two shifts.

Baseline measurement with a handheld meter showed 14.8 mm/s RMS on the drive-end bearing and 11.2 mm/s on the non-drive-end. Both values exceeded the plant’s alarm threshold of 7.1 mm/s. Previous practice was to remove the flywheel by crane and truck it to a balancing shop in São Paulo — a 14-day round trip including transit and queue time.

Setup

The crusher was locked out and allowed to cool. Two vibration sensors were magnetically mounted on the horizontal axis of each bearing housing — drive-end (DE) and non-drive-end (NDE). The tachometer reflective tape was applied to the flywheel rim, visible through an inspection window. All cables were routed clear of pinch points and secured with zip ties.

Balanset-1A was configured for two-plane balancing at 300 RPM with 20-second integration windows.

Measurement

Run 1 — Reference.
Crusher started unloaded (no material feed). Readings at stable 300 RPM:

DE: 14.8 mm/s RMS, phase 78°
NDE: 11.2 mm/s RMS, phase 194°

Strong 1× component on both channels. The 116° phase difference between bearings confirmed couple imbalance — confirming two-plane balancing was the right call.

Run 2 — Trial weight on Plane 1 (DE flywheel).
A 250 g trial weight was bolted to the flywheel rim at 0°. Run recorded:

DE: 10.1 mm/s, phase shifted to 142°
NDE: 9.8 mm/s

Influence coefficients calculated.

Run 3 — Trial weight on Plane 2 (NDE flywheel).
DE trial weight removed. A 250 g trial weight placed on NDE flywheel at 0°. Run recorded.

Software now had the full 2×2 influence coefficient matrix and computed correction vectors:

DE flywheel: 185 g at 312°
NDE flywheel: 130 g at 47°

Run 4 — Correction verification.
Correction weights arc-welded to the inner rim face of each flywheel. Final unloaded run:

DE: 2.3 mm/s RMS
NDE: 1.8 mm/s RMS

Both readings comfortably within ISO 10816-3 Zone A. The crusher was returned to production with material feed — vibration remained stable at 2.5 mm/s DE and 2.0 mm/s NDE under load.

Result

Total elapsed time from lockout to return-to-service: 55 minutes. No crane, no transport, no two-week wait. The quarry estimated the avoided downtime at approximately R$ 85,000 (≈ US$ 16,000) in lost production — the Balanset-1A paid for itself on the first use.