Schneider Electric RM22UA33MT monitoring for over- and under-voltage with memory 2W content_copy

The voltage monitoring relay RM22UA33MT from Schneider Electric belongs to the Harmony control relays product line and is designed for continuous monitoring of a measurement circuit for overvoltage or undervoltage. It detects deviations in the voltage range of 15 to 500 V AC/DC and responds according to the setting to overvoltage, undervoltage, or both in window mode. The function is signaled via 2 changeover contacts, rated for a load up to 8 A and enabling a switching capacity of 2000 VA. Power supply is provided via a nominal voltage of 380 to 415 V AC at 50/60 Hz, with supply voltage limits ranging from 323 to 456.5 V AC. The power consumption is 8 VA AC.

Applications include monitoring electrical systems in industrial environments where stable voltage protection is required. The device is designed for use in single-phase systems and is suitable for integration into control and protection systems, particularly in installations with high operational safety requirements. Settings for the threshold value, switching hysteresis (fixed at 3 % of full scale in window mode, adjustable from 5 to 50 % of the threshold setting) and time delay (0.1 to 30 seconds, ±10 % accuracy) are adjusted via controls on the front panel. An illuminated scale pointer enables clear visibility of the settings even from a distance. The settings can be protected against unintended changes using a transparent cover.

Functions and equipment in detail include an integrated diagnostic switch on the front, which allows temporary deactivation of the output relay to test the entire system. When the transparent cover is closed, this switch is automatically reset. Two LEDs indicate operating and fault status. Optionally, a fault memory can be activated, which retains the fault message until manual reset. The reset time is 1500 ms at maximum voltage, and the turn-on delay is 600 ms. Repeatability is ±0.5 % for input and measurement circuit, and ±2 % for time delay. The measurement error is less than 1 % across the entire range under voltage fluctuations and 0.05 %/°C under temperature fluctuations.

Technology explained simply shows that the device operates with a true RMS measurement cycle of up to 100 ms, enabling precise voltage analysis. The insulation between supply and measurement circuit ensures electrical safety. The contact materials are cadmium-free, meeting environmental requirements. The electrical life is 100,000 switching cycles, and the mechanical life is 10,000,000 cycles. Insulation resistance exceeds 100 MΩ at 500 V DC.

Compatibility and accessories include mounting on a 35 mm DIN rail in accordance with IEC 60715. Suitable accessories include the PLC control TM221CE16T, equipped with positive logic and Ethernet connection. The terminals are screw terminals and support various conductor cross-sections: 0.5 to 2.5 mm² (AWG 20–14) for rigid conductors without cable ends, 0.2 to 1.5 mm² (AWG 24–16) for flexible conductors with cable ends, and 0.5 to 3.3 mm² (AWG 20–12) for rigid conductors without cable ends at an additional connection. The tightening torque is 0.6 to 1 Nm.

Mounting and installation is done on the DIN rail. The housing is made of polycarbonate and is designed for industrial environments. The protection rating is IP20 at the terminals, IP20 at the housing, and IP20 at the front panel. The operating temperature ranges from -20 to 50 °C at 60 Hz or -20 to 60 °C at 50 Hz. The storage temperature is -40 to 70 °C. Relative humidity is 93 to 97 % at 25 to 55 °C. Vibration resistance complies with IEC 60068-2-6, and shock resistance with IEC 60068-2-27. The overvoltage category is III, and the pollution degree is 3 according to IEC 60664-1. The dielectric test voltage is 2.5 kV, 1 min AC 50 Hz.

Operational advantages include high measurement precision, simple operation via front controls, clear status indication via LEDs, and robust construction for industrial applications. The combination of adjustable parameters and integrated diagnostic functions enables flexible and reliable integration into existing control systems. The width is 22.5 mm, the height is 90 mm, and the depth is 73 mm. Reliability is underscored by an MTTFd of 308.2 years and a B10d value of 290,000 cycles. Batteries are not included in the delivery scope.

