HeyBub wrote:
wrote:
Intermatic surge protectors do not use MOVs - they are electronic.
What is this claim based on? If they don't use MOV's what exactly
do they use? Also, this would seem to imply that MOV's are not
considered electronic components, but I believe by any reasonable
definition, they are electronic components.
You're right, of course. MOV are classified as "electronic"
components. But metallic-oxide-varistors work like reverse fuses:
they short their terminals together. And, like fuses, they (usually)
only work once with no indication (other than sometimes smoke) that
they won't work again.
Sophisticated electronic circuitry can bleed off surges to ground and
continue to function indefinitely. It is the existence of this
circuitry that's the difference between a $3.00 "surge-suppression"
outlet strip and a $50.00 one.- Hide quoted text -
- Show quoted text -
I think I've answered the question myself. Below is an excerpt from
Intermatics datasheets from both a residential and also a commercial/
industrial unit that clearly say both do in fact use MOV's and say
nothing about any alternate "sophisticated electronic circuitry." I
don;t know of any such alternate components that can handle the huge
currents that MOV's can which is why they are used in all the surge
protectors that I've seen.
If you have any alternate reference, we'd like to see it.
Residential:
Features and Applications:
The IG1240RC features six modes of protection and is recommended for
residential and light commercial applications.
It is intended for installation on 120/240 volt AC panels. The
IG1240RC incorporates the newest developments in MOV
technology and provides individual component thermal protection and
monitoring.
Commercial:
For installation in Category "C & B" locations
! Service Entrance, Distribution Panels and Sub-panels
! Parallel installation
! 125k Amps Peak Surge Capacity per mode
! All mode suppression for systems with a neutral
! Line-to-Line, Line-to-Neutral, Line-to-Ground, Neutral-to-Ground
! 6 mode suppression for systems with no neutral
! Line-to-Line, Line-to-Ground
! Integral Disconnect Switch with safety interlock
! Easily replaceable master surge module
! 40k Amp MOVs
! 200k AIC Surge Rated Fuses
Ah, okay. Thanks for the info. I thought a quality company like Intermatic
would rely on something other than MOVs, such as zener diodes or
gas-discharge tubes. Maybe even motor/alternators.
If they, in fact, are relying on piece-of-**** MOVs (probably made in
China), well, might as well stand naked in the rain.
According to the IEEE guide, "the vast majority (90%) of both
hard-wired and plug-in protectors use MOVs to perform the
voltage-limiting function. In most AC protectors, they are the only
significant voltage limiters."
Zener diodes and gas discharge tubes don't have the energy dissipation
capacity of MOVs in a small volume. MOVs dissipate the energy throughout
the volume of the device, where a zener diode dissipates the energy at a
'junction'. Other devices with high capacity are arc gaps and silicon
carbide devices (another form of MOV). I don't see a practical component
solution in your list.
You have not said why MOVs are a POS.
You could certainly use a motor/alternator. Depending on how much you
are protecting it might only cost a few thousand dollars. Or a full-time
conversion UPS for your house? (But what protects the UPS?) Or maybe a
ferroresonant transformer? You could use it to help heat the house.
Or maybe a full-time off-grid generator? And get rid of the troublesome
phone and cable lines?
--
bud--