The Siemens 3RP1574-1NM208K is a star-delta electronic timer from the Siemens 3RP series, designed for industrial motor-control applications where a controlled transition from star starting to delta running is required. It provides 1 NO instantaneous contact and 1 NO delayed contact, allowing the timer to coordinate the operation of the star and delta contactors.
This timer is suitable for electrical control panels, OEM machinery, industrial automation systems and conventional star-delta motor starters.
The 3RP1574-1NM208K is designed for timing functions in star-delta motor starting circuits.
A typical operating sequence is:
Start Command → Star Contactor ON → Time Delay → Star Contactor OFF → Delta Contactor ON
The timer helps establish the required timing relationship between the motor-starting stages.
Star-delta starting is commonly used for suitable motors where a reduced starting-current effect is desired compared with direct-on-line starting.
The timer provides 1 normally open instantaneous contact.
This contact operates immediately according to the control condition and can be incorporated into the motor starter's control logic.
Typical uses include:
The exact function depends on how the timer is connected within the complete control circuit.
The 3RP1574-1NM208K also provides 1 normally open delayed contact.
The delayed contact changes state after the configured timing interval and can be used to coordinate the star-to-delta transition.
Typical uses include:
The required timing should be selected according to the motor characteristics, load and complete starter design.
In a conventional star-delta starter, the motor initially operates in the star connection and then changes over to the delta connection after the required delay.
A simplified sequence is:
Motor Start → Star Mode → Timed Transition → Delta Mode
This arrangement can help reduce starting-current effects and mechanical stress for suitable motor and load combinations.
The complete starter should use appropriately rated main, star and delta contactors together with suitable overload and short-circuit protection.
The 3RP1574-1NM208K belongs to the Siemens 3RP electronic timer family, designed for timing and sequence-control applications in industrial electrical systems.
The timer can be integrated with components such as:
This makes it suitable for both conventional control panels and broader industrial automation applications.
The 3RP1574-1NM208K can be used where star-delta motor starting is appropriate.
Typical applications include:
The suitability of star-delta starting should always be evaluated against the motor type, load characteristics and starting requirements.
The 3RP1574-1NM208K is suitable for OEM machine manufacturers, electrical panel builders, automation integrators and industrial maintenance professionals.
Its combination of 1NO instantaneous and 1NO delayed contacts provides a practical timing solution for conventional star-delta motor-control circuits.
The Siemens 3RP1574-1NM208K provides a dedicated electronic timing solution for star-delta motor starters, combining 1NO instantaneous and 1NO delayed contacts for control-sequence coordination.
It can be integrated with correctly rated star, delta and main contactors, overload protection and appropriate interlocking to create a complete industrial motor-control system.
For OEMs, panel builders and automation integrators, it is a practical solution for conventional star-delta starting applications.
SB Smart supplies Siemens industrial electrical and automation products across Faridabad, Gurgaon/Gurugram, Delhi NCR, Haryana, Noida, Punjab, Mumbai and all major cities across India.
Major delivery locations include:
It is a Siemens 3RP star-delta electronic timer with 1NO instantaneous and 1NO delayed contacts.
It is designed for star-delta motor-starting circuits, where timed sequencing is required for the transition from star to delta.
It has 1 NO instantaneous contact.
It has 1 NO delayed contact.
The delayed contact can be used to provide the timed control signal required for the star-to-delta transition.
It coordinates the sequence and timing of the star and delta contactors during motor starting.
Yes. The contacts can be incorporated into a suitable star-delta contactor-control circuit.
Yes. Proper electrical and/or mechanical interlocking is essential to prevent simultaneous energization of the star and delta contactors.
It can be used in motor-control panels, pumps, fans, compressors, conveyors, production machinery and OEM equipment where star-delta starting is appropriate.
You can explore the Siemens product range at SB Smart for Siemens electronic timers, contactors, overload relays and other industrial automation products.
| Specification | Details |
|---|---|
| Product Name | Electronic Star Delta Timer Relay |
| Manufacturer | Siemens |
| Series | SIRIUS 3RP |
| Model Number | 3RP1574-1NM208K |
| SKU | 3RP1574-1NM208K |
| Product Type | Star Delta Timer |
| Function | Star-Delta Switching |
| Contact Configuration | 1 NO Instantaneous + 1 NO Delayed |
| Time Range | 1 – 20 Seconds |
| Control Supply Voltage | 200–240V AC / 380–440V AC |
| Frequency | 50/60 Hz |
| Technology | Solid-State Electronic Timer |
| Mounting Type | 35 mm DIN Rail Mounting |
| Housing Width | 22.5 mm |
| Terminal Type | Screw Terminals |
| Number of Outputs | 2 NO Contacts |
| Protection Rating | IP20 |
| Application | Star Delta Motor Starter Control |
| Suitable Motors | Three-Phase Induction Motors |
| Industrial Applications | Pumps, Compressors, HVAC, Conveyors, Mixers |
| Product Family | Siemens SIRIUS Timing Relays |
| Brand | Siemens |
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