Danfoss VLT FC 102 Series Design Manual page 39

Introduction to VLT® HVAC D...
2.8.3 PM/EC+ Motor Control
The Danfoss EC+ concept provides the possibility for using
high efficient PM motors in IEC standard enclosure types
operated by Danfoss adjustable frequency drives.
The commissioning procedure is comparable to the
existing one for asynchronous (induction) motors by
utilizing the Danfoss VVC plus PM control strategy.
Customer advantages:
•
Free choice of motor technology (permanent
magnet or induction motor)
•
Installation and operation as known for induction
motors
•
Manufacturer independent when choosing system
components (e.g., motors)
•
Best system efficiency by choosing best
components
•
Possible retrofit of existing installations
•
Power range: 1.5–30 hp [1.1–22 kW]
Current limitations:
•
Currently only supported up to 30 hp [22 kW]
•
Currently limited to non-salient type PM motors
•
LC filters not supported together with PM motors
•
Over Voltage Control algorithm is not supported
with PM motors
•
Kinetic backup algorithm is not supported with
PM motors
•
AMA algorithm is not supported with PM motors
•
No missing motor phase detection
•
No stall detection
•
No ETR function
MG11BC22
Design Guide
2.8.4 Sizing of Adjustable Frequency Drive
and PM motor
The low motor inductances of PM motors can cause
current ripples in the adjustable frequency drive.
To select the right adjustable frequency drive for a given
PM motor, ensure that:
•
•
•
The current (A) and the typical power rating (kW) for a PM
motor can be found in chapter 9.1 Line Power Supply Tables
for different voltages.
Danfoss A/S © Rev. 06/2014 All rights reserved.
The adjustable frequency drive can deliver the
required power and current in all operating
conditions.
The power rating of the adjustable frequency
drive is equal to or higher than the power rating
of the motor.
Size the adjustable frequency drive for a constant
100% operating load with sufficient safety
margin.
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