22 Jul 2024


Motor monitor gives an early warning of plant problems

At the 2008 Hannover Fair, Pilz unveiled a motor monitor that indicates the motor load through the true power being drawn. The company says that the PMD s10 monitor can provide an early warning of hazardous plant conditions, without needing extra sensors.

Pilz PMD monitor

The device (shown above) can monitor AC or DC motors rated up to 11kW directly, and larger machines via current transformers. It can be also be used with frequency-controlled drives.

The device monitors thresholds, and provides an analogue voltage or current value proportional to the true power. Both overload and underload thresholds can be monitored via a PLC or an integrated relay.

Peak values can be stored and viewed on a built-in display, which can also show parameters such as power consumption during normal operation.

Pilz suggests that the monitor could provide early warnings of potentially dangerous plant conditions. For example, wear and tear on mechanical components such as bearings could be identified before a failure occurs, avoiding costly mechanical damage, downtime and possible hazards to personnel. It could also be used to monitor conveyors for blockages and fans for dirt built-ups.

The PMD s10 can process frequencies from 0–1kHz and can handle motor voltages up to 550V. Motor start-up and transient power fluctuations can be suppressed to eliminate the effects of high in-rush currents.

The device is part of a new generation of electronic relays for monitoring values such as voltage, current, temperature or phase sequence. Values can be set simply via a rotary knob and then saved onto a memory card. The data can then be copied to other similar relays.