Application; Features And Characteristics - P&B MPR3E5 Manual

2. Application

The MPR 3E5 is a universal digital adjustable motor protection relay. It serves as overload,
overcurrent, negative sequence (unbalance), and general protection for synchronous and induction
machines. With a large selection of adjustment possibilities, the MPR 3E5 is suitable for almost any
type of machine.
The protective functions of the MPR 3E5 are summarised as follows:
Thermal Overload protection with adjustable current/time curves and selectable hot/cold
•
ratios.
Overload Pre-Alarm with a separate output relay.
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Low Set and High Set Overcurrent Protection
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Single Phasing Protection
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Start Limiter
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Earth/Ground Fault Protection.
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Unbalance (Negative Phase Sequence) protection.
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Incorrect Phase Rotation protection.
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Undercurrent Protection (Definite Time).
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Stall protection using a speed switch input.
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Fully Programmable Output Relay operation.
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Fault trip inhibit setting for Contactor Applications.
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3. Features and characteristics

Complete digital processing of the sampled measured values
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Digital filtering of measured values using discrete Fourier analysis to suppress
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high frequency harmonics and D.C. component induced by faults or system
operations
Self adjusting sample frequency for operation between 40 - 70Hz.
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Extremely wide setting ranges with fine setting steps
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Unauthorised user access control through password protection
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User defined password
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Continuous self-supervision of software and hardware
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Outstanding design flexibility for easy selection of appropriate operational scheme
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for numerous applications
Numerical display of setting values, actual measured values and memorised fault data etc.
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Setting, Measured and Fault Parameters available via RS485 serial link.
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Wide voltage range for DC or AC power supply
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Withdrawable modules with automatic short circuit of C.T. inputs
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14/1/98 Page 3 Issue H