Accumetrics’ Earth Fault Resistance Monitor, Rotor Health Monitor, and Rotor Ground Detection System offer superior ground fault protection of motors and generators. Systems monitor for insulation faults on the field windings of generators and synchronous motors with brushless exciters. They employ advanced wireless techniques to transmit measurement data from the rotor to a stationary receiver unit.
Accumetrics’ Ground Fault Detection Systems are in a class of their own. They provide immediate notification of field ground faults, reducing the risk of prolonged and costly unscheduled outages.
The product line includes three monitoring and detection options designed to retrofit existing generators, plus Accutector, a drop-in replacement for obsolete Rotector Rotor Ground Fault Monitoring Systems with enhanced durability and diagnostics.
| Earth Fault Resistance Monitor AT-8000 | Rotor Health Monitor AT-8300 | Ground Detection System AT-8600 | Accutector Ground Fault Monitoring System AT-9000 (replaces Rotector Model AS-9000) | ||
| Monitors for Ground Fault | Yes | Yes | Yes | Yes | |
| Monitors for Temperature | No | Yes (12/24 RTDs) | No | Yes (2 TCs) | |
| Current Shunt | No | Yes | No | Yes | |
| Records Trends Over Time | Yes | Yes | No | Yes | |
| Archiving Capability | Yes | Yes | No | Yes | |
| Transmitter Mounting | End-of-shaft / split clamp collar | End-of-shaft | End-of-shaft | Paddle Style | |
| Field Voltage | Measurement Range | 0–500 VDC | 0–500 VDC | 0–750 VDC | 0–500 VDC |
| Maximum Transient without Damage | 1000 V for 5 seconds | 1000 V for 5 seconds | 1500 V for 5 seconds | 1000 V for 60 seconds 2000 Vpeak for 1 second | |
| Environment | Ambient Temperature | 32–185 °F / 0–85 °C at Rotor Module; 32–122 °F/0–50 °C at Receiver Unit | 32–185 °F/0–85 °C at Rotor Module; 32–122 °F/ 0–50 °C at Receiver Unit | -40–194 °F/-40–90 °C at Rotor Module; -40–140 °F/-40–60 °C at Receiver Unit | -4 °F to +158 °F /-20 °C to +70 °C |
| Rotor Speed | 0–3600 RPM nominal; 4320 RPM max | 0–3600 RPM nominal; 4320 RPM max | 0–3600 RPM nominal; 4320 RPM max | 0–1800 RPM nominal; 2350 RPM max | |
| Receiver Power | 85–250 VAC 50/60Hz or 125–375 VDC <20W | 85–250 VAC 50/60Hz or 125–375 VDC <20W | 100–240 VAC 50/60 Hz or 24 VDC | 100-240 VAC 50/60Hz, 0.5 A | |
| Power to Transmitter | Induction | Induction | Induction | Induction | |
| Machine Connections | Positive Field Voltage; Negative Field Voltage; Rotor Ground | Positive Field Voltage; Negative Field Voltage; Rotor Ground; Channel 1 Shunt current + and -; Channel 2 Shunt current + and -; RTDs | Field Negative Terminal; Rotor Ground | Field Positive Terminal; Field Negative Terminal; Rotor Ground; 3x Current Shunt Resistors; 2x Thermocouples | |
| Outputs | Alarm Relays; 4-20 mA; Voltage | Alarm Relays; 4-20 mA; Voltage | Alarm Relays | Modbus TCP | |
| Hazardous Locations | N/A | N/A | N/A | Class I, Division 2 Groups A, B, C, and D, T3C | |
For more information on these systems, see Ground Fault Protection.
