Shaft speed switches by Electro-Sensors detect equipment slowdown and stoppage

The Electro-Sensors DR1000 series

Electro-Sensors measurement solutions are available through Durham Instruments, like the DR1000 series of shaft speed switches. Each unit is a complete precision rotation-monitoring system, perfect for detecting unwanted slowdown or stoppage of process equipment, including pumps, drive trains, power-driven components, screw conveyors, and exhaust fans.

The DR1000 series features precise setpoint capability over many speeds starting at ½ a revolution per minute (rpm), making it ideal for super-slow-speed applications.

Simple field calibration, setup

Also recommended for crushers, tail pulleys, and elevators, the DR1000 series monitors shaft speeds, detecting shaft slowdown to within one per cent of the setpoint. A DPDT control relay, rated at 5A at 30 Vdc/l20Vac resistive, functions as the output. Durham Instruments recommends these digital speed switches for the general manufacturing, aerospace, automation, food-processing, forestry, medical, military, mining, packaging, power-generation, alternative-energy, and transportation sectors and for research and development.

These shaft speed switches are updated substitutes for the R-series of speed switches. Among their key features: digital circuitry; simple field calibration and setup; ETL approval according to relevant UL and CSA standards; NEMA 4X.7- and 9-rated cast aluminum switch housing; and set-point range from ½ to 5,000 rpm. Optional features include explosion-proof sensors and alternate voltages.

For rotational failure, the DPDT relay can be used for equipment shutdown or to provide an alarm. The DR1000 series bring efficiency and safety to operations by preventing equipment damage, product waste, and downtime. Each unit functions as a system with a remote/external-pulse frequency output sensor and a pulse generator, sold separately. The switch is failsafe, and any malfunction will de-energize the control circuit.

The most common DR1000 system consists of a 906 or 907 XP hall-effect sensor and a 255 pulser disc. The disc is shaft-end-mounted and generates an alternating magnetic field that the large-gap sensor picks up. The sensor transmits this speed signal as a digital pulse (frequency) to the switch through three-conductor shielded cable. The unit decodes this frequency signal to determine shaft speed and compare this to the pre-adjusted setpoint.

For more information, contact Durham Instruments.

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