Thermolec Application &Technical Notes - Manual (Page 31)

STEP 3 - (continued)
Since the SCR step is kept relatively small (53.3 Kw ), it is still cost effective
compared to a full SCR 160 KW.
In the following graphic, the sequential loads are switched ON and OFF to match the heat demand.
Lay a straightedge vertically at any position of the control input voltage and find exactly which stages are
ON or OFF. The SCR not only fill the gaps but overlaps the gaps between the fixed steps at all times.
Hybrid Sequential Load Diagram
THREE EASY STEPS
Q4
Q3
Q2
0 V
Q1
Q3
Q2
Q1
Q2
Q1 Q1
Load
Total Load
Q4
Q3
Q2
Q1
SCR Output Q5
Relay ON / OFF
Sequential Outputs
The SCR Output
fills the gap between the fixed steps
Control Signal Input
2 /
16
4 /
16
6 /
16
8 /
16
10 /
16
12 /
16
14 /
16
16 /
16
1
0
1
0
1
0
1
0
1.25 V
2.5 V
3.75 V 4.38 V
5 V
6.25 V
7.5 V
8.13 V 8.75 V
10 V