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MSD Manual
Product Description
The MotorShield™ is a 3-phase low-pass sine wave filter designed and developed by TCI to
deliver conditioned power to motor loads driven by PWM drives with switching frequencies from 2
kHz to 16 kHz. Any drive control parameter which has the effect of reducing the carrier or
switching frequency below 2 kHz at any time must be disabled. Some sine wave or long lead
mode drive parameters or operating modes can have this effect. This filter is suitable for VFD
drives configured to Volts per Hz modes only. Available for three phase voltage systems up to
460/480 Volts, the MotorShield™ is a passive LC filter connected in series with the output
terminals of the variable frequency drive. This design removes the carrier frequency distortion
from the output voltage waveform resulting in a nearly pure sine wave voltage profile.
The MotorShield™ sine wave filter reduces the effects of the reflected wave phenomenon (dV/dt),
which can cause motor heating, insulation damage, and excessive audible noise. The reduction
of high frequency VFD output currents extends the life of motors and transformers and eliminates
the need for special motor cables. The MotorShield™ reduces VFD ground fault problems and
noise interference in transducer signals caused by stray high frequency harmonic currents.
The MotorShield™ is available in a UL Open Type and Type 1 and Type 3R enclosures which
can be mounted adjacent to the VFD.
The MotorShield™ consists of the following standard features and components:
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An L-C power filter circuit with:
A TCI 3-phase reactor
High-endurance, harmonic-rated capacitors
Compression terminals for ease and integrity of all power wiring
Thermal switches on reactor and capacitor
Suitable for all lead lengths extending up to 15,000 feet
5
2.0 General Information
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