| Brand | HK Electrical |
| Model NO. | GRT8-ST Delay ON Star/Delta Timer Relay |
| Rated frequency | 50/60Hz |
| Series | GRT8 |
The GRT8-ST Delay ON Star/Delta Timer Relay is a specialized timing control device for star-delta motor starting systems. It precisely manages the delay time between star and delta connection modes, reducing inrush current during motor startup to protect equipment and ensure smooth, stable operation. Widely used in industrial motors like pumps, fans and compressors, it enhances motor service life and overall system reliability.
Designated for delay ON of motors star/delta.
Accurate Delay Control: Provides precise adjustment of star-delta conversion delay, meeting different motor startup timing requirements.
Motor Protection: Reduces inrush current during startup, preventing damage to motors and associated electrical components.
Industrial-Grade Reliability: Built with durable components, suitable for harsh industrial environments with stable performance.
Easy Integration: Standard wiring and interfaces allow seamless connection to star-delta motor control circuits.
Function Features
Time t1 (star) : time scale 0.1 s – 10min divided into 4 time ranges rough time setting by rotary switch.
Time t2 (delay) : time scale 0.1 s – 1 s time setting by potentiometer
Relay status is indicated by LED.
1-MODULE, DIN rail mounting.
Parameter
| Technical parameters | GRT8-ST |
| Function | Delay ON star /Delta |
| Supply terminals | A1-A2 |
| Voltage range | AC/DC 12-240V(50-60Hz) |
| Burden | AC 0.3-2VA/DC 0.1-1.2W |
| Voltage range | AC 230V(50-60Hz) |
| Power input | AC max.6VA/1.3W |
| Supply voltage tolerance | -15%;+10% |
| Supply indication | green LED |
| Time ranges | Range of time delay t1:0.1s-10min,Switch time t2:0.1s-10s |
| Time setting | potentiometer |
| Time deviation | 10%-mechanical setting |
| Repeat accuracy | 0.2%-set value stability |
| Temperature coefficient | 0.05%/℃,at=20℃(0.05%℉，at=68℉) |
| Output | 2×SPDT |
| Current rating | 16A(AC1) |
| Switching voltage | 250VAC/24VDC |
| Min. breaking capacity DC | 500mW |
| Output indication | red LED |
| Mechanical life | 1×107 |
| Electrical life(AC1) | 1×105 |
| Reset time | max.200ms |
| Operating temperature | -20℃ to+55℃（-4℉to131℉） |
| Storage temperature | -35℃ to+75℃（-22℉to158℉） |
| Mounting/DIN rail | Din rail EN/IEC 60715 |
| Protection degree | IP40 for front panel/IP20 terminals |
| Operating position | any |
| Overvoltage category | III. |
| Pollution degree | 2 |
| Max.cable size(mm 2) | solid wire max.1×2.5or 2×1.5/with sleeve max.1×2.5(AWG 12) |
| Tightening torque | 0.4Nm |
| Dimensions | 90×18×64mm |
| Weight | W240-82g,A230-80g |
| Standards | EN 61812-1,IEC6947-5-1 |
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