7 Connection examples
7.3 Size 3 and 4 (41 – 200 A)
142 DS7 Soft starter 09/16 MN03901001Z-EN www.eaton.com
Figure 111: Power section, motor cascade
F3 = Superfast semiconductor fuse for type 2 coordination, in addition to Q1 (optional)
Q1 = cable protection through circuit-breaker or fuse (F1)
Q2 = Soft starter DS7
Qn1 = Contactor (1, 2, n)
Qn2 = Supply bypass contactor for motor (1, 2, n)
Qn3 = Motor protection (motor-protective circuit-breaker
or current transformer-operated overload relay)
Mn = Motor (1, 2, n)
→
The control system shown here can also be used for the DS7
soft starters in size 2 (16 to 32 A).
→
The “thermal motor protection” (Q13, Q23, Qn3) can also be
ensured with current transformer-operated overload relays
(see → section 2.11.7, “Parallel motor connection”, page 46).
Q2
L1
L2
L3
1L1
2L2
3L3
2T1
4T2
6T3
N
PE
PE
Q1
Q11
F3
Q13
M1 M2 Mn
Q12 Q21
Q23
Q22 Qn1
Qn3
Qn2
I> I> I> I> I> I>
I> I> I>
M
3 ~
M
3 ~
M
3 ~