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Contactors for
Capacitor Switching
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Contactors for Capacitor Switching
Switching of power factor correction capacitors
WEG’s special CWMC contactors line for capacitor
switching is designed according to IEC 60947-1 and UL,
and provides the best solution for the switching of your
power factor correction capacitors.
No more in-rush
When you switch on a capacitor bank, the capacitors are
uncharged and the system sees them as a short circuit for a
quick period of time.
The in-rush current is the result of this little short circuit and
usually lasts for some milliseconds. It may reach 100 times
the rated current, being one of the main reasons for the short
life of a capacitor.
The CWMC contactor is assembled with damping resistors
which limit the high in-rush current when the capacitors are
switched on. They are assembled with and early-make
contact block, which is switched on before the main
contacts, thus, limiting the in-rush current.
However, the damping resistors don’t influence the final load,
since they are switched off after 5 milliseconds, leaving only
the capacitors in parallel with your inductive load, providing
the proper power factor correction. This process increases
the lifetime of the capacitors and also prevents net
distortions.
Iu (A) with standard contactors
Iu (A) with WEG CWMC contactor
Certifications
R
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Contactors for Capacitor Switching
www.weg.net
Modular design
For 35 mm DIN rail or
screws fixing.
Damping resistors
Avoids the high in-rush current
Contactor data and certifications
Shows all the necessary information
of the CWMC.
Early make contact block
Connect the damping resistors
and switches off after 5 ms
Auxiliary Contact
The CWMC allows the use of
standard contact blocks, the
same as used in the CWM
line, being either NO or NC.
New models
The CWMC contactors are available in 6 different models
within 4 different frames. All contactors are available with AC
coils with a large variety of voltage ranges for 50 or 60 Hz.
For DC coils and further information please check with WEG
representative.
Reactive power (kVAr)
Contactor
Thermal current Ith
(A)
Rated current AC-6b
In (A)
220-230 Vac
380-415 Vac
440 Vac
480 Vac
CWMC18-10-30**
32
21
8
15
16
17
25
CWMC25-10-30**
45
30
11
20
23
25
34
660/690 Vac
CWMC32-10-30**
60
41
15
25
30
33
45
CWMC50-10-30**
90
60
25
40
45
50
65
CWMC65-10-30**
110
77
30
50
60
65
87
CWMC80-10-30**
140
93
35
61
71
77
106
Table 1: Selection table for CWMC
** Complete with the voltage code
X06
X18
X32
X37
X42
X47
X50
24V50Hz
28V60Hz
110V50Hz
120V60Hz
220V50Hz
250V60Hz
230-240V50Hz
277V60Hz
380V50Hz
440V60Hz
400-415V50Hz
480V60Hz
440V50Hz
510V60Hz
Table 2: Voltage selection (other voltages under request)
Power Factor Correction Capacitors
WEG also provides the essential part for power factor correction, the capacitors, which are available from 220 up to
480 Vac and include:
g Single phase capacitor units from 0.83 up to 10 kVAr
g Three phase capacitor units from 0.5 up to 25 kVAr
g Power factor correction capacitors modules up to 15 kVAr (up to 60 kVAr with 4 modules in parallel)
g Power factor correction capacitors bank from 17.5 up to 75 kVAr
Contactors for Capacitor Switching
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