Eaton Industrial Switchgear - xStart switching, protections and actuating motors

378 / 439

2010 CA08103002Z-EN
9/46 DM4 soft starters
Connection examples
ConnectionexamplesEngineering
In-line/in-delta connection
I I I I I I
M
3 ~
55 kW
400 V
55 kW
400 V
M
3 ~
100 A
DM4-340-55K
(105 A)
DILM115
NZMB2-S125
DILM115
NZMB2-A125
U1 V1 W1
W2 U2 V2
U1 V1 W1
W2 U2 V2
/ 690 V 400 100 / 59
55 S1 0.86 ϕ
cos kW
rpm 1410 50 Hz
A
In-Line In-Delta
100 A
3
DM4-340-30K
(59 A)
ULN 400 V
Soft starters are normally connected
directly in series with the motor (so-
called "in-line connection"). DM4
series soft starters also allow for
operation in a so-called in-delta
connection.
Advantages of an in-delta connection
in comparison to an in-line connection:
• In-delta connections are more cost-
effective, since the soft starter only
has to be designed for 58 percent
(= 1/√3) of the rated operational
current.
Disadvantagesof an in-delta connection
in comparison to an in-line connection:
• The motor must be connected with
six conductors, similar to the star-
delta connection.
• The DM4 soft starter's overload
protection is active only in one line,
so that additional motor protection
must be fitted in the parallel phase
or in the supply cable.