STVP-935S 3-Phase Voltage Protector Auto Transfer Switch 40A–100A
STVP-935S 3-Phase Voltage Protector Auto Transfer Switch 40A–100A
STVP-935S 3-Phase Over/Under Voltage Protector with Automatic Transfer Switch
Keep your three-phase electrical systems running smoothly with the STVP-935S Automatic Transfer Switch and Voltage Protector. Designed for industrial and commercial DIN-rail installations, this microcontroller-based device continuously monitors all three phases (L1, L2, L3) and automatically switches to a healthy phase whenever overvoltage, undervoltage, or phase-loss is detected — all without interrupting your connected load. Available in 40A, 63A, 80A, and 100A rated current options to suit a wide range of applications.
Key Features
- Automatic Transfer Switch (ATS): Seamlessly switches to a healthy phase with priority order L1 > L2 > L3 — keeping your equipment running without manual intervention.
- Microcontroller-Based Intelligence: Precise, fast, and reliable phase monitoring via onboard microcontroller for consistent performance.
- Overvoltage Protection: Configurable overvoltage detection range of 230–300V to guard sensitive equipment against voltage surges.
- Undervoltage Protection: Configurable undervoltage detection range of 140–210V to prevent damage from low-voltage conditions.
- Overcurrent Protection: Built-in overcurrent safeguard protects downstream equipment from excessive current draw.
- Phase-Loss Detection: Automatically detects a missing phase and transfers to a functioning phase immediately.
- LED Working Voltage Indicator: At-a-glance visual status display for quick diagnostics and system monitoring.
- DIN Rail / Guide Rail Installation: Standard DIN rail mounting for easy integration into electrical panels and distribution boards.
- Wide Current Range: Available in 40A, 63A, 80A, and 100A versions to match your system's load requirements.
- Wide Storage Temperature Range: Rated for storage from -25°C to +55°C, suitable for a variety of environments.
Technical Specifications
| Parameter | Value |
|---|---|
| Model | STVP-935S |
| Rated Working Current | 40A / 63A / 80A / 100A |
| Power Terminals | N, L1, L2, L3 |
| Overvoltage Detection Range | 230V – 300V |
| Undervoltage Detection Range | 140V – 210V |
| Phase Transfer Priority | L1 > L2 > L3 |
| Storage Temperature | -25°C to +55°C |
| Installation Type | DIN Rail (Guide Rail) |
| Country of Origin | Made in China |
How It Works
When any one of the three phases (L1, L2, or L3) experiences an overvoltage, undervoltage, or phase-loss event, the STVP-935S relay automatically disconnects from the affected phase and scans for the next healthy phase in priority order (L1 first, then L2, then L3). It then seamlessly switches your connected load to that healthy phase — all in real time, with no manual reset required.
What's in the Box
- 1× STVP-935S Over/Under Voltage Protector & Automatic Transfer Switch
Please Note: Slight color variations may occur due to monitor settings. Allow 1mm–1cm dimensional tolerance due to manual measurement.
For guidance on electrical safety standards and best practices for electrical installations, refer to the OSHA Electrical Safety Guidelines.
Frequently Asked Questions
Q: What is the switching priority of the STVP-935S automatic transfer switch?
A: The STVP-935S uses a fixed priority order of L1 > L2 > L3. When the currently active phase experiences a fault (overvoltage, undervoltage, or phase loss), the unit automatically transfers to the next available healthy phase in this priority sequence — ensuring your equipment stays operational with minimal interruption.
Q: Which current rating should I choose — 40A, 63A, 80A, or 100A?
A: Select the current rating that matches or slightly exceeds the maximum load current of your connected equipment. As a rule of thumb, the rated current of the protector should be at least equal to your circuit's maximum expected load current. Consult a qualified electrician if you are unsure of your system's load requirements.
Q: Can the STVP-935S be installed in a standard electrical panel?
A: Yes. The STVP-935S is designed for standard DIN rail (guide rail) mounting, making it straightforward to integrate into most electrical distribution boards and industrial control panels. Always have installation performed by a licensed electrician in accordance with local electrical codes.
Q: Does the STVP-935S protect against both high and low voltage simultaneously?
A: Yes. The device monitors all three phases simultaneously for both overvoltage (230–300V range, adjustable) and undervoltage (140–210V range, adjustable) conditions, as well as phase loss — providing comprehensive three-phase voltage protection in a single compact unit.