3RF2050-1AA04

What type of electrical device is this?

This is a SIRIUS 3RF20 single-phase solid-state relay designed to switch AC loads electronically. It uses zero-crossing operation to reduce switching disturbances and has no mechanically moving contacts.

What load voltage range can the relay switch?

The main circuit is rated for AC operating voltages from 48 to 460 V at 50 or 60 Hz. Its specified operating range extends from 40 to 506 V AC.

What is the maximum rated load current?

The relay is rated for a maximum operational current of 50 A, including AC-51 resistive-load applications. Thermal conditions and ambient temperature must be considered when operating near this rating.

What control voltage is required?

The control input operates from 15 to 24 V DC, with 30 V DC stated as the maximum permissible value. A signal of at least 15 V DC is required for reliable on-state recognition.

Does the relay use zero-crossing switching?

Yes. The 3RF2050-1AA04 switches near the AC voltage zero point, helping to limit electrical disturbance when controlling suitable resistive loads.

What applications is this relay commonly used for?

It is typically used for frequent switching of single-phase resistive loads, including industrial heaters, heating elements, ovens, moulding equipment and temperature-controlled machinery.

Does the relay require a heat sink?

An appropriately selected heat sink or equivalent thermal arrangement is generally required. The relay can dissipate approximately 66 W at its rated current, so heat sink selection should account for load current, ambient temperature and installation conditions.

What are the relay's dimensions?

The unit measures approximately 45 mm wide, 58 mm high and 48 mm deep. Its 45 mm width should be considered when planning control-panel space and heat dissipation.

How is the relay mounted?

The relay uses screw fixing with M4 mounting hardware and can be installed side by side. The maximum specified tightening torque for the fixing screw is 1.5 N·m.

What terminal type does the relay use?

Both the main circuit and control circuit use screw-type terminals. The main terminals have M4 screws, while the control terminals use M3 screws.

What cable sizes can be connected?

The main terminals accept solid or stranded conductors from 1.5 to 6 mm², or finely stranded conductors with suitable end preparation from 1 to 10 mm². The control terminals accept conductors from 0.5 to 2.5 mm².

What terminal tightening torques should be used?

The specified tightening torque is 2 to 2.5 N·m for the main terminals and 0.5 to 0.6 N·m for the control terminals.

What ambient temperatures can the relay operate in?

The specified operating temperature range is -25 to +60 °C. Current derating begins above 40 °C, so the permissible load current may need to be reduced at higher ambient temperatures.

What is the minimum load current?

The specified minimum operational current is 500 mA. Loads below this level may not switch as intended.

What ingress protection rating does the relay have?

The front of the relay is rated IP20 and is finger-safe against vertical contact from the front when correctly installed. It is intended for installation within a suitable enclosure.

How quickly does the relay switch?

The stated switch-on and switch-off delay is 1 ms, plus up to one additional half-cycle of the AC waveform because of its zero-crossing switching behaviour.

What short-duration current can the relay withstand?

The relay has a rated surge-current withstand of 600 A and a maximum I²t value of 1,800 A²s. Correct semiconductor fuse selection remains important for short-circuit protection.

Can this relay switch DC loads?

No. The control input is DC, but the main load circuit is intended for single-phase AC switching. It should not be selected as a DC load-switching relay.