[Amps] SB 220 Exploding Resistor

[John Lyles]

If you get a strong enough wirewound resistor, this can suffice as the 
surge current limiting resistor for a spark over in a tube. With 250 
amps at the beginning of the overcurrent (2500 V/10 ohms) spike, there 
is enough magnetic field to break a wirewound R as the windings have 
mechanical force between turns. I have always used bulk carbon for 
series R, like Kanthal Globar makes. They are exactly the right part for 
this.

http://www.globar.com/ec/bulk-ceramic-resistors/globar-bulk-ceramic-non-inductive-resistor-applications.html

http://www.globar.com/ec/bulk-ceramic-resistors/axial-leaded-resistors.html

Finding them through distribution might be a problem, though. Has anyone 
else used these?

John
K5PRO


> Date: Sun, 17 Jan 2016 13:19:20 -0500
> From: "Carl" <km1h at jeremy.qozzy.com>
> To: "Tom Hellem" <tom.hellem at gmail.com>,	<Amps at contesting.com>
> That blown resistor may have been underated and blew during a tube arc. The
> idea of a surge suppressor is to not fail and allow the milliseconds for a
> fuse/breaker to open.
> A 10-15 Ohm 20-25W Real wirewound resistor will cure that problem. Look for
> Vitreous Enamel in the description.
> Carl
> KM1H