Page 15 - Motor protection and control Manual motor starters, contactors and overload relays

ABB MOTOR PROTECTION AND CONTROL 1/13
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UA and UA..RA contactors

For capacitor switching up to 80 kvar

Safely switch your capacitor banks without contacts welding
ABB offers the widest contactor range on the market for the capacitor switching

demanding application. UA..RA contactors with damping resistors, are used when
inrush peak currents are far exceeding 100 times. UA contactors is a simple solution
used when peak currents are less or equal to 100 times nominal rms current.

Power factor correction
Industrial sites have low power efficiency due to motor
winding inductances. Capacitor bank panels are added for
power factor correction.
An automatic power factor correction system consists of
several capacitor banks of identical or different ratings (sev-
eral steps), energized separately according to the value of
the power factor to be corrected.

The inrush current peak, in the case of automatic correction,
depends on the power of the steps already on duty, and can
reach 100 times the nominal current of the step to be ener-
gized.

Switching capacitors banks with standard contactors may
cause electrical damages like contact welding, coil burning
or even fire on the installation.

ABB provides a choice of contactors dedicated for capacitor
switching applications and CAPCAL a selection tool, avail-
able on the ABB Website:

https://new.abb.com/low-voltage/products/motor-protec-
tion/contactors-for-capacitor-switching

Current
Transformer

Loads
Power Transformer

Main Automatic capacitors bank
Control Circuit with reactors
Transformer Breaker

Bk
Outputs
FU-1 FU-2 FU-3 FU-11 FU-12
RVT
P.F.C
C1 C2 C3 C11 R11 C12
R1 R2 R3 R12

Temp. Capacitor Capacitor Capacitor Capacitor Capacitor 1SBC100214C0202_page com
#11
#3
#1
Probe Fan(s) #2 #12