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%.
|