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Undervoltage Protection Relays
-- Steady & Reliable Manufacturer --
Undervoltage Protection Relays
Reliable brownout and phase-loss protection for motors and industrial equipment
Introduction
Undervoltage protection relays monitor power supply voltage levels and disconnect loads when voltage drops below preset values. This protection mechanism prevents equipment damage caused by brownouts, phase loss, or insufficient power supply conditions. Motors, compressors, and other inductive loads particularly benefit from undervoltage protection, as low voltage conditions can lead to increased current draw, overheating, and premature motor failure. Huajin Technology offers undervoltage protection relays with adjustable threshold settings and status indication features.
Specifications
| Parameter | Specification |
|---|---|
| Contact Current Rating | 5A – 60A |
| Coil Voltage Options | 12V, 24V, 48V, 110V, 220V DC |
| Undervoltage Trip Range | 70% – 90% of nominal voltage |
| Response Time | ≤ 50 ms |
| Contact Form | 1A, 1B, 1C |
| Initial Contact Resistance | ≤ 30 mΩ |
| Dielectric Strength (Coil to Contact) | ≥ 4000 VAC / 1 minute |
| Operating Temperature | -25°C to +70°C |
| Detection Method | Continuous monitoring with hysteresis |
| Safety Approvals | CCC, CE, RoHS |
Applications
- Motor protection in industrial machinery
- Compressor control systems
- Elevator and escalator safety circuits
- HVAC equipment protection
- Agricultural irrigation pump systems
Advantages
- Adjustable trip point for various voltage tolerances
- Built-in hysteresis prevents relay chatter
- LED status indication for operating condition
- Magnetic latching eliminates continuous power draw
- Terminal markings simplify wiring and troubleshooting
Frequently Asked Questions
How does undervoltage protection prevent motor damage?
When voltage drops below the rated value, motors draw higher current to maintain output torque, causing excessive heating in the windings. Sustained operation under these conditions can degrade insulation and shorten motor life. The undervoltage relay disconnects the motor before the temperature rises to damaging levels, preventing insulation breakdown and winding burnout.
Can the relay distinguish between undervoltage and phase loss?
Our standard undervoltage relays detect voltage magnitude on each phase. For phase loss detection, a significant voltage drop on one or more phases triggers the protection mechanism. For applications requiring dedicated phase loss monitoring, we offer relays with phase sequence and phase loss detection functions integrated into the same unit.
What is the hysteresis value in undervoltage protection?
The hysteresis is typically set at 2% to 5% of the nominal voltage. For example, if the trip point is set at 80% of nominal voltage (176V for a 220V system), the relay will automatically reset when the voltage rises above approximately 82% to 85% of nominal. This hysteresis prevents relay oscillation caused by marginal voltage fluctuations near the threshold.
Can the undervoltage trip value be adjusted after installation?
Yes. The trip value adjustment dial is accessible from the front of the relay, allowing on-site configuration without removing the unit from the DIN rail. The adjustment range covers 70% to 90% of the nominal voltage, giving installers flexibility to match the specific voltage tolerance requirements of the protected equipment.
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Established in May 2021
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Annual exports account for about 30%
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The company occupies an area of 8,000 square meters.
Huajin Technology Jiaxing Co., Ltd. was established in May 2021 and is located at 707 Yanyu Road, Yucheng Town, Haiyan County, Jiaxing City, Zhejiang Province. It is a high-tech enterprise specializing in the research and development, production, and sales of relays.The registered capital of the company is 10 million yuan, covering an area of 8000 square meters, with more than 120 employees. The annual production capacity of magnetic latching relays is over 10 million, of which exports account for about 30%. The company has obtained ISO9001-2015 quality management system certification, and its relays have passed CCC certification, State Grid certification, TUV certification, etc. It also holds multiple technical patents. Our main products include motor relays, single-phase, two-phase, and three-phase magnetic latching relays, which have a wide variety of types and can meet various customized solutions for customers.
