Can Brownouts Damage Motors?

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Old 06-21-20, 06:38 AM
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Can Brownouts Damage Motors?

We survived a power outage last night, followed by a brownout when power was restored. I figured the brownout could damage electronics, so I unplugged everything in that category.

Question is....can the low power damage motors too? I thinking the AC condenser motors, the furnace blower motor, frig etc... I mean the we had about 150 volts on the panel instead of 240 and 75 instead of 120. What do you think? Thanks!
 
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Old 06-21-20, 10:08 AM
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Short-brownouts shouldn't affect motors (or anything for that matter). Low-voltage can cause motors to overheat because they draw extra current to run. If it's a short-duration brownout, it's not a big deal. But if they are running for a while, or this occurs often it can damage the windings. To be honest, I don't know what a reasonable amount of time to run, but if possible, you should try not to.

More of the concern is when the power comes back on, if it's not well controlled by the power company, there can be a surge which can damage all sorts of things. Especially with trees downing power lines and such in a storm, surges can occur either as the power is lost, or it comes back on. Power companies are installing a lot more equipment these days to help prevent these surges though.
 
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Old 06-21-20, 10:09 AM
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Induction motors will definitely suffer increased heat loads when presented with low line voltage. I would say most fractional HP induction motors include a winding thermostat for protection. The very small shaded pole motors used for reefer air movement should not be affected though.
 
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Old 06-21-20, 12:59 PM
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Thanks Z and TC guy....yes another story....we destroyed 2 point of use and tripped the panel surge protectors when the power came back on. I heard a pop that almost sounded like a gun shot. Happily we lost no electronic equipment.
 
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Old 06-21-20, 01:26 PM
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.we destroyed 2 point of use
Point of use water heaters ?
 
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Old 06-21-20, 02:46 PM
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we destroyed 2 point of use and tripped the panel surge protectors when the power came back on.
I assume point of use surge protectors.
Sounds like they did exactly what they were supposed to do. Sacrifice themselves to protect your other devices.
 
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Old 06-21-20, 03:00 PM
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Ouch. You sustained a high line long enough to take out the surge suppressors.
Likely a switching transient from the POCO. They might cover the damage if you can correlate to power restoration.
 
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Old 06-22-20, 09:01 AM
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Destroyed 2 point of use plug in surge modules, Strangely these were also plugged into surge protector wall outlets and these SPD outlets survived OK however.
 
 

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