Additional features
[UH,nom] Rated operating voltage	380 - 415 V AC 50/60 Hz, not battery-operated
Supply voltage limits	323…456,5 V AC
Power consumption in VA	8 VA AC
Measuring range	15 - 500 V AC/DC
Maximum measurement cycle	100 ms measurement cycle as true RMS value
Hysteresis	3 % fixed from full scale for window mode; 5…50 % adjustable from threshold setting
Repeatability	± 0.5 % for input and measurement circuit; ± 2 % for time delay
Measurement error	< 1 % over full range with voltage variation; 0.05 %/°C with temperature variation
Time delay	Adjustable 0.1 - 30 s, ± 10 % of full scale value Tt – delay time during fault
Time delay adjustment accuracy	10 %
Reset time	1500 ms at maximum voltage
On-delay	600 ms
Output contacts	2 changeover contacts
Rated output current	8 A
Max. switching voltage	250 V AC
Switching power in VA	2000 VA
Min. switching current	10 mA at 5 V DC
Max. switching current	8 A AC
Electrical lifetime	100000 cycles
Mechanical life	10000000 cycles
Contact material	Cadmium-free
Resistance across terminals	150 kOhm at E2-M terminals; 300 kOhm at E1-M terminals; 500 kOhm at E3-M terminals
Insulation	Between supply and measurement
Contractual warranty
Warranty (in months)	18
Main features
Product series	Harmony control relay
Device type	Voltage monitor
Product or component type	Voltage monitor
Relay designation	RM22UA
Relay-monitored parameters	Detection of overvoltage or undervoltage; Undervoltage and overvoltage in window mode
Control type	With test button
Contact type and composition	2 changeover contacts
Number of power phases	1 Phase
Type of power supply circuit	DC
Mounting
Standards	IEC 60255-1
Product certifications	RCM; GL; CCC; CSA; UL; EAC; CE
Ambient temperature during storage	-40…70 °C; -40…70 °C
Operating ambient temperature	-20…50 °C at 60 Hz; -20…60 °C at 50 Hz
Relative humidity	93…97 % at 25…55 °C corresponds to IEC 60068-2-30
Vibration resistance	0.075 mm (f= 10…58.1 Hz) not in operation conforms to IEC 60068-2-6; 1 Gn (f= 10…58.1 Hz) not in operation conforms to IEC 60068-2-6; 0.035 mm (f= 58.1…150 Hz) in operation conforms to IEC 60068-2-6; 0.5 gn (f= 58.1…150 Hz) in operation conforms to IEC 60068-2-6
Shock resistance	15 Gn (duration = 11 ms) for non-operating condition corresponds to IEC 60068-2-27; 5 gn (duration = 11 ms) for operating condition corresponds to IEC 60068-2-27
Degree of protection (IP)	IP20 (terminals) conforms to IEC 60529; IP40 (housing) conforms to IEC 60529; IP50 (front plate) conforms to IEC 60529
Pollution degree	3 entspricht IEC 60664-1
Over voltage category	III corresponds to IEC 60664-1
Dielectric test voltage	2.5 kV, 1 min AC 50 Hz corresponds to IEC 60255-27
Insulation resistance	> 100 MOhm at 500 V DC
Connections - terminals	Screw terminals, 2 x 0.5 - 2.5 mm² (AWG 20 - AWG 14) solid without cable end; screw terminals, 2 x 0.2 - 1.5 mm² (AWG 24 - AWG 16) stranded with cable end; screw terminals, 1 x 0.5 - 3.3 mm² (AWG 20 - AWG 12) solid without cable end; screw terminals, 1 x 0.2 - 2.5 mm² (AWG 24 - AWG 14) stranded with cable end
[M] tightening torque	0.6…1 Nm corresponds to IEC 60947-1
Housing material	Polycarbonate
Mounting bracket	35 mm DIN rail corresponds to IEC 60715
Reliability data	MTTFd = 308.2 years; B10d = 290,000
Height	90 mm; 88,9 mm
Width	22,5 mm; 22,9 mm
Depth	73 mm; 73,7 mm
Product weight	0,11 kg; 0,11 kg
Packaging units
VPE 1 type	PCE
Number of devices per package	1
VPE 1 height	2,600 cm
VPE 1 width	8,200 cm
VPE 1 length	9,500 cm
Packaging weight (Lbs)	122,000 g
VPE 2 type	S02
VPE 2 quantity	40
VPE 2 height	15 cm
VPE 2 width	30 cm
VPE 2 length	40 cm
VPE 2 weight	5,194 kg

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