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M-AI-VT-001-EN Rev.C.1
M-AI-VT-001-EN Rev.C.1
Overview of the VTT Compressor
Component
Definition
Remarks
RFI Filter
Device to suppress radio frequency interference (RFI).
Optional
Control Card
Input/output communication and control board.
Standard
Power Card
Supplies power to the internal components.
Standard
Mains Input
Three-phase AC power supply to the adjustable frequency drive module.
Standard
Rectifier
The rectifier bridge converts the AC input to DC current to supply
inverter power.
Standard
DC Bus
Intermediate DC bus circuit to handle DC power.
Standard
DC reactors
• Filters the immediate DC circuit voltage
• Provides line transient protection
• Reduces Root-Mean-Square (RMS) current
• Raises the power factor reflected back to the line
• Reduces harmonics on the AC input
Standard
Capacitor bank
• Stores the DC power
• Provides ride-through protection against short power losses
Standard
Inverter
Converts DC into a controlled PWM AC waveform for a controlled variable
output to the motor.
Standard
Control circuitry Input power, internal processing, output, and motor current are monitored
to provide efficient operation and control.
Standard
Back channel
The back channel provides additional protection in corrosive environments,
such as salt air found near sea side applications.
Standard
Table 2
Interior Components
Descriptions
Thermal Memory
Retention Compliance
Safety Precautions
The Drive Module complies with UL508C thermal
memory retention requirements.
Drive Modules contain high-voltage components
that if handled improperly can result in fatal
injury. Only trained technicians should install and
operate the equipment. No repair work should be
attempted without first disconnecting power to
the drive module and waiting for stored electrical
energy to discharge, a minimum of 20 minutes.
Strict adherence to safety precautions and
notices is mandatory for safe operation of the
drive module.
• • • WARNING • • •
Discharge Time
Drive Modules contain DC-link capacitors that can remain charged even when the drive module is not powered.
To avoid electrical hazards, disconnect the following:
• AC mains
• Remote DC-link power supplies, including battery backups, uninterruptible power supply (UPS) and DC-link
connections to other drive modules.
Wait 20 minutes for the capacitors to fully discharge before performing any service or repair work.