AKM 345 Gen2 Instruction Manual
(Rev No. ECN-27992)
7
www.qualitrolcorp.com
The AKM 345 TD50(5 AMP) option allows for the input of up to 5 amps winding temperature
simulation current without the expense or additional wiring required by an external matching
unit. It is available with up to 4 switches. 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 Figure 3.
•
Accuracy of 2.2A output at 5A input:
+/-5% at 0 - 1.6
Ω
secondary load
+/-10% at 1.6 - 1.8
Ω
secondary load
•
Max continuous primary current: 6A
•
Max primary current: 10 a for 2 minutes
5.5. 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.
5.5.1. Method A
•
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 (see Section 5.1 instructions).
•
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.
5.5.2. Method B
•
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 (see Section 5.1instructions).
•
Jumper between one pin of the "R" connector and one pin of the “I” connector, and
connect an ammeter between the remaining two pins, as shown.
•
Input the desired primary current at positions 5-5 on the terminal block and note the
current flowing in the circuit. You now have the exact ratio of input to output current at
secondary load. Disconnect power before disconnecting the ammeter and jumper– the
secondary leads must always be connected in-circuit or shorted when the CT is
powered.
•
Using the measured secondary current, re-calculate the desired R5-5 value which will
provide the exact heater current necessary for the desired winding simulation. Using
an ohmmeter at the “R” pins, adjust the matching resistance to meet this R5-5 value.
