humming noise coming from my delta unisaw when the power is off

An energized capacitor? For kicks, unplug the machine and flip the on switch. That should (in my shaky theory) discahrge the capacitor.See if the hum stops. WOn’t fix anything, but it might narrow down the possibilities. Might signal the beginning of the end for the capacitor. Good news is that a new one can be had for a few bucks.

Oh, and if the hum stops upon unplugging the saw, the switch will be the number one suspect.

Unisaws never break down. Must be the user. ;)

-- jay, www.allaboutastro.com

You may also find a relay that is energized by design which is buzzing slightly. If that’s the case, no problem.

-- Failure does not stop me, it makes me try harder..... because I'm crazy.

Tedstor, never seen a cap make noise unless it’s blowing up or discharging and I don’t think that saw would hold a charge unless the diode is bad in which case there still would be no noise.

-- Failure does not stop me, it makes me try harder..... because I'm crazy.

My Dad bought his Unisaw new in the 80’s, and the electrical box (not the on/off switch) has hummed from day one. I always thought it was just the nature of the magnetic switch. He always unplugs it when not in use. Is there really a malfunction here?

Sometimes I get complaints about my humming in the shop, but I find it relaxing so I do it anyway! ;-)

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

The magnetic switch on these saws has a 24V transformer. It drives the main contactor that supplies power to the motor. The humming you hear is most likely the core laminations vibrating at 60 Hz.

-- "Find out what you cannot do and then go do it!"

”Hello my Dear,
How are you today?
My name is Miss Zabrina, i am a young girl, i was impressed when i saw your profile and become interested to know more about you, Please If you are interested in knowing more about me, i will like you to reply me: – misszabrina24@yahoo.com
Miss Zabrina”

Miss Zabrina – Would like to hear some of my humming?

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

and I just got a pm from her
I will thank her with a spamflag :-))

DoubleE nailed it. Xformer 60hz buzz

+1 for eengineer. the unisaw i just sold, which had a magnetic starter, hummed the first, and every time, i plugged it in. a little unnerving the first time it happens. on the plus side, if there’s a loss of power during operation, i’ll bet the saw won’t restart upon power restoration until the “start” button is pushed. nice little safety feature.

-- there's a solution to every problem.......you just have to be willing to find it.

My thoughts are that it’s actually an explosive device with a timer. Therefore you should ship it to me immediately for deactivation…....disclaimer…..I know nothing about electricity.

-- Don't rollerskate in a buffalo herd