The voltage relays of the VME420 series are designed to monitor the frequency, undervoltage, overvoltage and the voltage between two threshold values (window discriminator function) in AC and DC systems. The voltages are measured as r.m.s. values. The currently measured value is continuously shown on the LC display. The measured value leading to the activation of the alarm relays will be stored.

The voltage relays of the VME421H series are designed to monitor the frequency, undervoltage, overvoltage and the voltage between two threshold values (window discriminator function) in AC and DC systems. The voltages are measured as r.m.s. values. The currently measured value is continuously shown on the LC display. The measured value leading to the activation of the alarm relays will be stored.

Relays of the SUA143 series are designed for voltage monitoring in single-phase AC or DC systems. The devices can be used for undervoltage or overvoltage monitoring. External supply voltage is not required.

Relays of the SUA145 series are designed for voltage monitoring in single-phase AC or DC systems. The devices can be used for undervoltage or overvoltage monitoring. External supply voltage is not required. The values for voltage, hysteresis and response delay are set via potentiometers.

Relays of the SUA200 series are designed to monitor the voltage in single-phase AC or DC systems. The devices are suitable for undervoltage and overvoltage monitoring (window discriminator function). External supply voltage is not required. The response values for undervoltage and overvoltage are individually adjustable.

The multi-functional voltage relays of the VMD420 series are designed to monitor the frequency, undervoltage and overvoltage and the voltage between two threshold values (window discriminator function) in 3(N)AC systems. The voltages are measured as r.m.s. values. The currently measured value is continuously shown on the LC display. The measured value leading to the activation of the alarm relays will be stored.

The multi-functional voltage relays of the VMD421H series are designed to monitor the frequency, undervoltage and overvoltage and the voltage between two threshold values (window discriminator function) in 3(N)AC systems. The voltages are measured as r.m.s. values. The currently measured value is continuously shown on the LC display. The measured value leading to the activation of the alarm relays will be stored.

The undervoltage relays of the SUD140 series are designed to monitor three-phase AC systems with N conductor for undervoltage. External supply voltage is not required. The response value is set via a potentiometer.

The voltage relays of the SUD142 series are designed to monitor three-phase AC systems without N conductor for undervoltage. . External supply voltage is not required. The response value is set via a potentionmeter.

The voltage relays of the SUD472 series are designed to monitor the voltage of three-phase AC systems without N conductor. The devices can be used for undervoltage or overvoltage monitoring. External supply voltage is not required. The response values are set via potentiometers. An integrated energy backup maintains the power supply for five seconds.

The voltage relays of the SUD473 series are designed to monitor the voltage of three-phase AC systems with N conductor. The devices can optionally be used for undervoltage or overvoltage monitoring. External supply voltage is not required. The response values are set via potentiometers. An integrated energy backup maintains the power supply for five seconds.

The relays of the SUR353Z series are designed to monitor the voltage of three-phase AC systems. Neutral conductor connection is not required, hence the relays are suitable for 3AC and 3NAC systems. External supply voltage is not required.

The relays of the SUR357Z/358Z series are designed to monitor the voltage of three-phase AC systems. The relays can be used for both undervoltage and overvoltage monitoring (window function). Neutral conductor connection is not required, hence the relays are suitable for 3AC and 3NAC systems. Supply voltage and measuring voltage are galvanically separated. Special input transformers attenuate interferences from the system. The devices include an input circuit protection.

The relays of the SUG140 series monitor the undervoltage in a DC system. External supply voltage is required. Response value, response delay, and hysteresis are adjustable.

The relays of the SUG141 series are designed to monitor the overvoltage in a DC system. External supply voltage is required. Response value, response delay and hysteresis are adjustable.