The GD30FDC is a 12-42V Direct Current Compressor designed for cooling appliances in various mobile applications, such as trucks, caravans, boats, and cars. It is also suitable for medical appliances in ambulances. This compressor operates with the environmentally friendly refrigerant R134a and is built to be compact, highly reliable, and efficient, even at tilt angles up to 30°. Its design is based on ACC's "D" series, which has a proven track record since 1984.

Function Description:

The GD30FDC compressor is powered by a dedicated electronic driver, FDC1, which allows it to operate within a wide DC voltage range of 12V to 42V. The FDC1 driver automatically adjusts to the power supply voltage and incorporates comprehensive protection features for both the battery and the compressor motor. It is designed for capillary tube expansion systems.

The electronic control unit FDC1 is equipped with an exclusive Serial Port Interface (SPI) with an RJ11 connector. This SPI allows for programming the electronic driver using a dedicated software package provided by ACC. It also facilitates communication with an Electronic Integral Manager (EIM) of the appliance, enabling the compressor to operate in slave mode.

The FDC1 driver includes "Smart Speed®" as a programming option, which is a plug-in system that automatically adapts the compressor speed to the current thermal load. This feature minimizes thermostat cycles by optimizing compressor speed, extending on-time, and significantly reducing start/stop energy losses. Lower speeds lead to higher evaporating temperatures, better Coefficient of Performance (COP), and reduced energy consumption. During pull-down, the compressor operates at maximum programmed speed for quick cooling. Smart Speed® requires no specific design parameters for the compressor or appliance, making it easy to integrate.

Another programming option is "Sleep and Sleep Energy Saving," specifically designed for mobile air conditioners. In Sleep mode, the compressor runs for four hours after start-up, with speed limits set by a fixed programmed value or available battery voltage, or external switching. In Sleep Energy Saving mode, the compressor runs at maximum programmed speed for the first hour to provide high cooling capacity, then progressively lowers its speed to a minimum of 1,500 rpm over the next three hours, balancing comfort and energy efficiency.

The GD30FDC boasts a low starting capability, operating effectively at voltages as low as 10V under balanced pressure conditions. It can also handle some remaining differential pressure when the thermostat off-time is unusually short. To further enhance starting capability, the FDC1 driver includes a 3-minute minimum thermostat off-time, which can be disabled if not required. A 1-second filter at the thermostat input prevents incorrect operation due to micro-switching caused by vibrations, eliminating the need for analogical filtering.

Usage Features:

The compressor's operation can be configured in various running modes:

Standard mode: The compressor runs at a fixed programmed speed or at a speed externally switched between programmed minimum and maximum values in four steps. The speed can be limited by the available battery voltage, with 1,500 rpm at cut-in voltage and programmed fixed speed at or above maximum nominal voltage. This mode is particularly useful for eutectic plates systems.
Smart Speed® mode: The compressor operates at variable speed to achieve optimal performance based on the thermal load. The speed can be limited by a fixed programmed value, available battery voltage, or external switching.
Sleep mode: The compressor runs for four hours after start-up. Speed can be fixed or externally switched.
Sleep Energy Saving mode: The compressor runs for four hours, starting at maximum programmed speed for the first hour and gradually decreasing to 1,500 rpm over the next three hours.
Slave mode: In this mode, the variable speed is controlled by an Electronic Integral Manager (EIM) connected to the FDC1 driver via SPI. The EIM monitors internal appliance temperature, compares it with the set point, and determines compressor operation and speed. It can also record and display abnormal events.

The FDC1 driver's terminal board facilitates all connections, including battery power, fan, and thermostat. For optimal performance and reliability, adequate heat removal from both the electronic driver and the compressor is crucial. Free air circulation over these components must always be ensured. The recommended cooling method (static or fan) depends on compressor speed and evaporation temperature, with condensation temperature being a secondary factor.

Maintenance Features:

The GD30FDC is electronically protected against a range of malfunctions and failures:

Battery discharge: The system prevents compressor operation if the battery voltage drops too low. The battery protection level can be programmed or set externally via SPI connections.
Fan overcurrent: Protects the compressor and driver from excessive fan current due to overload or short-circuit.
Starting failure: If the desired running speed is not reached during start-up, the unit stops and retries after one minute.
Compressor overload: This protection activates if the compressor speed falls below the set speed or if the current draw is excessive, preventing damage from refrigerating overload or compressor failure.
Electronic driver overheat: An internal sensor stops the unit if the electronic components' temperature becomes too high.

In case of an alarm, the system attempts to restart the compressor automatically. For most alarms, there are ten automatic restart attempts. For battery protection alarms, the number of attempts is unlimited. If the sequence of automatic attempts is exhausted, the unit remains off until manually reset by switching the power supply off and on. Thermostat intervention during restart attempts interrupts and resets the sequence.

The SPI can be configured to connect an LED that displays alarm interventions and identifies their cause through a sequence of flashes. Each flash sequence corresponds to a specific alarm type (e.g., 1 flash for battery protection, 2 for fan overcurrent, 3 for starting failure, 4 for compressor overload, 5 for electronic driver overheat, 7 for internal error). If the FDC1 driver is connected as a slave to an EIM, a digital alarm code is transmitted to the EIM for display and action.

Proper wiring is essential for reliable operation. The compressor must always be powered through the FDC1 driver, and direct connection to a battery or AC source is strictly prohibited. The FDC1 driver should not be replaced with any other electronic driver. Correct battery polarity must always be observed. Fuses are required between the positive battery terminal and the positive power input terminal of the electronic driver, with specific amperage ratings for 12V, 24V, and 42V systems. To prevent excessive voltage drop, the length and cross-section of power leads must be chosen according to specified guidelines. Any connectors or switches in the power path should have a resistance less than 10mΩ to avoid issues.

ACC GD30FDC - Page 19

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