Current Input Transfer Function - Trane CVHE Troubleshooting Manual

Starter Module CT Voltage and Currents
There are two configurations of CTs used. One is the single stage, the other is the dual stage. A
different transfer function exists depending on whether a single or dual stage configuration is
used. The two configurations appear the same to the UCP2 by normalizing each. Thus a different
equation is used to take the actual line current and convert it to a common 'Normalized Line
Current' that may be used in
the current input terminal pairs of the Starter module. These pairs are J5-1,2, J5-3,4 and J5-5,6.
For a single stage CT:
Normalized Line Current
For a two stage CT:
Normalized Line Current
Table 23-Current Input Transfer Function
Normalized Terminal
Line Input Current
Current (mA RMS)
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100 100
105 105
110 110
CVHE-SB-32A
Table 23
. Note that the 'Terminal Volts' is the AC voltage seen at
(
%) = Actual Line Current(Amps)*100%*Primary Turns CT-Rated
(%
) = Actual Line Current(Amps)*138.89%*Primary Turns Line CT
Terminal
Volts (V RMS)
(± 5%)
0 0
5 1.19
10 1.37
15 1.53
20 1.67
25 1.81
30 1.95
35 2.09
40 2.23
45 2.36
50 2.50
55 2.63
60 2.77
65 2.90
70 3.03
75 3.17
80 3.30
85 3.43
90 3.57
95 3.70
3.83
3.96
4.10
Primary Current (Amps)
Rated Primary Current (Amps)
Normalized
Line Input Current
Current% (mA RMS)
115
120
125
130
135
140
145
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
Terminal Terminal Volts
(V RMS) (±
5%)
115 4.23
120 4.36
125 4.49
130 4.62
135 4.75
140 4.88
145 5.02
150 5.15
160 5.41
170 5.67
180 5.94
190 6.20
200 6.46
210 6.72
220 6.99
230 7.25
240 7.51
250 7.77
260 8.03
270 8.29
280 8.56
290 8.82
300 9.08
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