SFK-T3 Series Switches-Xinxiang Shengyuan Electric Co., Ltd.

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Overview

The SFK-T3 series zero-transition synchronous switch is a newly developed capacitor switching device specifically designed to address the shortcomings of conventional AC contactors and hybrid switches in low-voltage reactive power compensation systems. Combining mechanical switching technology with modern microelectronics, this innovative product boasts numerous advantages, including low power consumption, seamless switching without inrush current, insensitivity to harmonics, and highly effective compensation.

Technical Specifications

Operating voltage: 400V ±10%
Rated frequency: 50 Hz ± 5%
Control capacity: Three-phase common compensation △ type, maximum capacity: ≤30 kVAR
Single-phase split-compensation Y-type maximum capacity: ≤3 × 10 kVAR
Insulation rating: Under normal atmospheric conditions ≥10 MΩ
Control Method: 12V Level Signal

Key Features

1. Zero-Transition Switching
Precisely control the timing of switching operations to ensure activation occurs when the rate of change in grid voltage and current is zero, thereby achieving a zero-transition process with no inrush current and no harmonics.
2. Provides overcurrent and current imbalance (common compensation) protection for the capacitor in this branch circuit.
3. Low power consumption
Thanks to the use of a magnetic latching relay, the control device consumes power only during the switching operation—no power is used at other times. Additionally, because the magnetic latching relay has low contact resistance, it generates minimal heat. This eliminates the need for external heat sinks or fans, further reducing costs and power consumption, thereby achieving the goal of energy conservation and efficiency improvement.

Model Naming

SFK-T3 Series Synchronous SwitchesModule
SFK - T3 / 30 / S / 450 / A
丨丨丨丨丨丨
① ② ③ ④ ⑤ ⑥
①: Product Code: SFK
②: Product Category: T3 Series
③: Rated Capacity: 5–50 kvar
④: Compensation Method: (F: Partial Compensation, S: Shared Compensation)
⑤: Rated Voltage: 250V, 450V
⑥ : A: 12V

Installation Notes and Wiring Diagrams

Meaning of the fault:
The switch features an internal detection module that monitors the operational status of its internal components. If an abnormality is detected in the internal components, the switch automatically trips and disconnects power. Relevant personnel can determine the fault location—and subsequently apply an appropriate troubleshooting method—by counting the number of times the power indicator light flashes intermittently.
The power indicator light flashes once – Internal failure
The power indicator light flashes twice—Phase A input fault.
The power indicator light is flashing 3 times—Phase C input fault.
The power indicator light flashes 4 times — Phase A fault isolated.
The power indicator light flashes 5 times—Phase C fault isolated.
The power indicator light flashes 6 times—capacitor overcurrent protection is activated.
The power indicator light flashes 7 times — capacitor current imbalance protection
The power indicator light flashes 8 times—contact protection.
The power indicator light flashes 9 times—no capacitor current protection after startup.
When the above situation occurs, you can disconnect power from the switch for 10 minutes and then reconnect it, observing whether the issue reappears. This will help determine whether the problem is caused by a faulty switch or by temporary abnormalities in the power grid or capacitors.
The fixing screws for the main incoming and outgoing lines of the switchgear should be inspected and tightened monthly to ensure proper contact.

Installation Diagram