Anyone with an electronics background know what this is in my extraction fan?

Picture first, then some information.



So a long time ago I picked up a job lot of silent box fans second hand because the ones I've been buying are no longer available (chinese import)
Took a chance on these because they were less than one new one for 4

As soon as i got them I tested them out.
1 is super quiet.. but not so strong.
1 I rather loud, suspect bearings. Powerful
2 are a balance of quiet enough and powerful enough.

So I stripped down the loud one to see if could fix the issue.
Nearly a year later and I've reassembled it to remind myself how Loud or not it was.

Something that I always found odd is the super quiet one clearly runs less air even though all 4 are identical fans.

This black thing I do not know the purpose of.
But i assume its why one is moving less air.

This is the only wiring.
There is no speed controller or switch.
Simply a plug and this wiring and this black block.
The blocks are identical in all fans.

Anybody any clue as to what it is and why one fan would be slower running?

Cheers

PS figured I have a better chance of someone with electronics background in the LED section.. despite this not being LED related

So having googled the 1.5uF written on the block , it brought up these exact things on ebay. £3.50 for 3.

It's a capacitor.. a case of posting a thread before looking I guess.

So now I'm thinking maybe I should remove the capacitor from the noisy but full speed fan and put it in the quiet but slow fan.
Because apparently a dodgy capacitor can cause a fan to run slower.

I'm confident the noisy element is the bearing , as it's noisy when hand spun.

Yep . Swapped the capacitor and now the noisy fan is slow and the quiet one is full speed.

Brucey bonus

Nothing like a man that sorts himself out!

Edit: um yeah, i see... the unintended pun came back to bite me before i even realized what i wrote...

Im gonna say Chinese listening device

Yep it's a line side capacitor - likely a "starter cap" that holds a charge to give the armature a little more "oomph" to roll over.
When they are out of tolerance they will cause various things like lower start torque (it's intended purpose - our old furnace needed one and the main motor before the $9000 BOHICA new one) and speed, hum and temperature are other thing that can be affected.
Wish I would have seen this earlier but you got it sorted and the exact same part is a lot easier to change, though I am usually leary of old stock being out of tolerance.

coreywebster said:

Picture first, then some information.

View attachment 5339275View attachment 5339276

So a long time ago I picked up a job lot of silent box fans second hand because the ones I've been buying are no longer available (chinese import)
Took a chance on these because they were less than one new one for 4

As soon as i got them I tested them out.
1 is super quiet.. but not so strong.
1 I rather loud, suspect bearings. Powerful
2 are a balance of quiet enough and powerful enough.

So I stripped down the loud one to see if could fix the issue.
Nearly a year later and I've reassembled it to remind myself how Loud or not it was.

Something that I always found odd is the super quiet one clearly runs less air even though all 4 are identical fans.

This black thing I do not know the purpose of.
But i assume its why one is moving less air.

This is the only wiring.
There is no speed controller or switch.
Simply a plug and this wiring and this black block.
The blocks are identical in all fans.

Anybody any clue as to what it is and why one fan would be slower running?

Cheers

PS figured I have a better chance of someone with electronics background in the LED section.. despite this not being LED related

Click to expand...

Capacitor, a replacement may look different