14/1/98
Page 3
Issue H
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.
•
Low Set and High Set Overcurrent Protection
•
Single Phasing Protection
•
Start Limiter
•
Earth/Ground Fault Protection.
•
Unbalance (Negative Phase Sequence) protection.
•
Incorrect Phase Rotation protection.
•
Undercurrent Protection (Definite Time).
•
Stall protection using a speed switch input.
•
Fully Programmable Output Relay operation.
•
Fault trip inhibit setting for Contactor Applications.
3. Features and characteristics
•
Complete digital processing of the sampled measured values
•
Digital filtering of measured values using discrete Fourier analysis to suppress
high frequency harmonics and D.C. component induced by faults or system
operations
•
Self adjusting sample frequency for operation between 40 - 70Hz.
•
Extremely wide setting ranges with fine setting steps
•
Unauthorised user access control through password protection
•
User defined password
•
Continuous self-supervision of software and hardware
•
Outstanding design flexibility for easy selection of appropriate operational scheme
for numerous applications
•
Numerical display of setting values, actual measured values and memorised fault data etc.
•
Setting, Measured and Fault Parameters available via RS485 serial link.
•
Wide voltage range for DC or AC power supply
•
Withdrawable modules with automatic short circuit of C.T. inputs
