Lovato DCRG8 Automatic Power Factor Controller 8 Steps

An 8-step power factor controller built for capacitor bank panels

The Lovato DCRG8 is an automatic power factor controller that switches capacitor steps in and out to hold a target power factor on an industrial supply. It has eight relay outputs, a backlit 128 x 80 pixel graphic LCD, true RMS measurement and a 144 x 144 mm flush-mount case with IP65 front protection. The same family includes the DCRG8F for dynamic (static output) correction and the DCRG8IND for capacitive reactive power correction, so a project can stay with one controller platform.

Where a plant draws a lot of inductive load (motors, compressors, pumps, welding sets, transformers), a capacitor bank with an automatic controller keeps the reactive demand down and the power factor close to the utility or site requirement. The DCRG8 reads the voltage and a 5 A (or programmable 1 A) current transformer signal, calculates the optimum combination of steps and operates the contactors in the capacitor bank.

Technical specifications

What the controller does and how to size it

Besides stepping capacitors, the DCRG8 measures the installed reactive power of each step, counts operations per step and balances wear across steps of equal size, which extends contactor life. It includes capacitor overcurrent protection on all three phases, panel over-temperature protection with an internal and an optional external NTC01 sensor, harmonic analysis of current and voltage, and a quick CT programming routine. The manual lists a TEST mode that lets the installer operate the relays by hand during commissioning.

Master-slave operation allows one DCRG8 to command up to eight slave controllers when the correction system is split across several panels. Independent correction for each single phase (SPPFC) is available, and the controller can work with medium-voltage lines through voltage transformers. For dynamic correction on fast-changing loads, Lovato offers the DCRG8F with static outputs, and the DCRG8 can be combined with the EXP1001 static-output module.

Selection and ordering checklist

Confirm the number and size of capacitor steps, the CT ratio and secondary (5 A or 1 A), the supply voltage for the controller, and whether harmonic distortion calls for detuned reactors; the controller can operate in systems with high harmonic content, but the capacitor bank design remains the engineer’s responsibility. Choose EXP modules for extra steps (EXP1006, EXP1007), inputs and outputs, communication (RS485, Ethernet, Profibus-DP, GSM) and data logging, and check that the controller and modules fit within the maximum expandability table in the catalogue. Lovato also lists contactors for power factor correction duty in its contactor section.

Documents and quotation

The attached instruction manual (I340) covers the DCRG8 and DCRG8IND display pages, parameter tables, alarm list, master-slave and single-phase configurations, wiring and mechanical drawings. The catalogue chapter holds the ordering table for expansion modules. When requesting a quotation for the DCRG8, send the number of steps, the CT details, the supply voltage and any communication or expansion modules required. See also Automation Accessories and the Lovato Lovato DMED300T2 three-phase energy meter.