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Generac generator output

kimden5

Sep 28, 2017
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I have a 16 KW generac whole house generator and during our recent "Hurricane Irma", it ran for about three days. During this time all of our electric powered digital clocks (stove, microwave, coffee maker etc.) lost considerable amounts of time every day ( 1 to 2 hours). I have talked to Generac (customer service) and can get no solid answers. I'm wondering if the cycles were off a little (less than 60), but a local generator tech. told me that if it varies more than 1 or 2 the unit would automatically shut down. The voltage was running between 118 & 124. I also noticed that our A/C unit sounded a little "off" from normal and one of our ceiling fans was making an unusual sound. Everything is back to normal now that we are back on commercial power. Anyone have any thoughts ? Thanx
 

Minder

Apr 24, 2015
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Generally modern appliances do not use the mains frequency anymore for time, it is done using a 32Khz Xtal.
You could do some test as to its frequency if you have a 'scope, and also look at the wave form.
1 to 2 hrs/day is ALOT!
M.
 

duke37

Jan 9, 2011
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I have a meter which will measure voltage, current and power also frequency. This was obtained from a cheap supermarket, about £8.
Testing a friend's small generator showed a frequency of 51Hz unloaded and 49Hz fully loaded.

Running with a low frequency can give problems with inductive loads. The generator would be running about 7% low.
 

Kiwi

Jan 28, 2013
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My guess would be that the generator is running at about 56Hz, instead of 60Hz.
Get it tested while under load to confirm.

"....if it varies more than 1 or 2 the unit would automatically shut down."
Generators are not set this fine for under frequency.
 

Bluejets

Oct 5, 2014
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Sounds a bit like it might have been running close to or a tad over maximum load.

"stove, coffee maker, air conditioner" etc etc
 

kellys_eye

Jun 25, 2010
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You're missing @Minder comment - that modern appliances with digital timers/displays don't USE the mains frequency to derive their timing......
 

duke37

Jan 9, 2011
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You're missing @Minder comment - that modern appliances with digital timers/displays don't USE the mains frequency to derive their timing......
But several clocks all did the same thing so likely to be synchronous clocks.
 

BobK

Jan 5, 2010
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Who said they were modern clocks?

Bob
 
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