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  •   Overload protection relay | motor protection | 5-30A | 180-460VAC
      Overload protection relay | motor protection | 5-30A | 180-460VAC 1
      Overload protection relay | motor protection | 5-30A | 180-460VAC 2
      Overload protection relay | motor protection | 5-30A | 180-460VAC 3
      Overload protection relay | motor protection | 5-30A | 180-460VAC 4

    Overload protection relay | motor protection | 5-30A | 180-460VAC

    Code: ES-SOPR-SS3-30
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    Electronic motor protection relay 5–30A – designed to protect three-phase electric motors against overload, phase loss and locked rotor conditions. The relay operates on a 180–460V AC, 50/60Hz supply and features adjustable D-Time delay from 0.2 to 60 s and O-Time delay from 0.2 to 12 s, LED status indication and a RESET function. It can be mounted on a 35 mm DIN rail or panel plate and is typically used in a contactor control circuit. 

  • Product description

    Electronic motor protection relay | 5-30A | 180-460V AC | overload, phase loss and locked-rotor protection

    Electronic motor protection relay is designed to monitor the operating current of an electric motor and disconnect the control circuit when overload, phase loss or a locked-rotor condition is detected. The relay helps protect the motor from prolonged operation under abnormal conditions and reduces the risk of winding overheating and mechanical damage.

    Current setting range – 5–30A, supply voltage range – 180–460V AC, 50/60Hz. Separate overload and locked-rotor operating times allow the relay response to be adjusted according to the starting and operating characteristics of the specific motor.

    Electronic motor protection

    The relay monitors the actual motor current and, if the configured threshold is exceeded or phase loss or a locked rotor is detected, changes the state of its output contact. In a typical motor control circuit, this contact is normally used to disconnect the contactor control circuit.

    5–30A
    Current range
    180–460V AC
    Supply voltage
    0.2–60s
    Locked-rotor delay
    <2W
    Power consumption

    Operating principle

    The relay continuously monitors the current in the motor circuit. During normal operation, its output contact allows the contactor to keep the motor running. If a configured fault condition is detected, the relay trips and can disconnect the contactor coil through the control contact, thereby stopping the motor.

    Condition Relay response
    Motor operates normally The green PWR indicator shows normal operating status.
    Prolonged overload If the configured current threshold is exceeded and the O-Time delay expires, protection is activated.
    Phase loss If an abnormal phase condition is detected, the relay trips and can disconnect the motor control circuit.
    Locked rotor If high current is present and the motor fails to accelerate, protection trips according to the D-Time setting.
    Protection tripped The red TRIP indicator lights up.

    Overload protection

    Overload protection is intended for situations where the motor draws more current than the configured normal operating value for an extended period. Such a condition may occur due to excessive mechanical load, transmission failure, a jammed mechanism or other causes.

    O-Time – overload operating time

    The overload protection operating time can be adjusted from 0.2 to 12 seconds. The delay can be configured so that a short-duration starting current does not cause unnecessary relay tripping while a real overload is disconnected sufficiently quickly.

    Locked-rotor protection

    If the motor rotor becomes mechanically blocked or the motor cannot accelerate because of excessive load, the motor may begin to draw a very high current. This condition is particularly dangerous for the motor windings.

    D-Time – locked-rotor delay time

    D-Time is adjustable from 0.2 to 60 seconds. This setting allows the protection response to be matched to the normal starting time of the motor.

    Phase loss protection

    For a three-phase motor, the loss of one phase can cause increased current in the remaining phases, reduced torque and rapid motor overheating. The electronic relay monitors the phase condition and can stop the motor when an abnormal operating condition is detected.

    Imbalance monitoring

    The relay provides a ±10% imbalance setting. This function is used to monitor uneven phase operation and helps detect conditions that may be dangerous for a three-phase motor.

    Current setting 5–30A

    The protection current is adjustable within the 5–30A range and must be set according to the rated current of the motor and the requirements of the specific motor manufacturer.

    5–30A is not the load rating of the relay output contact

    The 5–30A range is intended for motor current monitoring and protection settings. The load rating of the relay auxiliary output contact is only 5A / 250V AC with a resistive load. Therefore, the motor is normally controlled through a separate contactor rather than directly through the relay output contact.

    LED current indication and adjustment

    The integrated current indication helps assess the actual motor operating current and set the protection threshold more accurately. LED indicators allow the relay status and protection trip condition to be checked quickly.

    Indication Meaning
    Green PWR Power ON / normal operating status.
    Red TRIP Protection trip.

    Reset after protection trip

    After a protection trip, the relay can be reset using the RESET function. Before restarting the motor, it is recommended to identify and eliminate the cause of the overload, phase loss or mechanical blockage.

    Do not reset the protection before eliminating the fault

    If the motor rotor is mechanically blocked or there is an actual phase or electrical circuit problem, restarting the motor may cause additional damage. The cause of the protection trip must be identified first.

    Wide supply voltage range

    Relay supply voltage – 180–460V AC, 50/60Hz. The wide voltage range makes it suitable for various industrial electrical systems, provided that the parameters of the specific motor and control circuit comply with the relay specifications.

