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How to use a 3-phase line reactor for a single-phase application!

The illustration below demonstrates how a 3-phase line reactor can be used for a single-phase application. Using the mathematical method below you can calculate the inductance to determine what type of reactor is needed.

REACTORS FOR SINGLE PHASE APPLICATIONS
MTE three-phase Line / Load Reactors can be used for single-phase applications by routing each of the two supply conductors through an outside coil, and leaving the center coil disconnected. For the drive input application shown in (Figure below), the incoming supply lines connect to terminals A1, C1, and outgoing lines from A2, C2. The "B" terminals for the center coil are not connected. The sum of the inductance of the two coils is the total inductance applied to the circuit.

As an example, consider a single-phase application of 2HP supplied by 240 Vac. The reactor must carry 12A (fundamental current) according to the NEC table for single-phase motor current. A 5% impedance is desired. For a 60Hz supply, the formula to calculate required inductance is: L = (ZV) / (377I), where L is inductance in Henries, Z is percent impedance, V is supply voltage, and I is full load amps.

For above example: 0.00265 = (0.05 x 240) / (377 x 12), indicating a total required inductance of 2.65 mH. Based upon this result, MTE part number RL-01201, which has an inductance per coil of 1.25mH, a fundamental current rating of 12A, and a maximum continuous current rating of 18A, will work. When connected for a single-phase application, the sum of the two coils will provide a total inductance of 2.5mH, or an effective impedance of 4.7%, calculated as Z = (I x 377 x L) / V, or .047 = (12 x 377 x .0025) / 240. For a 50Hz supply, modify the formulas by substitution of the factor 314 in place of 377.

SELECTION TABLE
SINGLE-PHASE MOTOR DRIVE APPLICATIONS
HP 120 V 208 V 240 V 480 V
1/6 RL-00801 RL-00401 RL-00402 RL-00202
1/4 RL-00801 RL-00401 RL-00401 RL-00202
1/3 RL-01201 RL-00401 RL-00401 RL-00201
1/2 RL-01801 RL-00801 RL-00802 RL-00403
3/4 RL-02501 RL-00801 RL-00801 RL-00402
1 RL-02501 RL-01201 RL-00801 RL-00402
1-1/2 RL-03501 RL-01201 RL-01201 RL-00803
2 RL-03501 RL-01801 RL-01201 RL-00803
3 RL-05501 RL-02501 RL-01801 RL-01202
5 RL-10001 RL-03501 RL-03501 RL-01802
7-1/2 RL-13001 RL-04501 RL-04501 RL-02502
10 RL-13001 RL-05501 RL-05501 RL-02502
15   RL-08001 RL-08001 RL-03502
20   RL-10001 RL-10001 RL-04502
25   RL-13001 RL-13001 RL-05502
30       RL-08002
40       RL-10002
50       RL-13002

These selections provide typical percent impedance rating of 5%.



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