Relays for motor protection

Electrical Power & Protection

January 2018 Electrical Power & Protection

Becker Mining’s Proloc and ProBeck electronic protection and control relays have been designed for motor protection and cable theft detection in diverse industries, including mining and quarrying, electrification, municipalities, water and wastewater, chemical, petro-chemical and general engineering. “Becker’s low voltage relays, with advanced technologies for dependable protection of electric motors used on pumps, fans, conveyors and compressors, can also be used as highly effective standalone cable protection systems, to guard against cable theft,” says Frikkie Quirk, senior general manager, electrical.

Becker relays are programmed to detect cable theft by identifying a change in impedance of cable up to 1100 V connected to a motor or pump. In the event of cable tampering, the unit sends an SMS, or activates an emergency alarm or siren. This system is capable of Scada visualisation and is able to communicate relevant information to a control room via an existing PLC. The Becker cable theft detection system, with real time and date, is able to log up to 1400 events, providing critical information, including when the alarm was activated and how long it took for someone to respond. The system needs to be reset at the location of the alarm in order to confirm response by security. When the reset facility is activated, the unit logs the date and time of the response. This protection system, which requires only 220 V or 110 V to power the unit, can also be used as a stand-alone unit to monitor cable without power. A battery backup facility for SMS communication provides power backup for up to eight hours.

Proloc and ProBeck electronic relays for motors (380 V, 400 V, 525 V, 950 V and 1100 V – 3,3 kV and 6,6 kV) have features for thermal overload protection, earth insulation lockout, frozen or vacuum contact failure and earth leakage protection. Other user-selectable features include short circuit, frequency and power factor measurement, as well as minimum load, overvoltage and undervoltage protection.

Becker protection relays are also used to control pumps and motors based on water levels, valve position, temperature sensors, time of day and moisture content of the soil.

These devices, which are able to detect dry run in boreholes, tanks and dams, can be programmed to automatically restart pumps after a specified time or set level. An important advantage of this system is a door mounted infrared link that enables a laptop with Proloc software to manage all settings and downloads, without having to open the panel door and expose personnel to dangerous live equipment. This safety feature is a critical requirement in the OHSA Act. No special licences are necessary for the software.

For more information contact Taryn Pretorius, Becker Mining South Africa, +27 (0)11 617 6300, [email protected], www.za-becker-mining.com

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Relays for motor protection

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