PH28
AIRBORNE REGULATED AC TO DC CONVERTER
(115V/400Hz to 4-28 Vdc Output)
The PH28 is a pulse width modulated ac to dc power converter that provides regulated 4-28 Vdc output with up to 10 amperes continuous output current. This converter is primarily designed for 115V/400 Hz aircraft systems to deliver variable 4 to 28 Vdc power to incandescent lamps or LED loads for airborne/ground instruments, navigation and electronic systems. The unit can also be used as a fixed output voltage source between 14 Vdc and 28 Vdc.
The DC output is factory calibrated to 28 Vdc at the receptacle for a 10 amp load. The output voltage level is controlled manually by the duration of grounding the Dim or Bright control pin through an external momentary On-Off toggle switch.
Specifications
115 Vac, 380 Hz to 800 Hz
105 Vac to 125 Vac
95 Vac to 130 Vac
3.6 Amps typical at 115 Vac & at FL, .4 Amps @ NL
4-28 Vdc regulated - Grounding Pin G (Up) or Pin A (Down)
10 Amps continuous
15 Amps intermittent
Regulation
2% for load, 1% for line and 2% for temperature
Response Time
10mSec typical
Overload (OL
Deliver 110% output power for 2 hours
Thermal
The unit shuts down for thermal overload exceeding 105 °>C temperature inside
Protection (OL)
Withstands without damage or degradation load exceeding 110% to an output short circuit. Unit delivers rated output power upon removal of the overload condition
Protection (SC)
Under a output short circuit condition, the input and output currents pump and the currents are limited to safe values.
Control
The output voltage is increased by grounding pin G and decreased by grounding pin A. When the ground is removed (OFF) the output voltage stops changing. The total time it takes from BRT to DIM (or DIM to BRT) using a continuous grounding is about 7 seconds. For faster and smoother control, apply grounding On and Off at appropriate rate by hand until a desired brightness or dimming is obtained. A minimum duration of one millisecond grounding is required to advance the output voltage one increment. There are total of 64 increments from full bright to dim or dim to full bright. (See Output Voltage Control Graph)
Efficiency
85% Typical
Temperature
-55° C to +71° C
Altitude
55,000FT
Cooling
Forced air cooling (fan used) and thermal conduction through bottom plate
Finish
Gold iridite per MIL-C-5541 & black paint
Weight
3.5 LBS (1.59 kg)
Size
4.30 W x 6.87 L x 2.75 H inches Less protrusion of connector and screw 109.2 W x 174.6 L x 69.9 Hmm heads
Environmental
By test, design similarity and/or design analysis per:
RTCA DO-160D F2VBBB[STX]EWXDFSAEAZZRL[XXC1]XXA
