HYDRA

Service Manual

2A-23.Power Supply Circuit Description

The Hydra power supply consists of three major sections:

∙Raw DC Supply

The raw dc supply converts line voltage (90V to 264V ac) to a dcoutput of 7.5V to 35V.

∙5V Switcher Supply

The 5V switching supply regulates the 7.5 to 35V dc input to anominal 5.0V ±0.25V dc (VCC).

∙Inverter

Using the 5V switching supply output, the inverter generates the -30Vdc, -5V dc, and 5.4V ac supply levels needed for thevacuum-fluorescent display and the RS-232 Interface. The inverteralso provides isolated +5.3V (VDD), +5.6V (VDDR), and - 5.4V (VSS)outputs for the inguard circuitry.

2A-24.Raw DC Supply

The raw dc supply circuitry receives input from power transformer T401, which operates on an input ranging from 90V to 264V ac. The power transformer is energized whenever the power cord is plugged into the ac line; there is no on/off switch on the primary side of the transformer. The transformer has an internal 275V ac metal-oxide varistor (MOV) to clamp line transients. The MOV normally acts as an open circuit. When the peak voltage exceeds approximately 400V, the line impedance in series with the line fuse limits transients to approximately 450V. All line voltages use a slow blow 0.125 A, 250V fuse.

On the secondary side of the transformer, rectifiers A1CR2, A1CR3, and capacitor A1C7 rectify and filter the output. When it is ON, switch A1S1 (the front panel POWER switch) connects the output of the rectifiers to the filter capacitor and the rest of the instrument. Depending on line voltage, the output of the rectifiers is between 7.5 and 35V dc. Capacitor A1C2 helps to meet electromagnetic interference (EMI) and electromagnetic compatibility (EMC) requirements.

When external dc power is used, the power switch connects the external dc source to power the instrument. The external dc input uses thermistor A1RT1 (for overcurrent protection) and diode A1CR1 (for reverse input voltage protection.) Capacitor A1C59 helps meet EMI/EMC requirements. Resistor A1R48, capacitors A1C2 and A1C39 also ensure that the instrument meets EMI/EMC performance requirements.

2A-25.Auxiliary 6V Supply

Three-terminal regulator A1U19, voltage-setting resistors A1R44 and A1R46, and capacitor A1C34 make up the auxiliary 6-volt supply. This supply is used for the inverter oscillator, inverter driver, and the power fail detection circuits.

2A-26.5V Switcher

The 5V switcher supply uses a switcher supply controller/switch device A1U9 and related circuitry.The 7.5V dc to 35V dc input is regulated to 5.1V dc (VCC) through pulse-width modulation at a nominal switching frequency of 100 kHz.

2A-8

Page 89 Page 91
Page 90
Image 90
Fluke 2635A, 2625A service manual 2A-23.Power Supply Circuit Description, 2A-24.Raw DC Supply
Page 89 Page 91

2635A, 2625A specifications

The Fluke 2625A is a sophisticated data logger designed for a wide range of industrial and laboratory applications. This versatile instrument excels in capturing and monitoring temperature and voltage measurements with precision and reliability. One of its standout features is its ability to record data from various sensors, making it ideal for environments where comprehensive data acquisition is critical.

Equipped with a large LCD display, the Fluke 2625A provides clear and user-friendly access to real-time measurement data. Its graphical interface allows users to visualize trends and monitor readings easily, which significantly enhances usability. The device supports a variety of input types and can connect to thermocouples, RTDs, and other sensors, offering great flexibility for various measurement tasks.

The Fluke 2625A employs advanced measurement technologies that ensure accuracy in data logging. With a high sampling rate, it captures fast-changing signals while maintaining data integrity. The device features a built-in memory that allows for extensive logging, accommodating long-term monitoring tasks without requiring constant oversight. Users can set it to log data at specified intervals, offering customizable solutions for different monitoring needs.

Another significant characteristic of the Fluke 2625A is its robust communication capabilities. The device supports USB and RS-232 interfaces for easy connectivity with computers and other devices, making data transfer and analysis seamless. This feature is especially beneficial for users who need to compile or analyze large sets of data quickly.

Furthermore, the Fluke 2625A is designed with durability in mind. Its rugged construction makes it suitable for challenging environments, including those with high levels of vibration, dust, or moisture. This reliability ensures that the device can withstand the rigors of fieldwork while still delivering accurate measurements.

In summary, the Fluke 2625A is a powerful data logger that combines versatility, accuracy, and reliability. Its user-friendly interface, advanced measurement technologies, and robust design make it an essential tool for professionals in various industries, from manufacturing and HVAC to research and development. Whether monitoring temperature changes in a laboratory or assessing voltage levels in an industrial setting, the Fluke 2625A stands out as a trusted solution for effective data logging and analysis.
Top Page Image Contents