Product Overview

The Allen-Bradley 1407-CGCM​ is a Combination Generator Control Module — CGCM for short — that consolidates four functions normally spread across separate devices into one compact, panel-mounted unit. Instead of buying a voltage regulator, a synchronizer, a protection relay and a metering package, and then wiring them together, an engineer using the Allen-Bradley 1407-CGCM​ gets excitation control, generator protection, breaker synchronisation and full-featured metering in a single module that talks natively to a ControlLogix controller. Rockwell Automation markets it under the Allen-Bradley brand; the hardware itself is manufactured by Basler Electric, a long-established name in excitation and generator control.Functionally, the Allen-Bradley 1407-CGCM​ sits between the generator and the plant control system. It senses three-phase generator voltage and current plus bus voltage, drives the exciter field through a pulse-width-modulated power stage, and closes its regulation loop around whichever mode the application demands: automatic voltage regulation (AVR), manual field current regulation (FCR), power factor control (PF) or reactive power control (VAR). At the same time it evaluates synchronising conditions — frequency, phase rotation, phase angle and voltage magnitude — across one or two breakers, and supervises the machine with a protective function set covering over/under voltage, over/under frequency, reverse power, loss of excitation, V/Hz and voltage-restrained overcurrent.The value of the Allen-Bradley 1407-CGCM​ is architectural. Fast regulation and synchronising are processed locally in the module, while metering, alarms and status flow over ControlNet to the Logix processor for plant-level logic, so the control loop never depends on PLC scan time. Because it supports redundant pairs with auto-tracking and automatic transfer, it is equally at home in a single standby genset and in a multi-machine paralleling switchgear lineup. Rockwell lists the product as discontinued as of 31 December 2023, which makes it a life-cycle spare for existing installations.

Technical Specifications

Main Features and Advantages

Four regulation modes with bumpless auto-tracking: The Allen-Bradley 1407-CGCM​ does not force you into one control philosophy. AVR holds terminal voltage for normal service, FCR gives the operator direct field current control for commissioning and exciter testing, PF mode holds a set power factor against a utility tie, and VAR mode controls reactive output directly. Auto-tracking between operating modes means the standby mode continuously follows the active one, so switching is smooth rather than a step change that disturbs the machine or the bus.Limiters that protect the machine, not just the process: Over-excitation limiting (OEL) and under-excitation limiting (UEL) operate in AVR, VAR and PF modes, preventing the exciter from overheating during field forcing or the generator from slipping out of stability while absorbing reactive power. Underfrequency V/Hz compensation protects the generator and connected transformers during speed excursions, and line drop compensation allows voltage to be regulated at a remote point rather than at the terminals.Synchronising and load sharing built in: The Allen-Bradley 1407-CGCM​ performs sync check across one or two breakers, evaluating frequency, phase rotation, phase angle and voltage magnitude, including dead-bus closing windows. Once paralleled, reactive load sharing is handled through droop compensation or cross-current (reactive differential) compensation, while real power load sharing is implemented with the module’s load share line, avoiding the circulating reactive current that plagues poorly matched machines.Metering that replaces a separate package: Voltage, current, frequency, real and reactive power, power factor, phase angle, field voltage and current, and energy values are all metered to 0.2% class accuracy and exposed to the Logix controller as floating-point tags. Soft-start voltage buildup with an adjustable ramp limits inrush at startup, and a rotating diode monitor detects open or shorted diodes on brushless exciters before they cause a forced outage.Designed for redundancy: In a redundant pair, the Allen-Bradley 1407-CGCM​ units exchange data over a dedicated RS-232 link so the backup tracks the active unit continuously and takes over automatically if the primary fails — a decisive feature where generation availability is contractual.