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Ground Fault Protection Family

Product Options Comparison

 

Accumetrics’ EFREM - Earth Fault Resistance Monitor, RHM - Rotor Health Monitor, and GDS - 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:

 

EFREM - Earth Fault Resistance Monitor 
AT-8000

RHM - Rotor Health Monitor 
AT-8300

GDS - Ground Detection System 
AT-8600

Monitors for Ground Fault

Yes

Yes

Yes

Monitors for Temperature (RTD's)

No

Yes

No

Current Shunt

No

Yes

No

Records Trends Over Time

Yes

Yes

No

Archiving Capability

Yes

Yes

No

Transmitter Mounting

End-of-shaft / split clamp collar

End-of-shaft

End-of-shaft

Field Voltage

Measurement Range

0–500 VDC

0–500 VDC

0–750 VDC

Maximum Transient without Damage

1000 V for 5 seconds

1000 V for 5 seconds

1500 V for 5 seconds

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

Rotor Speed

0–3600 RPM nominal; 4320 RPM max

0–3600 RPM nominal; 4320 RPM max

0–3600 RPM nominal; 4320 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

Power to Transmitter

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

Outputs

Alarm Relays; 4-20 mA; Voltage

Alarm Relays; 4-20 mA; Voltage

Alarm Relays

For more information on these systems, see Ground Fault Protection.