    Mounting

    The relay can be mounted on a standard 35mm DIN rail or on a control panel mounting plate. This allows it to be integrated into both new and modernised motor control panels.

    Typical control circuit

    Power supply → short-circuit protection → contactor → motor
    Electronic overload relay → contactor control circuit

    The relay is designed to monitor the motor condition and control the contactor control circuit. It is not intended to replace the contactor or the short-circuit protection device.

    Technical specification

    Product type Electronic motor overload and protection relay
    Current setting range 5-30A
    Supply voltage 180-460V AC
    Operating frequency 50/60Hz
    Power consumption <2W
    Overload protection Yes
    Phase loss protection Yes
    Locked-rotor protection Yes
    D-Time – locked-rotor delay 0.2-60s
    O-Time – overload operating time 0.2-12s
    Imbalance setting ±10%
    Output contact rating 5A / 250V AC, resistive load
    Operating temperature -20°C...+55°C
    LED PWR Green – normal operating / power status
    LED TRIP Red – protection trip
    Reset RESET function
    Mounting 35mm DIN rail or control panel mounting plate

    Advantages

    • Adjustable 5–30A current protection allows the relay to be adapted to different motors.
    • Overload protection helps protect the motor against prolonged excessive current.
    • Phase loss monitoring is important for protecting three-phase motors.
    • Locked-rotor protection helps provide a fast response to mechanical motor blockage.
    • Separate D-Time and O-Time settings allow more accurate protection adjustment according to motor characteristics.
    • Wide 180–460V AC supply voltage range.
    • 50/60Hz compatibility with various electrical systems.
    • Low power consumption – less than 2W.
    • LED PWR and TRIP indication allows the relay status to be identified quickly.
    • Compact mounting on a DIN rail or control panel plate.

    Disadvantages / limitations

    • Accurate configuration is required: protection current and delays must be matched to the rated data of the specific motor.
    • Does not replace short-circuit protection: a correctly selected circuit breaker or fuses are required in the circuit.
    • The 5A / 250V contact is not intended to switch a 30A motor directly: the motor power circuit is normally controlled by a contactor.
    • Not suitable outside the relay range: the motor rated current must be compatible with the 5–30A adjustment range.

    Suitable for

    • Protection of three-phase electric motors
    • Water pump motors
    • Fan and HVAC motors
    • Conveyor drives
    • Compressors
    • Machine tool and production equipment motors
    • Industrial automation cabinets
    • Modernisation of existing motor protection systems

    Not suitable for

    • Motors whose rated current is outside the 5–30A protection range
    • As a replacement for a short-circuit circuit breaker
    • As a replacement for a power contactor
    • Direct switching of a 30A motor power circuit through the 5A auxiliary contact

    Practical application example

    The rated current of a three-phase pump motor is 18A. The relay current threshold is set according to the motor nameplate data, while the O-Time delay is selected so that the normal motor starting current surge does not cause unnecessary tripping. If the pump becomes blocked and the motor rotor stops mechanically, the current rises sharply. After the configured D-Time expires, the electronic relay trips and disconnects the contactor through the control contact, thereby stopping the motor.

    Frequently asked questions (FAQ)

    What motor current range is this relay designed for?

    The protection current is adjustable within the 5–30A range.

    What is the supply voltage?

    180–460V AC, 50/60Hz.

    Does the relay protect against motor overload?

    Yes. Overload protection is one of the main functions of this device.

    Does it protect against phase loss?

    Yes. Phase loss monitoring is intended to protect a three-phase motor against operation with an incomplete phase supply.

    Does it protect the motor if it becomes mechanically blocked?

    Yes. An adjustable D-Time parameter is used for locked-rotor protection.

    Can a 30A motor be supplied directly through the relay contact?

    No. The relay output contact rating is 5A / 250V AC with a resistive load. The motor power circuit is normally controlled through a contactor.

    Does the relay replace a circuit breaker?

    No. A correctly selected circuit breaker or fuses are required for short-circuit and cable protection.

    How can a protection trip be identified?

    When protection trips, the red TRIP indicator lights up.

    How is the relay reset?

    The RESET function is used. Before resetting, it is recommended to eliminate the cause of the protection trip.

    Important electrical safety and configuration information

    The relay must be installed and configured by a qualified electrical specialist. The protection current must be selected according to the nameplate data of the specific motor, while the D-Time and O-Time delays must be configured according to the motor starting and load characteristics. The relay does not replace a circuit breaker, fuses or a contactor. All power sources must be disconnected before installation or servicing work.

    Electronic motor protection relay 5–30A – a microelectronic overload relay for protecting electric motors against overload, phase loss and locked-rotor conditions. Supply voltage 180–460V AC, 50/60Hz, adjustable D-Time 0.2–60s, O-Time 0.2–12s, output contact rating 5A / 250V AC. Suitable for mounting on a 35mm DIN rail or control panel mounting plate.

    Illustrative image may have been created using AI. The appearance of the product may differ slightly from the image shown. Please refer to the technical specification.

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