| Nominal supply voltage and phase | Rated input and output voltage; single-phase or three-phase configuration | Common nominal supplies in China are 220 V single-phase and 380 V three-phase at 50 Hz. | The stabilizer must match the electrical system and the connected equipment. | Confirm the site supply and equipment nameplate. For three-phase loads, check whether the load requires a three-phase unit and how phase imbalance is handled. |
| Input-voltage range | Minimum and maximum input voltage at which the unit can regulate its rated output | Ranges such as 140–260 V or 160–250 V are found on some single-phase models; available ranges vary by model and capacity. | A wider range can help where supply voltage regularly fluctuates, but the rated output capacity may be reduced at low input voltage. | Measure or log the lowest and highest site voltage before choosing. Check the manufacturer’s capacity-versus-input-voltage curve, not just the headline range. |
| Rated capacity | Continuous capacity in kVA or kW, plus any derating conditions | Capacity should be selected from the connected load’s actual operating demand; kW and kVA are not interchangeable unless power factor is considered. | An undersized unit may overheat, trip, or fail to start a load. A unit selected only by the sum of appliance wattages may not account for power factor or starting current. | Calculate the simultaneous load, account for power factor, and leave a suitable margin. For motors and compressors, check starting current and the stabilizer’s overload capability. |
| Output-voltage accuracy | Regulation accuracy under specified input, load, and temperature conditions | Published accuracy varies by design and model; values around ±2% to ±5% are specified by some products. | Sensitive equipment may require tighter voltage control than general lighting or heating loads. | Compare accuracy specifications under the same test conditions. Verify that the required accuracy is maintained across the expected input range and load level. |
| Stabilizer technology and response | Regulation method, correction speed, and performance during abrupt voltage changes | Relay-switched, servo-controlled, and static electronic designs have different switching behavior, correction characteristics, and maintenance needs. | Technology affects response, output stability, noise, wear components, and suitability for the application. | Choose by load sensitivity and operating environment. Ask for documented response and regulation data; avoid comparing response figures that use different test methods. |
| Protection functions | Overload, overvoltage, undervoltage, short-circuit, overheating, and bypass protection | Protection features differ among models and may have adjustable thresholds or time delays. | Protection can disconnect the load when the supply or stabilizer operates outside safe limits; it does not replace proper circuit protection. | Check trip thresholds, reset behavior, alarms, and whether a bypass mode is available. Coordinate the unit with correctly rated upstream breakers and downstream protection. |
| Efficiency and heat dissipation | Efficiency at representative loads, ventilation requirements, and permissible ambient temperature | Efficiency is model- and load-dependent; losses are converted to heat inside the unit. | Heat affects energy use, component life, and reliable operation, especially in continuously loaded installations. | Review efficiency data at the expected operating load. Provide the specified ventilation clearances and avoid dusty, damp, or excessively hot locations unless the enclosure is rated for them. |
| Installation and operating environment | Indoor or outdoor rating, enclosure protection, wiring, grounding, and service access | Enclosure ratings and installation requirements are product-specific; outdoor suitability should not be assumed. | Correct installation reduces electrical hazards and helps prevent moisture, dust, and heat from damaging the unit. | Follow the unit’s installation manual and applicable local electrical requirements. Confirm cable and terminal ratings, grounding, phase arrangement, and access for inspection. |
| Standards, testing, and documentation | Applicable conformity documents, test reports, technical datasheet, and warranty terms | Requirements depend on product type, intended use, and the relevant regulations or procurement specification. | Clear documentation helps verify ratings and supports safe installation, maintenance, and procurement decisions. | Request the exact model’s datasheet and test documentation. Verify that stated ratings apply to the intended configuration and are not based solely on marketing descriptions. |