VARIMETER IMD insulation monitoring devices for unearthed IT power systems

In an unearthed power supply, known as an IT system, an insulation monitoring device (IMD) continuously measures the insulation resistance of the network against earth. Use of an IMD in IT systems is required under the "Safety of Machinery" standard. The goal is to stop insulation faults from turning into accidents, equipment failures or fires, while giving maintenance staff warning before a fault takes the system down.

DOLD's VARIMETER IMD devices are offered for DC, AC and three-phase networks as well as mixed AC/DC supplies. Typical applications include monitoring loads while they are switched off, mobile power generation, eMobility and DC networks, and medically used rooms. Because they can check drive components even when idle, they help prevent unplanned drive failures that would otherwise stop a machine or a whole plant.

For electric vehicle charging, the RN 5897/020 is designed for DC charging stations under IEC/EN 61851-23. During charging, the station and vehicle form an unearthed DC system with voltages up to 1000 V, and the IMD supervises insulation from the charger right into the vehicle so the user is never exposed to that voltage.

• For DC, AC, three-phase and mixed AC/DC IT systems
• RN 5897/020 for DC charging stations per IEC/EN 61851-23
• Monitors switched-off loads and idle drive components
• Suited to mobile generation, eMobility and medical rooms
• Early fault detection improves fire safety and uptime