The DS2020DACAG2 is a next-generation AC/DC power conversion module belonging to the Power Distribution Module (PDM) series of General Electric (GE) industrial control systems. As a specific model of the DACA (AC-to-DC Converter) family, the core function of the DS2020DACAG2 is to convert 115 V or 230 V AC input power into 125 V DC output power, delivering a stable and reliable DC bus supply for GE control systems such as Mark VIe and EX2100. The module has a rated output power of approximately 1000 W, with a maximum output current of up to 9.5 A DC. It serves as a direct, form-and-fit replacement and performance upgrade for the previous generation DS2020DACAG1.
The DS2020DACAG2 is more than a simple power converter; it plays a critical role in the power supply architecture of the entire control system. When the control system uses 125 V DC as its primary power source (with or without a battery), the DACA module is responsible for converting electrical energy from the AC grid or an auxiliary AC bus into DC power. This DC output is then combined with the battery power through diode coupling, forming a highly reliable redundant DC bus. More importantly, the DS2020DACAG2 integrates a large-capacity energy storage capacitor bank, which can provide additional energy reserve during a complete loss of AC input, extending the system's ride-through time and allowing the control system to continue operating normally during a momentary power outage.
Performance Upgrades and Compatibility
The DS2020DACAG2 features two significant performance enhancements over its predecessor. First, its rated output power has been significantly increased, enabling it to supply sufficient power for larger-scale control systems. Second, and most valuably, the new module supports parallel operation—the outputs of two DS2020DACAG2 modules can be directly paralleled to provide greater total output current, with a maximum paralleled output current of up to 16.5 A DC. With the previous generation model, paralleling was not recommended due to current sharing limitations.
In terms of compatibility, the DS2020DACAG2 is a fully backward-compatible replacement for the DS2020DACAG1. All systems using the older module version can be directly upgraded without any modifications to panel wiring or mechanical mounting structures. GE recommends adopting the DS2020DACAG2 as the standard power module for all new panel designs, to fully leverage its higher power density and flexible paralleling capability.
Core Functional Features
1. Wide Range AC Input and Automatic Configuration
The DS2020DACAG2 supports two nominal AC input voltage ranges: 105 to 132 V AC (nominal 115 V AC) and 210 to 265 V AC (nominal 230 V AC). The input frequency range is 47 to 63 Hz, covering the major industrial power supply standards worldwide. Input voltage selection is accomplished through a capture cable harness inside the module: plugging the cable into connector JTX1 selects 115 V AC input, while plugging it into JTX2 selects 230 V AC input. This simple and reliable design eliminates the need for cumbersome external jumpers or switches and also prevents voltage mismatches caused by improper operation.
2. Full-Wave Rectification and High-Efficiency Filtering
The DS2020DACAG2 employs a full-wave bridge rectifier topology and an output filter capacitor bank to convert the AC input into smooth DC output. At a nominal 115 V AC input and a 9.5 A load, the output voltage is approximately 107 V DC, delivering an output power of about 1017 W. Output ripple voltage is effectively controlled to within 4 V peak-to-peak, meeting the stringent requirements of the GE control system for DC bus quality. Note that the module does not include an internal input filter; if an application has specific harmonic requirements for the power grid, the user must install an external harmonic attenuation filter on the AC input side.
3. Large-Capacity Energy Storage and Power Ride-Through
The output filter capacitors within the DS2020DACAG2 are not only used for ripple smoothing but also perform a critical energy storage function. When the AC input is completely lost, the energy stored in the capacitors can continue to power the control system for a period of time, known as the hold-up time. At a nominal 115 V AC input and a full 9.5 A load, the hold-up time for the output voltage to decay from its nominal value to 70 V DC is approximately 29.5 milliseconds. At a 132 V AC input and the same load, the hold-up time can reach 48.8 milliseconds. This feature provides a valuable transition period for the system, sufficient to ride through brief voltage dips or maintain bus voltage during battery switching.
