The Circutor CMC 32 B (code R281A8) is a capacitor-switching contactor from the CMC-B series, designed for connecting and disconnecting single-step or multi-step capacitor banks in reactive power compensation systems. It carries a nominal operating current of 37 A at 400 V and delivers up to 25 kvar at 400-480 V, making it well suited for medium-capacity power factor correction installations across a wide supply voltage range of 220 to 690 V.

Technical specifications:

• Model: CMC 32 B
• Circutor code: R281A8
• EAN: 8433059202866
• Frequency: 50/60 Hz
• Nominal voltage: 220 … 690 V
• Nominal operating current: 37 A (at 400 V)
• Coil voltage: 230 V AC (tolerance: 0.85 … 1.1 Un)
• Maximum operating capacity: 14 kvar (220-240 V), 25 kvar (400-440-480 V), 30 kvar (500-550 V), 35 kvar (660-690 V)
• Dumping resistors: 1
• Switching rate: 100 operations/h
• Electrical lifetime: 200 000 cycles
• Insulation voltage: 690 … 1000 V
• Dimensions (W x H x D): 54.6 x 80 x 121.4 mm
• Weight: 0.473 kg
• Protection class: IP 00
• Operating temperature: -25 … +55 C
• Relative humidity: 5 … 95% (without condensation)
• Standards: IEC 60947-4-1, VDE 0660

Features and benefits:

• One built-in dumping resistor suppresses inrush current each time a capacitor step is energised, limiting contact stress and extending service life.
• An electrical lifetime of 200 000 switching cycles ensures long-term reliability in installations where capacitor steps operate continuously.
• Broad voltage compatibility from 220 V to 690 V covers most low-voltage distribution networks without requiring alternative variants.
• A switching cadence of up to 100 operations per hour accommodates fast-reacting automatic power factor correction controllers in dynamic load environments.
• Operating temperature range of -25 … +55 C permits installation in demanding ambient conditions inside switchgear panels and enclosures.

Applications:

• Switching individual capacitor steps in automatic power factor correction banks.
• Multi-step reactive power compensation panels in industrial plants and manufacturing facilities.
• Capacitor bank control in commercial buildings and large office complexes with variable reactive loads.
• Low-voltage distribution networks requiring active reactive power management.

Also known as: Circutor CMC 32 B, CMC 32 B R281A8, R281A8 capacitor contactor, capacitor switching contactor, power factor correction contactor.