RCG-2AC Current comparator relay for protection of synchronous motors

Current comparator relay for the protection of synchronous motors

He RCG-2AC current comparator relay It has been designed to protect systems where two AC motors must operate synchronously. The device continuously compares the current drawn by both drives using two current transformers (CTs) and detects anomalous differences that may indicate mechanical blockages, overloads, misalignments or failures in one of the motors.

Continuous monitoring of both drives allows the installation to be stopped before a load difference causes structural deformation, damage to gearboxes, cable breakage, or malfunctions in the lifting mechanisms. Therefore, this current comparator relay it is especially suitable for overhead cranes, gantry cranes, double drive hoists, suspended platforms for building cleaning (BMU) and any industrial machinery equipped with synchronized motors.

How does a current comparator relay work?

The equipment receives signals from two current transformers, installed one in each motor. From these signals, it continuously compares the relative difference between both currents and, when the imbalance exceeds the threshold set by the user, it activates a Fail-Safe safety relay which allows the installation to be stopped safely.

Internal timing filters out transient current spikes during start-ups, maneuvers, or load changes, preventing unexpected tripping and ensuring reliable monitoring of synchronized motors.

Main advantages

• Protection of synchronized motors by current comparison.
• Early detection of mechanical blockages, misalignments and drive failures.
• Compatible with 5A or 15A current transformers.
• Safety relay Fail-Safe with alarm for power failure, sensors or the equipment itself.
• Universal power supply 24…240 VAC/DC.
• Galvanic isolation between inputs, output and power supply.
• Compact design 17.5 mm for DIN rail mounting.
• Plug-in terminals for quick and safe installation.

Common applications

• Overhead cranes.
• Gantry cranes.
• Motorized end caps.
• Double drive hoists.
• Building Cleaning Units (BMUs).
• Synchronized winches.
• Conveyors and belts with double drive.
• Industrial lifting systems.
• Special machinery with synchronized motors.

Why use a current comparator relay?

In facilities with two synchronized engines, A difference in load between the two drives can generate excessive mechanical stress, torsional stress in the structure, and premature wear of gearboxes, cables, or transmission mechanisms. current comparator relay It continuously monitors the consumption of both motors and generates an alarm signal when it detects an imbalance higher than the configured value.

This solution increases the safety of the installation, reduces maintenance costs, and helps to avoid costly breakdowns. overhead cranes, hoists, lifting systems and other industrial applications with dual drive.