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3RA28 function modules for mounting on 3RT2 contactors and 3RH2 contactor relays

Simply by being plugged in place, the SIRIUS function modules enable different functionalities required for the assembly of starters to be realized in the feeder. The function modules and wiring kits thus help to reduce the wiring work within the feeder practically to zero.

SIRIUS function modules for direct-on-line starting

The electronic timing relays which can be mounted onto the contactor are available in these versions:

• Sizes S00 and S0 for applications in the range from 24 to 240 V AC/DC (wide voltage range)
• Size S2 for applications in either the range from 24 to 90 V AC/DC or 90 to 240 V AC/DC

Both the electrical and mechanical connection are made by simple snapping on and locking.

A protection circuit (varistor) is integrated in each module.

The electronic timing relay with semiconductor output uses two contact legs to actuate the contactor underneath by means of a semiconductor after the set time t has elapsed.

The switching state feedback is performed by a mechanical switching state indicator (plunger). In addition, the auxiliary switches in the contactors are freely accessible and can be used for feedbacks to the control system or for signal lamps.

A sealable cover is available to protect against careless adjustment of the set times.

The snap-on function modules for direct starting are used above all for realizing timing functions independently of the control system.

With the OFF-delay variant of the timing relay it is possible for example for the fan motor for cooling a main drive to be switched off with a delay so that sufficient cooling after operation is guaranteed even if the plant and its control system have already been switched off.

The ON-delay timing relays enable for example the time-delayed starting of several drives so that the summation starting current does not rise too high, which could result in voltage failure.

The use of snap-on function modules for direct-on-line starting results in the following advantages:

• Reduction of control current wiring
• Prevention of wiring errors
• Reduction of testing costs
• Implementation of timing functions independently of the control system
• Less space required in the control cabinet compared to a separate timing relay
• No additive protection circuit required (varistor integrated)

For advantages of using wiring kits for the assembly of reversing starters, see "Reversing Contactor Assemblies" → "SIRIUS 3RA23 Reversing Contactor Assemblies".

SIRIUS function modules for star-delta (wye-delta) starting

Both interlocking and timing functions are required for the assembly of star-delta (wye-delta) starters. With the function modules for star-delta (wye-delta) starting and the matching link modules for the main circuit, these starters can be assembled easily and with absolutely no errors.

The entire sequence in the control circuit is integrated in the snap-on modules. This covers:

• An adjustable star time t from 0.5 to 60 s
• A non-adjustable dead interval of 50 ms
• Electrical contacting to the contactors by means of coil pick-off (contact legs)
• Feedback of the switching state at the contactor using a mechanical switch position indicator (plunger)
• Electrical interlocking between the contactors

These modules do not require their own terminals and can therefore be used for contactors with both screw and spring-type terminals in all the sizes S00 to S2. To start the star-delta (wye-delta) starter, only the first of the three contactors (line contactor) is actuated. All other functions then take place inside the individual modules.

This also offers advantages if the timing function was previously implemented in a controller, as it again results in a significant reduction in the number of PLC outputs, the programming work and the wiring outlay.

The kits for the main circuit include the mechanical interlock, the star jumper, the wiring modules at the top and at the bottom, and the required connectors or connecting clips.

A protection circuit (varistor) is integrated in the basic module.

The function modules for star-delta (wye-delta) starting are mostly used where current-limiting measures for starting a drive are required, e.g. for large fans and ventilators, and a high level of availability is essential at the same time. This technology has been used with success for several decades and has the additional advantage of requiring relatively little know-how. Through the use of function modules, the assembly work with simple standard components is even easier and error-free.

The use of function modules for star-delta (wye-delta) starting results in the following advantages:

• Operation solely through the line contactor A1/A2 – no further wiring needed
• Reduction of the control current wiring inside the contactor assembly and to the higher-level control system where applicable
• Prevention of wiring errors
• Reduction of testing costs
• Integrated electrical interlocking saves costs and prevents errors
• Less space needed in the control cabinet compared to using a separate timing relay
• Adjustable starting in star mode from 0.5 to 60 s
• Independent of the contactor''s control supply voltage (24 to 240 V AC/DC)
• Varistor integrated – no additive protection circuit required
• No control current wiring thanks to plug-in technology and connecting cables
• Mechanically coded assembly enables easy configuration and reliable wiring
• Fewer versions – one module kit for screw and spring-type connection and for all the contactor sizes S00 to S2. Mechanical interlocking (with wiring kit for the main circuit)