Phase Relay Order/Absence Asymmetric Voltage

The Schneider Electric Harmony RM17TE00 three-phase control relay is a multifunction device designed to continuously monitor the status of a three-phase electrical network. It can detect phase sequence fault, phase loss, phase imbalance, and overvoltage or undervoltage conditions, providing a compact solution to protect motors, machinery, and other sensitive equipment against power supply anomalies.

The RM17TE00 operates on three-phase networks from 208 to 480 V AC and is powered directly from the monitored network itself, with no need for a separate auxiliary supply. It features a relay output with 1 changeover contact rated at 5 A and allows adjustment of both voltage and imbalance thresholds as well as a fault delay time from 0.1 to 10 seconds.

Multifunction monitoring of three-phase networks

The Schneider Electric RM17TE00 combines different electrical control functions in a single module. It is designed to continuously monitor the three phases and act when it detects conditions outside the configured limits.

Its main functions include:

• Phase sequence control: detects an incorrect order of L1, L2, and L3.
• Phase loss detection: identifies the absence or significant drop of one of the phases.
• Imbalance control: detects excessive voltage differences between phases.
• Undervoltage detection: monitors drops below the set limit.
• Overvoltage detection: monitors increases above the established limit.
• Window mode monitoring: allows the voltage to be monitored so it remains within an acceptable upper and lower range.

The combination of these functions reduces the need to install several independent relays and makes it easier to protect three-phase installations using wired logic.

208 to 480 V AC control range

The relay is designed for three-phase networks with a rated voltage of 208 to 480 V AC and a supply frequency of 50/60 Hz.

Schneider Electric specifies supply and measurement limits of approximately 183 to 528 V AC, providing margin around the nominal range to correctly identify overvoltage and undervoltage conditions.

Measurement is performed on the three-phase network voltages, and the device draws its own power from the monitored phases, so no independent auxiliary power supply is required.

Phase loss protection

Phase loss can cause overcurrent, loss of torque, excessive heating, and damage to three-phase motors. The RM17TE00 continuously monitors the phases and can detect this type of fault.

Schneider Electric specifies a phase loss sensitivity of 0.7 x Un. When the voltage of a phase drops to the level corresponding to the fault condition, the relay changes the state of its output contact so the control circuit can stop the equipment or generate an alarm signal.

Phase order or sequence control

The RM17TE00 checks that the phases are connected in the correct sequence. This function is especially important in three-phase motors, pumps, fans, compressors, and machinery where reversing two phases can cause rotation in the opposite direction to the intended one.

When an incorrect sequence is detected, the output relay switches to the safe state, helping prevent the connected equipment from starting.

Phase imbalance detection

Significant voltage differences between the three phases can affect the operation of motors and other three-phase loads. To prevent this, the RM17TE00 allows an adjustable imbalance threshold between 5 and 15% of the selected rated voltage.

If the difference between phases exceeds the configured value for the set time, the relay can disconnect its output and allow preventive shutdown of the installation.

Overvoltage and undervoltage control

In addition to phase control, this relay monitors whether the voltage remains within set margins around the nominal value.

The voltage threshold can be adjusted up to approximately 2-20% of the selected rated voltage, within the limits corresponding to the supply range used.

This function makes it possible to detect both drops and abnormal increases in voltage and prevent equipment from operating for long periods under unsuitable electrical conditions.

Voltage window mode

Window mode control allows a minimum and maximum limit to be set simultaneously around the nominal voltage. While the voltage remains within the set window, the relay considers the supply to be correct.

When either limit is exceeded, the device starts the fault detection logic and acts on the output contact according to the configured settings.

The device has 2% hysteresis, which helps prevent repetitive contact switching when the voltage is very close to the trip point.

Adjustable delay from 0.1 to 10 seconds

The RM17TE00 features an adjustable delay between 0.1 and 10 seconds associated with the detection of certain fault conditions.

This delay is useful to avoid unnecessary disconnections caused by very brief voltage variations. The installer can adapt the response time to the application requirements using the relay’s front adjustments.

Schneider Electric specifies a delay setting accuracy of approximately ±10% of full scale.

True RMS measurement

The device performs measurement cycles using true RMS technology, with a maximum measurement cycle of approximately 150 ms.

RMS measurement allows the effective level of the electrical voltage to be monitored and provides a suitable reference for determining whether values are within the configured limits.

If a fault is detected, Schneider Electric specifies a response time of less than 200 ms, not including any additional delay set by the user.

Relay output with 5 A changeover contact

The Schneider Electric RM17TE00 includes 1 C/O changeover contact to transmit the network status to the control circuit.

