Internal Drive Operation; Introduction; Description Of Operation - Danfoss VLT FC Series Service Manual

Internal Drive Operation

5 Internal Drive Operation

5.1 Introduction

This section is intended to provide an operational overview
of the main assemblies and circuitry of a drive. With this
information, a repair technician can better understand the
operation of the drive and the troubleshooting process.

5.2 Description of Operation

5 5
A drive is an electronic controller that supplies a regulated
amount of AC power to a 3-phase asynchronous motor. By
supplying variable frequency and voltage to the motor, the
drive controls the motor speed. It can also maintain a
constant speed as the load on the motor changes. The
drive can also stop and start a motor without the
mechanical stress associated with a line start.
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VLT FC Series, D1h–D8h, Da2/Db2/Da4/Db4, E1h–E4h, J8/J9
In its basic form, the drive can be divided into the
following 4 main areas:
•
•
•
•
See Illustration 5.1 for details.
Within those areas, components are grouped into 3
sections:
•
•
•
These areas and components are covered in greater detail
in chapter 5.3 Sequence of Operation.
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Rectifier
DC link (DC bus)
Inverter
Control
Control logic section
Logic-to-power interface
Power section
MG94A502