How to Wire the MTE RL Series Three-Phase Line Reactor to a Variable Frequency Drive

How to Wire the MTE RL Series Three-Phase Line Reactor to a Variable Frequency Drive


Welcome to G-TV! Today I will be showing you
how to wire the MTE’s RL Series three phase reactor to a variable frequency drive, also
called a VFD, and how it helps reduce the harmonics that are produced by the VFD. Wiring,
installation and troubleshooting of electronic components, such as drives and reactors, should
only be performed by a qualified electrician after the power has been turn off and the
disconnect has been locked out to prevent unintended energizing. For the demonstration
we have today, I have an MTE RL series reactor, a Fluke 43 Power Quality Analyzer, a VFD and
a motor. For the first test, with the power turned off, I will connect the incoming power
wires to the VFDs input terminals. I can then connect the Fluke meter’s red and black
test leads to two of the three input terminals on the VFD. I will put the current clamp from
the Fluke meter around one of the incoming power wires. This will allow the Fluke to
give an accurate reading of the harmonics being produced by the VFD. I will now apply
power to the VFD, start it and run the motor up to full speed. For the demonstration, a
load has been connected to the motor. Taking a look at the Fluke meter, I can see the THD
or Total Harmonic Distortion is about 53%. I will now stop the VFD and turn off the power.
I will wait a few minutes to allow the bus capacitors to discharge before touching any
of the power connections on the VFD. I can disconnect the VFD input power wires from
the power source and connect them to the output side of the reactor, marked A2, B2 and C2.
I will connect the input side of reactor, marked A1, B1 and C1 to the power source.
I will also connect the Fluke meter’s red and black test leads to two of the three input
terminals on the reactor and then put the current clamp around one of the incoming power
wires. I will apply power to the VFD, start it and run the motor up to full speed. Taking
a look at the Fluke meter, I can see that with the reactor in place the THD has dropped
to 24.7%. The amount of harmonic reduction will vary depending motor load and application.
Using a 3 phase reactor to reduce the harmonics produced by the VFD, may help prevent problems
with sensitive equipment that is on the same power feed as the VFD. The reactor also provides
a degree of protection to the VFD from power surges. MTE’s RL Series Reactors, along
with thousands of other products and services are available at Galco.com.

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