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NEW PROLOC RELAY ELEVATES SAFETY IN THE MINING INDUSTRY

Product News Monday, August 20, 2012: NewElec (Pty) Ltd

EMIS Sales, part of the Becker mining group, commissioned NewElec to design a motor protection and control relay to meet the needs for coal mining flameproof feeder gate-end boxes, as well as flitting panel applications. The design criteria embraced all the conventional motor protection, as well as earth leakage and short circuit protection, and in addition, had to meet the following requirements.

The relay had to feature integrated selectable starter control for DOL and reversing starters. It had to accommodate six preset settings for different motor sizes, downloadable from the door- mounted MMI by operational staff. Indication of the setting selection had to be displayed to allow the supervisory staff to monitor the relay. In addition, the relay had to protect against contactor / vacuum failure or frozen contactor conditions, protect and provide against earth insulation lock out, earth leakage, and earth faults. Lastly, the relay was required to maintain a nonvolatile date and time stamped 1 700 event and 50 fault record with a download facility into Excel with drive and panel identification via an IRDA link and an IS approved uploading and downloading handheld MMI.

These challenges were fully met with the launch of the EMIS ProLoc motor protection relay now available through EMIS Sales.

In brief, the Proloc relay provides protection against all the usual electric motor winding failure causes but includes enhanced features such as timers, latch circuit, back-spin timer, unauthorized current detection, start stall detection using power factor measurements and dry run / load loss detection by a user-selected method (current or power factor). Proloc also features priming time delay timers as well as starts per hour / consecutive start attempt limitation, earth leakage and earth fault detection and protection related to over / under voltage, phase rotation and over/under frequency.

Starter logic for DOL, and Star Delta circuits – reversing and standard, are easily configured. The associated software also permits customized user labeling of inputs and outputs for clearer identification of faults and commissioning of motors in various applications. Three logic function blocks are included each having up to three variables and an interlink capability. The Proloc arrangement accommodates four inputs and five programmable output contacts.

In a flitting panel application the relay is easily re-paramatized to suit the requirements of the related electric motor by simply selecting the saved memory setting that resides in the ProLoc man machine interface. Up to six memory slots are available. Personnel safety is enhanced by the Proloc relay that back-trips the main breaker on detection of a frozen contactor pole so as to eliminate the possibility of electrocution. The pre-start insulation lockout feature also assists in preventing the loss of a motor by not allowing the start to take place if the motor has an insulation problem.

The Proloc relay stores a variety of data about the motor in useful files. Up to 1 700 events and 50 last faults in rotating buffers are available for viewing via the MMI touch keys. However the management tools go beyond this basic information. Real versus apparent power measurements may be examined for efficiencies and fault reports, including the measurement of actual load currents, thermal capacities, voltages present, power factor and circuit breaking times.

In line with new demands from training facilities, the software includes a simulation mode that assists training personnel to better understand the workings of this modern protection device. Contact EMIS Sales or NewElec for further information.