Alpha EM DC 6000, Operating Manual

Page: 41 / 48

1) High alarm & Energised relay
Input
Relay De-energise
Relay Energise
Trip point
Hysterisis point
Time
50%
25%
2s 3s
2) High alarm & De-energised relay
Input
Relay Energise
Relay De-energise
Trip point
Hysterisis point
Time
50%
25%
3s 2s
a)Trip point = 50%
Hysterisis = 50%
Absolute hyteresis value = 50% - (50% of 50)
= 25%
a)
b)
a)
b)
Examples for Different Configurations
Energizing delay = 2s De-energizing delay = 3s
Input
Relay Energise
Relay De-energise
Trip point
Hysterisis point
Time
-50%
-25%
3s 2s
b)Trip point = -50%
Hysterisis = 50%
Absolute hyteresis value = - [50% - (50% of 50)]
= -25%
Input
Relay De-energise
Relay Energise
Trip point
Hysterisis point
Time
-50%
-25%
2s 3s
0
0
0
0
Example:
Nominal value = 48 V,
Trip point (%) = 60%,
Hysteresis (%) = 25 %
Trip value = 60% of 48V = 28.8V
High alarm Hysteresis value = 25 % of 28.8 V = 7.2 V
So, relay will trip above 28.8 V & it will reset below 21.6 V (28.8 V - 7.2 V)
For negative values of trip point, calculations will be the same as positive trip point. Only a negative sign is applied to
calculated hysteresis value.
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