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Detuned Capacitor Banks

NUCO Controls designs and manufactures fixed and automatic detuned capacitor banks providing power factor correction safely in a harmonic environment. Our detuned capacitor banks are available in the following configurations:

  • 240-600VAC, 3PH
  • NEMA 1, 12, or 3R
  • MLO (Main Lug Only) or Circuit Breaker for Incoming Connections
  • 7% Tuning Reactors (3.78th harmonic)

NUCO’s detuned banks are manufactured using the latest technology for all components including the power factor controller, contactors, capacitors and reactors.

NUCO’s detuned capacitor banks are designed to operate in most harmonic environments that contain up to 7% voltage distortion. NUCO is available to assist you to ensure the proper solution is developed.

When IEEE 519 is required, NUCO is available to assist in developing a solution utilizing active filters, detuned capacitor banks, or a combination of the two. Please contact us for additional information.

Detuned Capacitor Bank Solutions

Power Factor Controller (For Automatic Detuned Capacitor Banks)

NUCO utilizes an innovative touch screen power factor controller that features a full graphical display. It provides the following information:

  • Inductive/Capacitive power factor
  • Active outputs
  • Demand for switching capacitor steps on/off
  • Alarm conditions
  • Over-temperature condition
  • Phase shift
  • C/k
  • Number of outputs
  • Type of switching sequence
  • Alarm
  • Voltage, Current
  • Harmonic voltage and current distortion levels
  • Bar graph of current and voltage individual harmonics up to the 49th harmonic
Additional Features:
  • Programmable protection thresholds for under-voltage, over-temperature, and excessive harmonic distortion
  • Intuitive, easy-to-use guided navigation and programming
  • Multi-language support
  • Built-in software help guide
  • Input for both daytime and nighttime power factor correction targets
  • External alarm input
  • Output contacts for alarm and fan relays
  • Backlit display
  • Optional RS-485 Modbus adapter
  • Real-time clock to provide time and date stamps for alarms and events


Capacitor elements utilized by NUCO in automatic capacitor systems incorporate unique and exclusive triple safety features, including segmented capacitor film with traditional self-healing features.

The capacitor elements also incorporate true three-phase over-pressure disconnect to safely isolate the capacitor at the end of its lifetime, or when the capacitor experiences severe overload. Most competing capacitor products only provide two-phase disconnection. NUCO’s automatic capacitor systems are the safer, more reliable solution.

Capacitor elements are compliant with the following standards:

  • UL 810
  • CSA C22.2 No. 190
  • IEC 60831

Click here to see all the benefits of the capacitor elements used by NUCO Controls.

Tuning Reactors

When harmonic levels become too high in the electrical system, tuning reactors may be required. NUCO incorporates high-quality reactors manufactured by leading suppliers who are backed by more than 70 years of experience in the field.

Our reactors use an exclusive PolyGap core construction. This innovative reactor design is constructed from many tiny air gaps rather than the conventional method of using a mere single or double air gap construction. The advantage is threefold: minimized power losses, reduced audible noise, and stray magnetic fields outside of the reactor are virtually eliminated.

In order to ensure precisely controlled tuning, NUCO’s reactors are manufactured with a ±3% tolerance.


NUCO provides contactors which are specifically designed for capacitive switching applications. When specified, custom contactors include a damping resistor to minimize the effects of peak capacitive switching currents and to maximize the life of your equipment.

Advantages of NUCO’s contactor solutions include:

  • Significant damping of in-rush current.
  • Improvement of the voltage quality during the switching process.
  • Increased contactor service life.
  • Extremely high operational reliability of the automatic capacitor bank system.
  • Extended maintenance intervals.

Fixed Reactor Bank Matrix

Automatic Reactor Bank Matrix

  1. Part numbers shown are base part numbers:  480V, Enclosure Type 1, Main Lugs Only, No Options.
  2. For additional options, see part number configurator below or contact NUCO.

NUCO also provides custom solutions to fit your needs. Please contact us for non-standard configurations.

Automatic Reactor Bank Matrix