The difference and application scenarios between voltage type protectors and current type protectors

Voltage type protectors and current type protectors are both devices used for protecting electrical equipment, but their working principles, detection objects, and application scenarios are different.

1. Working principle of voltage type protector

Voltage type protectors mainly monitor voltage changes in circuits and issue alarms or perform protective actions in case of abnormal voltage (overvoltage or undervoltage) to prevent electrical equipment from being damaged due to voltage abnormalities.

Main functions

·overvoltage protection：When the power supply voltage exceeds the set value, the circuit is cut off or an alarm is triggered to prevent equipment damage due to high voltage.

·Undervoltage protectionWhen the power supply voltage is lower than the set value, the circuit will be cut off or an alarm will be triggered to avoid abnormal operation of the equipment due to low voltage.

·phase loss protection(Applicable to three-phase systems): Check whether the three-phase power supply is normal to prevent motor damage due to phase loss.

·phase sequence protection(Applicable to three-phase systems): Ensure that the motor phase sequence is correct and avoid reverse faults caused by phase sequence errors.

Application scenarios

·industrial control systemUsed to prevent equipment from malfunctioning or being damaged due to abnormal voltage, such asPLC、 Voltage monitoring of equipment such as motors and frequency converters.

·Household appliance protectionOvervoltage and undervoltage protection for household appliances such as refrigerators, air conditioners, and televisions.

·power systemUsed for voltage monitoring in high and low voltage power supply networks to prevent fluctuations in grid voltage from affecting equipment operation.

·UPS power supply and regulated power supply systemEnsure that the power supply voltage is within a reasonable range.

2. Working principle of current type protector

Current type protectors determine the operating status of equipment by detecting the magnitude of current in the circuit, and perform protective actions in case of abnormal current (overcurrent, undercurrent, or phase loss) to prevent damage to motors and electrical equipment due to abnormal current.

·overcurrent protectionWhen the current exceeds the set value (such as motor overload, short circuit, etc.), the circuit will be automatically disconnected or an alarm will be triggered to prevent equipment damage.

·Undercurrent protectionWhen the current is lower than the set value (such as when the equipment is unloaded, disconnected, etc.), the protection action is triggered to avoid damage to the equipment due to no-load operation.

·phase loss protectionMonitor whether the three-phase current is balanced to prevent the motor from burning out due to phase loss operation.

·locked-rotor protection(Applicable to motors): When the motor rotor cannot rotate normally and the current increases abnormally, the protector will quickly cut off the power supply.

·short circuit protectionWhen a sudden increase in current is detected, quickly cut off the power supply to prevent circuit burnout or equipment damage.

Application scenarios

·Motor protectionCommonly used for overload, short circuit, and phase loss protection of motors, such as fans, water pumps, compressors, and other equipment.

·Industrial automation equipmentProtect the safe operation of equipment such as frequency converters and servo motors.

·power systemUsed for short circuit and overload protection in power transmission and distribution systems.

·Welding equipment, heating equipmentTo prevent equipment damage or cable overheating caused by current overload.

·Wind power generation, photovoltaic power generation systemMonitor and protect the current of inverters and grid connected equipment.

How to choose the appropriate protector?

1. Motor equipmentprepareIf it is a load such as a motor, it is recommended to chooseCurrent type protector(such asEOCR electronic motor protector can effectively prevent faults such as overload, phase loss, and locked rotor.

2. power systemIf you are concerned about power supply quality, chooseVoltage type protectorEnsure voltage stability and avoid overvoltage or undervoltage affecting the equipment.

3. comprehensive protectionSome equipment such as precision industrial equipment and motor control systems may requirevoltage+Current protectionA combination plan to ensure stable operation of the equipment.

5. Typical product recommendations

SchneiderEOCR China General Agent - Shanghai Hanshi Electric can provide:Voltage type protector：EOVR/EUVR DOVR/DUVR EVR-PD/FD(discontinue production) PMR(discontinue production) upgrade productEVR1P22 EVR3P44 and voltage current combination products such as ISEMZ ISEMD ISEMM

Shanghai Hanshi Electric can also provideCurrent type protector：Schneider EOC Electronic Motor Protector ABB MS116 motor protection circuit breaker Siemens 3RV series motor protection circuit breaker

·Voltage type protectorSuitable for power supply system and power quality monitoring, protecting equipment from abnormal voltage effects.

·Current type protectorSuitable for protecting loads such as electric motors and industrial equipment to prevent overcurrent, short circuit, and phase loss issues.

·In practical applications, it is necessary to select appropriate protectors based on the specific characteristics of the equipment to ensure the stable operation of the system.

If you have specific application scenarios or product selection requirements, you can provide detailed information,SchneiderEOCR China Agent - Shanghai Hanshi ElectricCan you recommend more specific models and solutions!