P&B MPR3E5 - Page 32

17/12/97 Page 30 Issue H
THERMAL CURRENT / TIME CURVES
Relay Operating Time = t6x (seconds) x T
Curve Type Hot/Cold
Ratio
1 Cold Curve
2 Hot Curve 80%
3 Hot Curve 50%
4 Hot Curve 20%
1 10
0.1
1
10
100
Multiples of FLC
CURVE 2
CURVE 3
CURVE 4
CURVE 1
OVERLOAD
PICKUP OF
1.05xFLC
OVERLOAD
PICKUP OF
1.10xFLC
OPERATING
TIME
MULTIPLIER 'T'