The purpose of the 3UG546 DC load monitoring relay is to monitor DC applications in industrial applications. It monitors the direct current (DC load current circuit), voltage, and actual power for overshooting or undershooting of set limit values in one or two channels. This means that current, voltage and power can be monitored separately.

Besides providing detailed error diagnostics, the integrated energy counters, operating hour counters and switching cycle counters can also be read out and reset, making it possible to reliably maintain the system. The relay identifies the direction of current flow so that the quantities of energy stored in or drawn from a battery, for example, can be recorded separately.

The 3UG546 DC load monitoring relay can be fully parameterized via Profinet and transfers the measuring and metering values and diagnostic messages via Profinet to the control system. After the signaling or switching function is performed via an internal relay output, reliable error responses are also possible without Profinet.

It covers a wide operating voltage range from 0 to 800 V. In this current range two versions are available: 22.5 mm wide: 2x8 A / 1x16 A and 45 mm wide: up to 63 A.

The SIRIUS 3UG4 monitoring relays monitor the most diverse electrical parameters in the feeder, and provide reliable protection against damage in the plant. They not only feature freely parameterizable threshold values and manifold adjustment options, but also provide conclusive diagnostics and are even able to correct an incorrect phase sequence autonomously. Numerous versions are also available with IO-Link interface for connection to the controller.

The SIRIUS 3UG4 monitoring relays also monitor mechanical variables.

The level monitoring relays ensure reliable 1 or 2-point controls and alarm messages in the event of overflow or dry running.

The speed monitoring relays check whether the nominal speed of motors, shafts or powered wheels is exceeded or not reached. Moreover, the relays are suitable for all functions requiring the monitoring of a continuous pulse signal. Optionally with IO-Link connection.

As well as monitoring of motors or other loads, the SIRIUS 3RR2 current monitoring relays are especially suitable for optimum current monitoring of the overall plant or of the powered process. Thus, load shedding or overload of the motor, for example, is detected quickly and reported early. The 3RR2 monitoring relay for current monitoring is integrated directly in the load feeder. It simply plugs into the contactor. Also available with IO-Link connection.

Thermistor motor protection relays provide decisive benefits in cases in which current-dependent protection using either a circuit breaker or an overload relay is not the perfect solution: In certain cases, overheating can occur without being detected by the thermal image in the circuit breaker/overload relay, for example in the case of heavy starting, operation with frequency converters or frequent switching, strong braking operations or restricted cooling. The 3RN2 thermistor motor protection relays provide a reliable protection against motor overheating by measuring the temperature at the hot points in the inside of the motor. They monitor the winding temperature of motors directly.

The 3RS2 temperature monitoring relays can be used to measure temperatures in solid, liquid and gaseous media. The temperature is acquired by means of sensors in the medium, evaluated by the device, and monitored for overshoot, undershoot or within a specified operating range (window function).

The family comprises an analog multi-function device which can be set using rotary and slide switches, and digital devices which can be parameterized via an intuitive LCD display.

The function of the digital devices can be extended without wires via a SIL1-certified infrared communications interface with a sensor extension module. This combination features three resistance sensors, this way the temperature in every winding of three-phase motors and transformers can be monitored optimal.

All digital devices have safety certification according to IEC 61508/62061 or ISO 13849 up to SIL 1 / PL c as well as EN 14597 and burners according to EN 50156 and are also available as IO-Link version. 

The new 3RS2 temperature monitoring relays replace the predecessor 3RS1.