Carlo Gavazzi energy meters

Current, Voltage and Phase Monitoring Devices

CARLO GAVAZZI is a market leader in devices for monitoring phase loss, incorrect phase sequence, phase unbalance, over/under current, earth leakage, over/under load, over/under frequency, and over/under voltage with one of the broadest range of products in the industry. With over 40 years of experience, Carlo Gavazzi knows what it takes to manufacture monitoring relays that are designed to withstand the rigors of your toughest applications. With local sales and support centers located in 22 countries and independent distribution in over 100 countries, CARLO GAVAZZI product and technical support is available around the world.

CARLO GAVAZZI's monitoring relays are used in various applications to protect equipment, machinery and people from dangerous situations. Examples include motors, elevators, compressors, pumps, air conditioning systems, mixing tanks, etc. Our product range covers most automation industry requirements, single and three-phase, current, motor management, earth leakage (ground faults), frequency, temperature and pump management. Process signals can also be monitored (4-20mA, 0-10V) for machinery operation verification. Monitoring relays are stand alone, acting as an independent watchdog, and can be installed by an electrician. Event-based outputs can be used to trigger relays or alarms, or as inputs to Programmable Logic Controllers (PLC).

CARLO GAVAZZI offers, as part of our monitoring controls family, a comprehensive range of products for the following:

Why Monitor Current, Voltage and Phase?

There are a broad range of applications for current, voltage and phase monitoring products but the major application is for motor protection.

When a phase is lost due to a fuse or a line failure, the motor will be powered from only 2 lines and if running may continue to run or it may stall drawing excessive current and ultimately failing. If you attempt to start the motor it will likely not start and again will draw excessive current and fail. Even if a phase isn't lost, it is not uncommon, due to distribution of loads, to have a voltage asymmetry - which means that all 3 phase voltages are not equal. Just a 5% voltage asymmetry results in an up to 50% rise in motor temperature. A phase loss/asymmetry monitor and over-load monitor is a small investment to ensure the life and reliability of a motor.

Motors are expensive, difficult to replace and the service technician probably won't have a replacement in his service van. Don't turn what should just be a fuse replacement into a major disruptive shut-down.

We have prepared a useful guide for selecting a monitoring device to protect your machinery. This covers the basics of what needs monitoring as well as well as the consequences of not properly protecting your electrical equipment. Tech Tips for Selecting a Monitoring Device

Online Training

We have created an Online Training Course for our Monitoring Relays consisting of 4 modules. These modules cover the technical aspects of current, voltage, phase and frequency monitoring. In addition it also covers the applications and markets where these products are used.

Our Product Range



HVAC systems rely on the correct power being applied - both under and over-voltage can be a problem. In addition it is critical that compressors be monitored for phase loss in the event a fuse blows or a line is down. Otherwise, this will cause the compressor to fail quickly.

Ventilation fans can also be monitored for over/under current or power as a means to determine if a fan belt is broken or slipping, or if an air filter is clogged.

White Paper on Critical Load Monitoring

Lifts and Escalators

With lifts and escalators it is critical that the direction of rotation of the motor is correct, otherwise, the elevator will go in the wrong direction. A phase sequence monitor is an important control device to ensure that the motor turns in the correct direction.

In additon to phase sequence monitoring, our braod range of phase loss monitors, motor winding temperature monitors, current monitoring relays, magnetic sensors and safety relays ensure the protection and safety of the elevator.

Water Treatment and Pumping Stations

In addition to the damaging effects of phase loss, over/under voltage and over load, it is also important to be able to monitor the temperature of the motor windings to prevent damage to a motor. We offer monitoring relays which connect to PTC (positive temperature coefficient) sensors imbedded in the motor windings.

Another common practice is to have redundancy in pumps. When the pump needs to be on, it will alternate between pumps on subsequent starts. In addition if one pump is on for more than 6 hours, it will automatically switch pumps. This prevents one pump from being used continuously. We offer pump alternating relays for 2 or 3 pump systems.

White Paper on Critical Load Monitoring

Critical Load Monitoring
EV Charging

Critical load monitoring refers to any load, which if it fails, causes a significant loss in production, equipment downtime time, or cost to repair or replace equipment.

A phase loss, over/under voltage, over/under load monitor is a good investment to extend the life of equipment. It is also common to install compact, line powered current monitors (Go/No Go switches) to verify that equimpent that should be operating, is actually operating. This includes cooling fans, water circulation pumps, and other critical loads.

Training VideoWhite Paper on Critical Load Monitoring

Dupline Safe

Conveyors used in mining are many kilometres long and have pull-cord safety switches located throughout the length. The challenge is to know which switch has been pulled without having to travel down the entire conveyor and check the switches. Dupline Safe has compact, addressable transmitters that are installed inside the switch housing. These can be read via a PLC interface to quickly locate which switch(es) have been pulled.

Our DEA/DEB71 earth leakage monitors provide an early warning to identify bad or worn insulation on power lines and motors and to provide an alarm output to allow maintenance personel to take measures to correct the problem and prevent major equipment damage.

DC Voltage Monitoring

With the increasing global demand for electric vehicles, the demand for EV charging stations is growing as well. In addition to meters for monitoring energy usage in EV charging stations (EV Charging Meters), we also offer DC voltage and current monitoring relays to monitor the voltage and current and provide an alarm in the case either is too high or too low.

We have prepared a useful guide for selecting a monitoring device to protect your machinery. This covers the basics of what needs monitoring as well as well as the consequences of not properly protecting your electrical equipment.
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