practical high voltage power supplies ian white, gm3sek click to step through the presentation

Practical High Voltage Practical High Voltage Power SuppliesPower Supplies

Ian White, GM3SEKIan White, GM3SEK

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Practical High Voltage PSUs

• Safety + Reliability

• Practical circuits and components

Safety + Reliability

Thousands of amateurs use HV safely,every day.

So can you!

But your first big mistake will be your last, so…

Always think about what you’re doingand you’ll be fine.

DON’T MAKE MISTAKES!

Safety + Reliability

Good safety habits:

• Multiple barriers against failures and accidents.

• NEVER be only one fault away from danger.

• ALWAYS unplug from the mains.

• ALWAYS discharge HV circuits before touching.

• Multiple earth bonding – very important.

• ALWAYS be thinking what could possibly go wrong…

and then prevent it!

1. Defence in Depth.

Safety + Reliability

Good safety habits:

1. Defence in Depth.

2. Build safety into hardware. • Don’t rely on ‘being careful’… because one day you will drop your guard.

• Use good quality components and construction.

• Greatest risk when testing and repairing.

Use safety covers inside (clear acrylic sheet).

Safety + Reliability

Make these into your way of life:

1. Defence in Depth.

2. Build safety into the hardware.

3. Don’t ever stop thinking!

Safety + Reliability

Reliability – for DX and contesting

Building reliability into the hardware: • Good quality components and construction.

• Under-run all components.

• Check all component ratings.

• Use cooling fans.

Practical High Voltage PSUs

Safety + Reliability

• Practical circuits and components

Circuits and Components

Circuits and Components

Mains

Circuits and Components

Transformer

Circuits and Components

Rectifiers + capacitors

Circuits and Components

HV+ output

Circuits and Components

HV-minus return

Circuits and Components

Mains

Circuits and Components

Circuits and Components

Transformer

Circuits and Components

Transformer

Circuits and Components

Transformer

Circuits and Components

Transformer

Circuits and Components

Circuits and Components

Circuits and Components

Circuits and Components

Rectifiers + capacitors

Bridge rectifieris best!

About 30uF

Circuits and Components

HV+ output

Surge limitingresistor

(“Glitch resistor”)

HV socket

• Coaxial

• SAFE connector!

• Earth bonding

Circuits and Components

HV-minus return

Why a separateHV-minus return?

Chassis earthChassis earth

Circuits and Components

HV-minus return

Anode current

Anode current

Grid current

Circuits and Components

HV-minus return

5-pin XLR socket:

• HV-minus (duplicated)

• Earth (duplicated)

• HV control input

• Connector shell also earthed. Important safety precautions.

HV won’t turn on unless this is plugged in.Chassis earth

Circuits and Components

Practical High Voltage PSUs

Safety + Reliability

Practical circuits and components

For more details…

• Radcom January-February-March 2009

• The ‘In Practice’ website:http://tinyurl.com/inpractice

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