[Amps] What causes arc over on the BeO2 ceramic insulator ofan 8877?

[Carl]

Very few tubes use BeO2 and that includes the pink ceramic. It is just 
another ham myth.
Those tubes that do use it are not dangerous unless you start grinding it.

BeO2 is used as the insulator between conduction cooled tubes and their heat 
sink.

Arcing on a ceramic tube can be caused by contanimation on the suface 
deposited on the ceamic by electrostatic means. It is similar to the way HV 
cables attract dust such as on CRT's.

A regular PM schedule of cleaning insulators, tube fins and blower impellers 
in a dusty enviroment will extend tube life.

Carl
KM1H



----- Original Message ----- 
From: "peter chadwick" <g8on at fsmail.net>
To: "John Farber" <kg6i at comcast.net>; <amps at contesting.com>
Sent: Saturday, August 31, 2013 4:12 AM
Subject: Re: [Amps] What causes arc over on the BeO2 ceramic insulator ofan 
8877?


> John,
>
> Are you sure the ceramic insulator in an 8877 is BeO2? It is not mentioned 
> in the data sheet, and generally, where BeO2 is used, the fact is 
> mentioned because of the problems of dust.
>
> 73
>
> Peter G3RZP
>
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