"cJ" wrote in message
...
I recently had a brownout due to weather related power grid issues. The
voltage on my 120 volt circuits was down to about 100-105 volts.

Any feedback regarding safe voltage range (specifically minimum) for
motors in refrigerator, freezer, sump pump and furnace blower? I do want
to protect these items while at the same time it is nice to let the
furnace run when it is 15 degrees out!

Thanks...


For the most part, electromechanical systems will not be bothered by the
type of undervoltage you describe. Things with mainly motors and switches
may loose torque but should still function at 100V. Much lower and relays
cannot hold their position and things tend to shut down.

Devices that are microelectronic may or may not be bothered by low voltage.
Most newer electronic devices with switching power supplies can withstand a
very wide range of supply voltage and be unaffected. Look at the nameplate
for each appliance or device you have to see what it is rated for.

If you do damage a major appliance, that would probably be covered by
insurance if you cared to make a claim.

Did you have anything fail after this brownout, probably not. Overvoltage
spikes due to lightning or equipment failure cause most of the damage. A
whole house surge protector installed in the breaker panel and more surge
protectors (point of use) at sensitive stuff like computers and TVs (though
these probably have that function built in) is the best you can do without
installing expensive UPS equipment.