VGM-100 Voltage & Ground Fault Monitor: 240V
Purpose‑built for mission‑critical 24‑V DC systems, the VGM‑100 offers nonstop insight into bus voltage and ground‑fault resistance across substations, switchgear rooms, and telecom sites. Its intuitive color display lets you dial in trip points, delays, and network details fast, while Ethernet/Modbus connectivity and four Form‑C outputs ensure every warning ties into SCADA, PLC, or BMS dashboards.
Installation is lightning‑quick: snap the unit onto a DIN rail or wall bracket, attach two sensing leads to the 24 V battery line, and power it from that same circuit—no external supply required. Engineered to IEEE/ANSI C37.90a noise‑immunity standards and rated 0‑55 °C, the VGM‑100 maintains accuracy even in demanding utility environments.
When you need rock‑solid protection and real‑time data at an affordable price, the VGM‑100 delivers—minus the headaches of larger, complex monitoring systems.
- Color touchscreen simple interface
- Ethernet connectivity to web interface, (4) Form C Contacts
- Modbus TCP/IP output for all measured parameters
- Simple installation with mounting kit for DIN rail or wall mount
- Monitors 24V batteries
- Configurations available for different needs
| Measurement Range | Battery Voltage: 180-320 Fault Resistance Limit Set: 1 – 100 kΩ |
| Fault Resistance Limit Set | 1 – 100 kΩ |
| Output Contacts | (4) Form C |
| Contact Rating | 125 VAC/VDC: 0.5 A 30 VDC: 2 A |
| Maximum Switching Power | 60 W |
| Power Requirements | Powered by connected battery DC voltage |
| Noise Immunity | IEEE/ANSI C37.90a‑1989 compliant |
| Time Delay to Alarm | Adjustable 1 – 999 seconds |
| Operating Environment | Temp 0 – 55 °C (32 – 131 °F); Humidity 0 – 95 % RH |
| Dimensions / Weight | 147 × 91 × 45 mm (5.77 × 3.56 × 1.77 in) / 284 g (10 oz) |
Product Literature
Support Documents
How does the VGM detect ground fault conditions?
DC ground fault detection is determined by measurement of the voltage imbalance relative to ground. These measurements are made through very high resistance divider networks. One establishes the ground reference, and the other measures the positive and negative DC voltages. These values are applied to analog‑to‑digital converters, and the microcontroller firmware compares the sum of these DC values to the ground reference. If the sum is 0, the DC voltage is perfectly balanced relative to ground. If the sum is positive or negative, the DC voltage is unbalanced positive or negative. User settings determine the extent of imbalance that will result in an alarm condition.
Will the VGM detect a ground fault via a leaked battery jar?
The system will detect a ground fault caused by a leaking battery jar provided the ground‑fault‑resistance setting is configured correctly. Because a leak creates a resistive path to ground, the VGM senses the resulting voltage imbalance and triggers an alarm as long as the path‑to‑ground resistance is lower than the set threshold.
What is the k ohm limit for ground detection?
Up to 300 kΩ.
What are the contact ratings for the Form C contacts?
The relays are rated at 60 W with a maximum of 220 V DC and 2 A. Practically, they can switch 2 A at 30 V DC or less, 0.5 A at 125 V DC, and only 0.009 A at 220 V DC. Use an external relay if higher ratings are required.
Do the connections between the monitor and the batteries need to be fused?
No. The monitor includes an internal fuse for self‑protection. You may still choose to fuse the external wiring to guard against short circuits.
Is the VGM CSA certified?
The VGM‑Series is CE certified. For Canadian customers, CSA certification is not required for DC‑powered units. Contact Eagle Eye for clarification on specific certification needs.