###### Asked in Electronics Engineering

Electronics Engineering

# How do you calculate mH value for line reactor?

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## Related Questions

###### Asked in Job Interviews, Nuclear Energy, iPod Touch, Nuclear Reactors

### What is an input reactor?

Just like a line reactor..
A 3-phase Line Reactor is a set of three (3) coils (also known
as windings, chokes or inductors) in one assembly. It is a series
device, which means it is connected in the supply line such that
all line current flows through the reactor, as shown below. Line
Reactors are current-limiting devices and oppose rapid changes in
current because of their impedance. They hold down any spikes of
current and limit any peak currents. This resistance to change is
measured in ohms as the Line Reactor's AC impedance (XL) and is
calculated as follows: XL = 2 π f L (ohms), where: f = frequency in
hertz (cycles per second) harmonic frequency examples: harmonic (60
Hz)frequency (Hz)5th3007th42011th660 L = reactor inductance in
henries (H), millihenries (mH) -- H x 10-3, microhenries (µH) -- H
x 10-6 By inspection of the XL formula, the Line Reactor is
directly proportional to the frequency (f) and the inductance (L).
That is, if the impedance of a Line Reactor is 10 ohms at 60 Hz,
then at the 5th harmonic (300 Hz) the impedance is 50 ohms. If the
inductance (L) is increased, then the impedance will increase
proportionally. This increase in Line Reactor impedance will reduce
the current in the line. The higher the frequency (Hertz), the
lower the current. A Line Reactor's DC resistance (R-ohms) is very
low by design so that the power losses (watts-I2R) are low. Line
Reactors are rated by % impedance, voltage and current. However,
they are sized by % impedance, voltage and motor horsepower. The
motor horsepower determines the necessary current rating for the
Line Reactor. Line Reactors are rated by impedance, voltage and
current. # Impedance (% impedance of load Z)
The load impedance (Z) is calculated by this formula:
Z = V/I, where Z = load impedance (ohms), V = line voltage
(volts), and I = line current (amps)
This percent of load impedance also determines the voltage drop
across the Line Reactor. For example, a 5% Line Reactor would have
a 5% voltage drop. # Voltage rating
Since a Line Reactor is a current-sensitive device, the voltage
rating is needed for dielectric concerns as a maximum voltage and
horsepower. It is also used to determine the current rating when
given only voltage and horsepower. # Current rating (amperes)
This is the current required by the load(s). It is total current
flowing to the load(s) and through the reactor. This current is
measured in amperes (amps).

###### Asked in US Army

### What helicopter does the US army use?

Several.
OH-6 Cayuse, MH-6 "Little Bird", and other variants of the H-6
series
OH-58 Kiowa
AH-1 Cobra (still in service with some second line units)
AH-64 Apache
UH-60 Blackhawk, MH-60, and other variants of the H-60
series
CH-47 Chinook, MH-47, and other variants of the H-47
series
On a side note, the Army is the only branch which operates the
H-47 series (CH-47, MH-47, etc.) and the only branch which does NOT
operate the H-53 series (CH-53, MH-53, etc.)

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