Productinformation for SUR357Z / SUR358Z

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.

Characteristics of SUR357Z / SUR358Z

Undervoltage and overvoltage monitoring for 3AC / 3NAC systems
No external supply voltage required
SUR357Z Common alarm relay for both undervoltage and overvoltage
SUR358Z Separate alarm relays for undervoltage and overvoltage

Adjustable response value
0.7…0.95 x Un / 1.05…1.3 x Un
Nominal system voltages
3AC 100 V, 110 V, 230 V, 400 V, 440 V, 500 V, 690 V
Adjustable response delay 0.5…5 s
Alarm LED
Alarm relay with two potential-free changeover contacts

Usages of SUR357Z / SUR358Z

Monitoring of the power supply of motors and electrical installations
Monitoring of loads
Switching on and switching off at a certain voltage level
Monitoring of stand-by and emergency supply systems
Supply voltage monitoring of portable loads

Optional accessories for SUR357Z / SUR358Z

Ordering information

Type	Nominal system voltage Un	Art. No.
SP100	Energy backup	B935700

Variants of SUR357Z / SUR358Z