Mikro MPR500 User Manual

MPR500 Motor Protection Relay User's Guide

Brief Overview

h Motor Protection Relay
i
t
6X
I >> t >>
o
t >> I >>
S
I << t
Start
t << t
Stall
I
B
t CT
I >> SW
o
Figure 1: Front panel overview
Symbols
a – Run LED
t – Thermal overload time constant
b – Trip/Pickup LED 6X
I>> – Short circuit/High set Overcurrent
c – Thermal LED
t>> – Short circuit/High set Overcurrent
d – Down key
I<
e – Up key
t<
– Unbalance
f – Reset/Mode key
– Unbalance delay time
t
g – Test key
I > – Earth fault
0
t > – Earth fault delay time
0
h – Data LED
I >> – Prolonged starting/stall rotor
S
i – Function LED
t – Prolonged starting delay time
Start
t – Stall rotor delay time
Stall
I – Base/full load current
B
CT – External current transformer ratio
SW – Soft switch
1. General Description
MPR500 is a motor protection relay that combines
Thermal Overload, short circuit, undercurrent, unbalance,
Phase Loss, phase sequence, lock/stall rotor and earth
fault protections.
MPR500 incorporates a 4-digit LED indicator which
allows direct numerical readout of set values, actual
measured value and system indication.
MPR500 has 2 relay outputs (R1 and R2). R1 is On
under normal operating condition to allow motor running,
and off during tripping. R2 is programmable to give signal
in various conditions.
A programmable binary input is provided to perform
various operations upon binary input triggering.

2. Display

2.1 Current and Thermal Capacity Display
During power up, when the relay is not under tripping
condition, the display shows current
thermal capacity %. The Function LED indicates which
parameter is being displayed. The Data LED showing
value.
Press "UP" or "DOWN" to scroll through the parameters.
delay time
– Undercurrent
– Undercurrent delay time
in ampere or
V1.3
a
b
c
I
L1
d
e
f
g
I
L2
I
L3
I
0
Thermal
Figure 2: Current and thermal capacity display
For current more than 1000A, a dot is shown behind
least significant digit. Eg: 1.25. = 1.25kA
I - Phase 1 current
L1
I - Phase 2 current
L2
I - Phase 3 current
L3
I - Zero sequence/Earth fault current
0
Thermal % - Thermal capacity % (Thermal overload trip-
ping at 100%)
During Thermal capacity display, thermal capacity can be
cleared to 0% by pressing "UP" and "DOWN" simultane-
ously for longer than 1.5 seconds.
Warning: Clearing thermal capacity effectively reset
to cold start condition, user is not encouraged to
clear thermal capacity unless it is sure that motor is
cool enough to run/start within its thermal limit.
1