4. Flexible Single-Module and Parallel Operation
In single-module applications, the DS2020DACAG2 can provide a maximum output current of 9.5 A DC (with an ambient temperature of -30 to 45 °C). When the load demand exceeds the rating of a single module, the outputs of two modules can be directly paralleled, with a maximum paralleled output current of 16.5 A DC. To ensure proper current sharing between the two modules during parallel operation, the following condition must be strictly observed: both modules must be connected to the same AC source to ensure completely consistent input voltages. Due to variations in open-circuit voltage and output impedance between individual modules, the output current for each module must be derated appropriately when paralleled. GE provides a probability distribution curve for system design reference and recommends retaining a 15% safety margin in parallel configurations.
5. Safe Discharge Mechanism
When power is removed for maintenance or module replacement, the output capacitors of the DS2020DACAG2 discharge automatically through the internal bleed resistor network. Under nominal input voltage, no-load conditions, the output voltage will drop to less than 50 V DC within one minute after the AC input is disconnected. Nevertheless, before any handling, a technician should always use a voltmeter to confirm that the capacitors are fully discharged, especially if a failure of the internal bleed circuit is suspected.
Installation and Replacement Procedures
The DS2020DACAG2 module features four mounting holes in its base and is secured to the floor of the control cabinet using bolts. AC input and DC output are centrally routed through a single 12-position JZ connector, which mates with the corresponding JZ2 or JZ3 connector on the Power Distribution Module (PDM).
The standard procedure for module replacement is as follows:
Remove power from the DACA module and allow at least one minute for the output voltage to discharge.
Disconnect the power input/output cable (JZ connector) on the right side of the module top.
Remove the four bolts securing the DACA module to the cabinet floor.
Remove the old module.
Note the position of the capacitor power plug on the top left side of the removed module (JTX1 for 115 V AC, JTX2 for 230 V AC).
Ensure the capacitor power plug on the new module is in the same position as the one removed.
Place the new DACA module in the same position as the one removed.
Secure the new module to the cabinet floor with the four bolts removed earlier.
Reinstall the power input/output plug (JZ connector) on the right side of the module top.
Restore power to the DACA module.
Maintenance and Troubleshooting
The DS2020DACAG2 module itself is not equipped with active diagnostic functions. Its operational status is indirectly monitored by the PPDA power diagnostic I/O pack within the PDM system: the PPDA acquires the positive and negative bus voltages relative to ground to judge whether the voltage amplitude is normal and to detect ground faults or the presence of an AC component. A DACA module failure typically manifests as a low output voltage or no output, which can be preliminarily diagnosed via the PPDA diagnostic page or PDM front panel indicators.
Common faults and possible causes:
Zero output voltage: Check whether the AC input power is normal, whether the JZ connector is firmly inserted, and whether an internal fuse is blown (if equipped).
Excessive output ripple: This may indicate aging or damage to the output filter capacitors; replacement of the module is recommended.
Overtemperature shutdown: Check whether the cabinet ventilation is obstructed and whether the ambient temperature exceeds the rated range.
The module is a non-user-serviceable design; any internal fault should be resolved by complete module replacement. Lockout/Tagout procedures must be executed before replacement, and it must be verified that all power sources connected to the DACA module are disconnected.
Application Precautions
In 240 V AC applications, special attention must be paid to preventing inadvertent cross-connections between AC supplies and the DC bus. Since most AC power supply systems have a grounded neutral, if accidental contact occurs between 125 V DC and the AC voltage, the sum of the AC peak voltage and 125 V DC will be applied to the MOVs connected between DC and ground, potentially exceeding their rating and causing damage. In 120 V AC applications, the MOV rating can withstand the peak voltage without damage. Therefore, after any maintenance work involving both AC and DC wiring, the correctness of the wiring must be carefully checked.
For parallel operation configurations, both modules must be connected to the same AC power source to ensure equal input voltages. Failure to do so will cause severe current imbalance, potentially overloading one of the modules.
