SIRIUS 3RB22 and 3RB23 evaluation modules

The electronic overload relay 3RB22 and 3RB23 up to 630 A (up to 820 A possible with a series transformer) have a modular structure and consist of a processing unit, a current measuring module and a connecting cable. 3RB22 (with monostable auxiliary contacts) and type 3RB23 (with bistable auxiliary contacts) are supplied from an external power supply.

They have been designed for inverse-time delayed protection of loads with normal and heavy starting (for "Function", see Reference Manual) against excessive temperature rises due to overload, phase unbalance or phase failure. An overload, phase unbalance or phase failure result in an increase of the motor current beyond the set rated motor current.

This current rise is detected by means of a current measuring module (see "current measuring modules for 3RB22, 3RB23, 3RB24") and electronically evaluated by the evaluation module which is connected to it. The evaluation electronics sends a signal to the auxiliary contacts. The auxiliary contacts then switch off the load by means of a contactor.

The break time depends on the ratio between the tripping current and the current setting I_e and is stored in the form of a long-term stable tripping characteristic curve, The "tripped" status is signaled by means of a continuous red "OVERLOAD" LED.

The LED indicates imminent tripping of the relay due to overload, phase unbalance or phase failure by flickering when the current limit has been exceeded. This alarm is also issued as a signal through auxiliary contacts for the overload relays 3RB22 and 3RB23 .

In addition to the described inverse-time delayed protection of loads against excessive temperature rises, the 3RB22/3RB23 electronic overload relays also allow direct temperature monitoring of the motor windings (full motor protection) by connection with broken-wire interlock of a PTC sensor circuit. With this temperature-dependent protection, the loads can be protected against overheating caused, for example, indirectly by reduced coolant flow and which cannot be detected by means of the current alone. In the event of overheating, the devices switch off the contactor, and thus the load, by means of the auxiliary contacts. The "tripped" status is signaled by means of a continuously illuminated "THERMISTOR" LED.

To also protect the loads against high-resistance short circuits due to damage to the insulation, humidity, condensed water, etc., the 3RB22 and 3RB23 electronic overload relays offer the possibility of internal ground fault monitoring in conjunction with a function expansion module (for details, see Reference Manual, not possible in conjunction with contactor assemblies for start-delta (wye-delta) starting). In the event of a ground fault the 3RB22/3RB23 relays trip instantaneously.

The "tripped" status is signaled by means of a continuous red "Ground Fault" LED. Signaling through auxiliary contacts is also possible.

After tripping due to overload, phase unbalance, phase failure, thermistor or ground-fault tripping, the relay is reset manually or automatically after the recovery time has elapsed. For "Function", see Reference Manual.

In conjunction with a function expansion module, the motor current measured by the microprocessor can be output in the form of a DC 4 mA to 20 mA analog signal for operating rotary coil instruments or for feeding into analog inputs of programmable logic controllers.

With an additional AS-Interface analog module the current values can also be transferred over the AS-i bus system.

The 3RB2 electronic overload relays are suitable for operation with frequency converters. For more information, see the Reference Manual.

The devices are manufactured in accordance with environmental guidelines and contain environmentally-friendly and reusable materials. They comply with all important worldwide standards and approvals.

Use in hazardous areas

The 3RB22 electronic overload relays (monostable) with the 3RB29 current measuring module are suitable for the overload protection of explosion-proof motors.

EC type test certificate for Category (2) G/D exists. It has the number PTB 05 ATEX 3022.

Article No. scheme

The Article No. scheme shows an overview of product versions for better understanding of the logic behind the article numbers. For your orders please use the article numbers quoted in the selection and ordering data.