measure frequency of AC power supply

K

kippu

Skilled
Can i use a multimeter to find out the frequency of AC power supply ? or is there any cheaper ones

I stay in a township which gives backup power supply and sometimes i am not sure if its AC or generator backup which is expensive , so someone mentioned i could measure frequency and find it out , now the question is how to measure frequency
 
Some multimeters like the Meco 801 can measure frequency. Not sure how it would help though, since even a generator should maintain the frequency roughly around 50Hz. The only option I can think of is using an oscilloscope since generator power tends to be noisy, but oscilloscopes are expensive :p
 
What do you mean by "AC or generator backup"? Backup generators also produce AC, so I'm not sure what you're trying to ask. If your fans and lights are working on the backup supply, then you can be sure it's AC.
 
one of the residents did find that the frequency of the backup and the power supply is different enough to know which one is coming through
 
Simpler way is to measure voltage - line is usually a fair bit lower, but more steady than a generator.

Line frequency meters are quite readily available from industrial electrical suppliers. You can find a few on Indiamart, and maybe even your local electrical market. Seen both analog and digital models. Fairly expensive.
 
Wont the frequency be same 50hz even from backup source?
The voltage will be different though. I've measured the inverter based voltage to be around 225v whereas mains is around 235-240v.
 
apparently the main line is less than 50 hz and the generator is at 51-51.5
just a wee bit off , but good enough to measure , anyway i will get back to you guys on this ,

thanks for your help... the voltage idea is also good thanks
 
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