• Configuration: 1 C/O changeover contact.
• Rated output current: 5 A.
• Maximum switching voltage: 250 V AC.
• Switching capacity: 1,250 VA.
• Minimum switching current: 10 mA at 5 V DC.

This output can be used to control a contactor, activate an automation input, or generate an alarm signal when an anomaly is detected.

Fail-safe operation in the event of supply anomalies

The RM17TE00 monitors its own supply. When the three-phase network is within acceptable parameters, the output relay remains in the state corresponding to correct operation.

If the supply changes to an abnormal condition, the output relay de-energizes. This principle makes it easy to create safety circuits in which a power supply failure or monitored anomaly causes the connected equipment to stop.

Protected front adjustments

The parameters are configured using front dials that make it easy to adjust thresholds and delay.

Schneider Electric includes a sealable transparent cover designed to protect the settings from accidental or unauthorized changes once commissioning has been completed.

This feature is especially useful in industrial panels and technical installations where parameters must remain stable after initial configuration.

Compact DIN rail format

One of the advantages of the RM17TE00 is its slim design. With a width of approximately 17.5 mm, it takes up space similar to that of a conventional single-pole modular device.

Its format helps save space inside electrical panels that require multiple protection, control, and monitoring devices.

It is designed for mounting on a 35 mm symmetrical DIN rail, making it easy to integrate into automation and distribution panels.

Applications of the Schneider Electric RM17TE00

The combination of sequence control, phase loss, imbalance, and voltage monitoring makes this relay suitable for many three-phase electrical installations:

• Three-phase electric motors.
• Water pumps.
• Booster sets.
• Compressors.
• Fans and extractors.
• HVAC and air conditioning equipment.
• Industrial machinery.
• Lifting systems.
• Cranes and handling equipment.
• Pumping and water treatment systems.
• Automation panels.
• Electrical panels for buildings and industrial installations.

Ideal for wired automation circuits

The RM17TE00 makes it possible to implement protection and monitoring functions without necessarily using a PLC. When it detects an anomaly, its output contact can be integrated directly into the control circuit of a contactor or other control device.

This makes it a particularly practical solution for simple electrical panels, modernization of existing installations, and applications where compact wired protection logic is required.

Technical features of the Schneider Electric RM17TE00

• Brand: Schneider Electric.
• Reference: RM17TE00.
• Range: Harmony Control Relays.
• Series: RM17TE.
• Type: multifunction three-phase control relay.
• Application: three-phase network monitoring.
• Rated supply and measurement voltage: 208-480 V AC three-phase.
• Supply limits: approximately 183-528 V AC.
• Frequency: 50/60 Hz ±10%.
• Independent auxiliary supply: not required; self-powered device.
• Phase sequence control: yes.
• Phase loss detection: yes.
• Imbalance control: yes.
• Undervoltage control: yes.
• Overvoltage control: yes.
• Voltage window control: yes.
• Adjustable imbalance threshold: 5-15% of Un.
• Adjustable voltage threshold: up to 2-20% of Un depending on selected voltage.
• Hysteresis: 2%.
• Phase loss sensitivity: 0.7 x Un.
• Fault delay: adjustable from 0.1 to 10 s.
• Maximum measurement cycle: 150 ms, True RMS.
• Fault response time: less than 200 ms, excluding set delay.
• Reset time: approximately 1,500 ms.
• Output contact: 1 C/O.
• Contact rated current: 5 A.
• Maximum switching voltage: 250 V AC.
• Switching capacity: 1,250 VA.
• Width: approximately 17.5 mm.
• Mounting: DIN rail.
• Adjustment type: front dials.
• Adjustment cover: transparent and sealable.

Preventive protection for three-phase motors and machinery

Three-phase motors can suffer damage when they operate with a missing phase, excessive imbalance, or voltage outside the permissible limits. Installing a Schneider Electric RM17TE00 phase control relay makes it possible to detect these anomalies before they persist for long periods.

Its output contact can be integrated into the main contactor control circuit to automatically stop the installation when the network no longer meets the established conditions, helping protect motors and reduce downtime caused by electrical problems.

Compact multifunction relay for three-phase networks

The Schneider Electric Harmony RM17TE00 combines phase sequence, phase loss, imbalance, overvoltage, and undervoltage control in a single module. Its 208 to 480 V AC range, configurable delay, and 5 A changeover output make it suitable for a wide variety of industrial and commercial three-phase installations.

At only approximately 17.5 mm wide and with DIN rail mounting, it offers a compact solution for electrical panels where reliable supply monitoring is needed without taking up the space of several independent relays.

Important: the RM17TE00 is a monitoring and control device and does not replace the circuit breakers, residual current devices, or motor protection required by the installation. Its output contact must be integrated into a properly designed control circuit to act on the corresponding switching or signaling elements.