QUALITROL AKM345 GEN3 OTIWTI
TM
Instruction Manual
40-08847-00-Rev001
www.qualitrolcorp.com
Page 27 of 34
7.2
Using the Internal 5 Amp CT Option
–
TD50(5AMP)
7.2.1
Background
The AKM345 GEN3 TD50(5AMP) option allows for the input of up to 5 Amp winding temperature simulation
current without the expense or additional wiring required by an external matching unit. It is available with up
to 6 switches with some limitations on additional features. The 5 Amp option employs an internal CT which
accepts 5 Amps at the primary and outputs 2.2 Amps at the secondary. The secondary current is in parallel
with a standard TD50 matching resistance and heater. For temperature rise calculations please refer to the
Temperature Gradient Adjustment Graph
in section 7.1.
•
Accuracy of 2.2A output at 5A input:
o
±5% at 0 -
1. Ω se ondary load
o
±10% at 1.6 -
1. Ω se ondary load
•
Max continuous primary current: 6A
•
Max primary current: 10A for 2 minutes
7.2.2
Setting the Matching Resistance
There are two methods of setting the matching resistance depending on the accuracy required. Use Method A
for maximum ease of use and Method B for maximum accuracy.
7.2.2.1
Method A
Step 1)
Calculate the Is in Amps from your BCT at 100 % transformer load. Use the Is from the BCT as an
input to the internal in the W ™ KM 5 and al ulate the output urrent using a ratio of 5
to 2.2 A
•
Output current = Is (2.2/5)A
Step 2)
Disconnect the white separable connector and using an ohmmeter at the "R" pins. Adjust the
matching resistance to meet the target R5-5 value which will provide the desired heater current
according to section 7.1 instructions using as an input the output current calculated above.
Step 3)
Re-
connect the white separable connector. After the matching resistance has been set and the
white connector is re-mated, the winding simulation input current is wired to the terminal block at
the 5-5 positions as shown in the
TD50(5AMP) Wiring Example
below.
7.2.2.2
Method B
Step 1)
Calculate the Is in Amps from your BCT at 100 % transformer load. Use the Is from the BCT as an
input to the internal in the W ™ KM 5 and al ulate the output urrent using a ratio of
5A to 2.2A
a.
Output current = Is (2.2/5)A
Step 2)
Dis onne t the white separable onne tor and using an ohmmeter at the “ ” pins
adjust (as above
in 7.2.2.1 Step 2) the matching resistance to meet the target R5-5 value which will provide the
desired heater current according to section 7.1 instructions using as an input the output current
calculated above.
