All types of 3-phase asynchronous standard motors can be
connected to a frequency converter. Normally, small
motors are star-connected (230/400 V, Δ/Y). Large motors
are delta-connected (400/690 V, Δ/Y). The correct
connection mode and voltage can be read from the motor
nameplate.
No.
96
97
98
Motor voltage 0-100% of mains
voltage.
U
V
W
3 wires out of motor
U1
W2
V1
U2
W1
V2
6 wires out of motor, Delta
connected
U1
V1
W1
6 wires out of motor, Star
connected
Interconnect U2, V2, W2 separately
(optional terminal block)
No.
PE
Ground connection
Table 3.6 Motor Connection
CAUTION
In motors without phase insulation paper, an LC filter
should be fitted on the output of the frequency
converter.
U
1
V
1
W
1
175ZA114.11
96
97
98
96
97
98
FC
FC
Motor
Motor
U
2
V
2
W
2
U
1
V
1
W
1
U
2
V
2
W
2
Illustration 3.27 Motor Connection
Mains supply isolated from ground
If the frequency converter is supplied from an isolated
mains source ( IT mains) or TT/TN-S mains with grounded
leg, turn off the RFI switch. For further reference, see IEC
364-3. If optimum EMC performance is needed, parallel
motors are connected or the motor cable length is above
25 m, set the switch in ON position.
In OFF position, the internal RFI capacities (filter capacitors)
between the chassis and the intermediate circuit are cut
off to avoid damage to the intermediate circuit and to
reduce the ground capacity currents (according to IEC
61800-3).
Also refer to the application note
VLT on IT mains
. It is
important to use isolation monitors that are capable for
use together with power electronics (IEC 61557-8).
NOTICE
The RFI switch is not to be operated with mains
connected to the unit. Check that the mains supply has
been disconnected before operating the RFI switch.
The RFI switch disconnects the capacitors galvanically
from ground.
Remove the switch Mk9 placed next to terminal 96, to
disconnect the RFI-filter.
3.4.5 Direction of Motor Rotation
175HA036.11
U
1
V
1
W
1
96
97
98
FC
Motor
U
2
V
2
W
2
U
1
V
1
W
1
96
97
98
FC
Motor
U
2
V
2
W
2
Illustration 3.28 Switch 2 Phases on the Motor Terminals
The factory setting is for clockwise rotation with the
frequency converter transformer output connected as
follows:
•
Terminal 96 connected to U-phase.
•
Terminal 97 connected to V-phase.
•
Terminal 98 connected to W-phase.
The direction of rotation can be changed by switching 2
phases on the motor terminals.
Installation
Design Guide
MG27E402
Danfoss A/S © Rev. May/2014 All rights reserved.
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