Mains monitoring relays for voltage, phase loss, asymmetry and frequency

DOLD offers a broad portfolio of network monitoring relays that help protect individual system parts from damage. They monitor voltage, phase failure and asymmetry, the neutral conductor, frequency and insulation faults. Typical uses include device and system protection and the supply of safety lighting. The relays are compact and space-saving, simple to operate and flexible to apply, and they add operating reliability along with fire and accident protection.

Phase and asymmetry monitoring is covered by the BA 9040 and MK 9040N asymmetry relays, the AK 9840 for 3 AC 110 to 690 V including harmonic industrial mains, and the MH 9352/001, whose three output relays cover over- and undervoltage, phase sequence and voltage loss. Compact 17.5 mm units include the IK 9169 phase monitor and the IK 9168 and IK 9178 indicators. Phase sequence alone is checked by the BA 9041, MK 9056N, IL 9059 and OA 9059, the last two also suiting inverter supplies of 40 to 80 Hz.

For frequency, the IK 9143 and BA 9837 detect over- or underfrequency, while the MK 9837N, MH 9837 and MH 9837/5_0 measure the cycle duration for a fast reaction, with ranges of 1.5 to 200 Hz or 5 to 600 Hz; the MH 9143 targets local generator sets. Other specialists include the IL 9075 and IP 9075 fuse monitors for three-phase mains rated up to 3 AC 690 V, the IL 9069 neutral monitor and the IL 9176 undervoltage relay with test key.

• Monitors voltage, phase failure and phase asymmetry
• AK 9840 asymmetry relay, 3 AC 110 to 690 V
• MK 9837N frequency relay, 22.5 mm
• IL 9075 fuse monitor up to 3 AC 690 V
• IL 9069 detects missing or broken neutral