Danfoss VLT AHF 005 Design Guide

Example: Assume a 160 kW, 380–480 V AC drive at 25%
load at 50% speed. Illustration 10.25 shows 0.97 - rated
eciency for a 160 kW drive is 0.98. The actual eciency is
then: 0.97x 0.98=0.95.
Eciency of the motor (η
MOTOR
)
The eciency of a motor connected to the drive depends
on magnetizing level. In general, the eciency is as good
as with mains operation. The eciency of the motor
depends on the type of motor.
In the range of 75–100% of the rated torque, the eciency
of the motor is practically constant, both when the drive
controls it and when it runs directly on the mains.
In small motors, the inuence from the U/f characteristic
on eciency is marginal. However, in motors from 11 kW
(15 hp) and up, the advantages are signicant.
Typically the switching frequency does not aect the
eciency of small motors. Motors from 11 kW (15 hp) and
up have their eciency improved (1–2%) because the
shape of the motor current sine-wave is almost perfect at
high switching frequency.
Eciency of the system (η
SYSTEM
)
To calculate system eciency, the eciency of the drive
(η
VLT
) is multiplied by the eciency of the motor (η
MOTOR
):
η
SYSTEM
=η
VLT
x η
MOTOR
10.13
Acoustic Noise
The acoustic noise from the drive comes from 3 sources:
•
DC link coils.
•
Internal fans.
•
RFI lter choke.
Table 10.36 lists the typical acoustic noise values measured
at a distance of 1 m (9 ft) from the unit.
Enclosure size dBA at full fan speed
E1–E2
1)
74
E1–E2
2)
83
F1–F4 and F8–F13 80
Table 10.36 Acoustic Noise
1) P450–P500, 525–690 V only.
2) All other enclosure E models.
Test results performed according to ISO 3744 for audible
noise magnitude in a controlled environment. Noise tone
has been quantied for engineering data record of
hardware performance per ISO 1996-2 Annex D.
10.14 dU/dt Conditions
NOTICE
To avoid the premature aging of motors that are not
designed to be used with drives, such as those motors
without phase insulation paper or other insulation
reinforcement, Danfoss strongly recommends a dU/dt
lter or a sine-wave lter tted on the output of the
drive. For further information about dU/dt and sine-wave
lters, see the Output Filters Design Guide.
When a transistor in the inverter bridge switches, the
voltage across the motor increases by a dU/dt ratio
depending on:
•
The motor cable (type, cross-section, length
shielded or unshielded).
•
Inductance.
The natural induction causes an overshoot U
PEAK
in the
motor voltage before it stabilizes itself at a level
depending on the voltage in the DC link. The rise time and
the peak voltage U
PEAK
aect the service life of the motor.
In particular, motors without phase coil insulation are
aected if the peak voltage is too high. Motor cable length
aects the rise time and peak voltage. For example, if the
motor cable is short (a few meters), the rise time and peak
voltage are lower. If the motor cable is long (100 m (328
ft)), the rise time and peak voltage are higher.
The switching of the IGBTs causes the peak voltage on the
motor terminals. The drive complies with the demands of
IEC 60034-25 regarding motors designed to be controlled
by drives. The drive also complies with IEC 60034-17
regarding normal motors controlled by drives.
High-power range
The power sizes in Table 10.37 and Table 10.38 at the
appropriate mains voltages comply with the requirements
of IEC 60034-17 regarding normal motors controlled by
drives, IEC 60034-25 regarding motors designed to be
controlled by drives, and NEMA MG 1-1998 Part 31.4.4.2 for
inverter-fed motors. The power sizes in Table 10.37 and
Table 10.38 do not comply with NEMA MG 1-1998 Part
30.2.2.8 for general-purpose motors.
Electrical Installation Con...
VLT
®
HVAC Drive FC 102
190 Danfoss A/S © 11/2017 All rights reserved. MG16C302
1010

Danfoss VLT AHF 005 Specifications

General

Brand	Danfoss
Model	VLT AHF 005
Category	DC Drives
Language	English