Key Features
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High-Voltage Signal Attenuation – Scales field bus voltages from 125 VDC to 1000 VDC down to safe ±50 VAC square wave signals
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Integrated Ground Detection Front-End – Provides the high-voltage interface for the excitation circuit ground detection system
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PPT Voltage Range – Accepts power potential transformer voltages from 120 VAC to 1300 VAC RMS
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Jumper-Selectable Filtering – JP1 and JP2 jumpers select capacitance for PPT voltages below or above 750 VAC RMS
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Redundant Test Signal Source – Supports M1 or M2 controller switching for simplex and redundant (TMR) systems
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Alterrex Compatibility – Requires dual EXAM configuration for Alterrex applications
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Robust Industrial Design – Built for harsh power generation environments with high-voltage isolation
Technical Parameters
Core Advantages
1. Critical High-Voltage Interface
The IS200EXAMG1B is the essential protective barrier between the generator’s lethal excitation circuit and the sensitive ground detection electronics. Raw field voltage sitting at 800 VDC cannot be directly connected to standard control cards—doing so would destroy the EGDM and create a fire hazard. The EXAM module acts as a “sacrificial” high-voltage front-end, safely scaling these dangerous voltages down to harmless ±50 VAC signals .
2. Precision Signal Conditioning
The module uses a precision voltage divider and signal conditioner architecture. Its “G1B” suffix indicates enhanced trace routing and improved EMI filtering compared to earlier revisions, delivering better performance in electrically noisy switchgear compartments. This ensures the EGDM receives clean, accurate signals for reliable ground fault detection .
3. Essential for Complete Ground Detection Chain
The EXAM and EGDM modules are interconnected via the Excitation Power Backplane (EPBP), together forming a complete protection chain. The EXAM provides the high-voltage front-end attenuation, while the EGDM performs the low-voltage measurement and ground fault determination. Both modules are indispensable for the excitation ground detection system to function .
4. Seamless System Integration
The IS200EXAMG1B integrates directly into the GE EX2100 / EX2100e architecture, mounting in the High Voltage Interface (HBI) module within the auxiliary cabinet. It connects via a single 9-pin cable to the EPBP, with EGDM modules plugging into the same backplane. This streamlined interconnection simplifies installation and maintenance .
Applications
The GE IS200EXAMG1B is deployed in critical power generation and industrial applications:
Primary Functions
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High-Voltage Attenuation – Scales field bus voltages to safe measurement levels
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Signal Injection – Applies low-frequency square wave to excitation winding electrical center
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Sense Resistor Interface – Reads voltage across EGDM sense resistor for ground path calculation
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Redundant Source Switching – Supports M1/M2 master selection for TMR systems
Recommended Models & Related Products
Note: The EXAM and EGDM modules work as a matched pair—both are required for a functioning excitation ground detection system. Verify your system configuration (simplex vs. TMR, Alterrex vs. standard) before ordering .
What's Included
Note: EGDM ground detector module, EPBP backplane, cables, and system software are sold separately.
Why Buy From Us?
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In Stock – Ready to ship same/next business day
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Fully Tested – Each unit verified for functionality
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Warranty Included – Purchase with confidence
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Technical Support – Compatibility assistance available
Frequently Asked Questions (FAQ)
Q1: What is the GE IS200EXAMG1B?
It is an Exciter Attenuation Module (EXAM) for GE’s EX2100 / EX2100e excitation control systems. It provides the high-voltage front-end interface for the excitation circuit’s ground detection system, attenuating lethal field voltages to safe levels for the EGDM ground detector module .
Q2: What is the difference between IS200EXAMG1B and IS200EXAMG1A?
The G1B is a hardware revision upgrade over the G1A. It features optimized resistors/capacitors/varistors for higher voltage withstand and noise immunity, added M1/M2 redundant signal source switching, and improved accuracy (≤±0.1% vs. ±0.2%). The G1B is fully compatible and can directly replace the G1A .
Q3: What are the input voltage ranges for this module?
The field voltage (Vbus) range is 125 VDC to 1000 VDC. The power potential transformer (PPT) voltage range is 120 to 1300 VAC RMS .
Q4: What is the function of the JP1 and JP2 jumpers?
JP1 and JP2 select the filter capacitance based on the PPT voltage level. There are two options: one for PPT voltages below 750 VAC RMS, and another for PPT voltages in excess of 750 VAC RMS .
Q5: What happens if the jumpers are configured incorrectly?
Incorrect jumper settings are a common field error. If attenuation is set too high, the EGDM cannot correctly identify the square-wave signal, triggering a continuous ground fault alarm. Always measure the actual PPT operating voltage with a True-RMS multimeter before configuring the jumpers .
Q6: Does this module work in redundant (TMR) systems?
Yes. The IS200EXAMG1B supports both simplex and triple modular redundant (TMR) applications. In TMR systems, a single EXAM module works with three EGDM modules (Controller, Master 1, Master 2), with M1/M2 source switching handled automatically .
Q7: What is the Alterrex configuration?
For Alterrex excitation systems, two EXAM modules are required—one for the generator field and one for the exciter field—working in tandem .
Q8: Where is the EXAM module mounted?
It mounts inside the High Voltage Interface (HBI) module, located in the auxiliary cabinet of the EX2100 system .
Q9: Does the module have any diagnostic indicators?
No. The EXAM is a blind module with no test points, fuses, or LED indicators. Diagnostic information is provided through the EGDM module status .
Q10: What is the isolation rating?
The module provides 2.5 kVrms input-to-output isolation, meeting the floating ground requirements of the excitation system .
Q11: What is the country of origin?
United States (USA) .
