User Manual

3UG4.1 line monitoring relay
6.1 Application areas
3UG4 / 3RR2 monitoring relays
88 Manual, 02/2013, NEB927043002000/RS-AA/002
6.1 Application areas
Application areas
The various line monitoring relays are used, for example, in non-stationary systems such as
refrigeration containers, construction site compressors, and cranes. The devices are used in
the following application areas:
Table 6- 1 Application areas of the line monitoring relays
Function Application
Phase sequence
• Direction of rotation of the drive
• Refrigeration trucks
• Refrigerators
• Saws
• Pumps
• Rollers
• Transport of persons (elevators, moving staircases and walkways)
Phase failure
• A fuse has tripped
• Control supply voltage failure
• Cable break
• Crane systems
• Electrical welding
• Emergency generating sets (banks, hospitals, alarm systems, power
plants)
• Transport of persons (elevators, moving staircases and walkways)
Phase asymmetry
• Motor protection (overheating of the motor through asymmetric
voltage)
• Detection of asymmetric systems
Undervoltage
• Increased current on a motor with corresponding overheating
• Unintended device reset
• Mains failure – particularly with battery supply
• Heating systems
• Cranes
• Elevators
• Protection on unstable systems (switchover to emergency current,
monitoring of the generator)
Overvoltage
• System protection against destruction caused by supply overvoltages
• Energy supply to the line
• Lamps (UV lamps, laser lamps, OP lighting, tunnels, traffic lights)