If a fan doesn't have a capacitor it will shudder back and forth but can start with a manual hand spin

[steven100]

you learn something new everyday .....

 

The 8 watt fan I have near my desk sparked and stopped.  I pulled it to pieces and found broken wire in the center plastic shaft cause by the electric cable turning inside and eventually snapped a wire.  I rejoined the wire and glued ( my thai friend borrowed my soldering iron, it's gone. )   it back and covered/protected it in clear tube and epoxy inside. 

 

Anyway,  there is a spring mechanism at the back of the plastic shaft which assists to start the fan, as there is no capacitor I guess this is required to get the fan to turn at the start.  I'm trying to figure a way to start the fan without using the mechanism provided as it doesn't seem to work so good because the cable turns inside sometimes and eventually twists causing a break.     I will try a spring at the front ... hidden behind the covers of course,  I just need to get the right elastic or spring fixed in place so it turns under stress then spring back and away she goes. 

 

I'm no electrical guy obviously ....    Lol

 

 

 

 

[Crossy]

Yeah, a single-phase induction motor will sit and hum (it's actually going forwards and backwards 50 times a second) unless it gets a bump in one direction whereupon it will continue to run in that direction.

 

What you have appears to be a ratchet / one-way device which bounces it in the right direction. I had a clock long ago which used the same idea, when it failed the clock would randomly start running backwards.

 

You may struggle to replicate its action; I'd probably just continue to start it manually.

[flyingtlger]

"If a fan doesn't have a capacitor it will shudder back and forth but can start with a manual hand spin"

 

Sounds like a human....

[Muhendis]

I seem to remember my parents had a lovely old mantle piece clock with westminster chimes. The chimes could be disabled thank goodness.

It was an early electric clock with a spring loaded stubby little lever sticking out of a slot in the back cover. If the clock ever stopped due to loss of power etc. it had to be restarted by flicking this stubby little lever a few times. That would start the mechanism running the right direction. We always knew when the clock had stopped because the rattly grindy noise made by the gears was missing from the room.

[Jumbo1968]

I have replaced the capacitors in my Hatari floor fans, spares readily available from Hatari, only a few baht each.

[hotchilli]

4 hours ago, flyingtlger said:

"If a fan doesn't have a capacitor it will shudder back and forth but can start with a manual hand spin"

 

Sounds like a human....

My ole man said everything you have to start by hand lasts longer....

[The Theory]

I'm sure you had the same feeling Tesla had at the moment.

 

 

[Brock]

Just get a new fan, they are cheap enough..

 

[steven100]

10 hours ago, Crossy said:

when it failed the clock would randomly start running backwards.

your spot on there Crossy,  that's what was happening sometimes and the cable twisted and snapped.

I have another 16" fan here in bits but I see it has a capacitor .... Can I add this capacitor into the 8 watt fan or will that not work because it came from 16" fan/motor    ?

[steven100]

2 hours ago, Brock said:

Just get a new fan, they are cheap enough..

 

that's not the point .... I like pulling things to bits to see how they work  .     Lol

[Crossy]

9 hours ago, steven100 said:

your spot on there Crossy,  that's what was happening sometimes and the cable twisted and snapped.

I have another 16" fan here in bits but I see it has a capacitor .... Can I add this capacitor into the 8 watt fan or will that not work because it came from 16" fan/motor    ?

 

No, you cannot simply add a capacitor, it needs a second winding too ????

[bluejets]

On 7/7/2023 at 9:22 PM, steven100 said:

Anyway,  there is a spring mechanism at the back of the plastic shaft which assists to start the fan, as there is no capacitor

It's commonly known as a "synchronous motor" used mostly in washing machine timers, clocks sometimes, oven timers (older ones at least) other uses as well.

One below is from a microwave oven turntable........note that this one has a gearbox attached.

 

 

[steven100]

54 minutes ago, Crossy said:

 

No, you cannot simply add a capacitor, it needs a second winding too ????

aha .....  so it's the spring method or nothing at all.  To be honest, i really don't understand how the spring method works ....  it obviously gets power then wants to spin a guess the spring lets it shudder / turn so far then flicks it back which give it sufficient momentum to go.  It's not a very reliable system ... don't ever buy anything using this method.   haha

[sirineou]

21 hours ago, Crossy said:

Yeah, a single-phase induction motor will sit and hum (it's actually going forwards and backwards 50 times a second) unless it gets a bump in one direction whereupon it will continue to run in that direction.

If I have a fan that does that, a "bump" in the right direction is certainly in order,Perhaps also. kick  ???? Followed by a trip to my local fan emporium to get another fan (Phew , I thought I would never use the word emporium .  and I paid good money for it)????

[RocketDog]

7 hours ago, sirineou said:

Phew , I thought I would never use the word emporium .  and I paid good money for it)????

Words are cheap. It's actions that count.

????

[Crossy]

7 hours ago, sirineou said:

If I have a fan that does that, a "bump" in the right direction is certainly in order,Perhaps also. kick  ???? Followed by a trip to my local fan emporium to get another fan (Phew , I thought I would never use the word emporium .  and I paid good money for it)????

 

If it's a fan with a capacitor then a replacement cap is a cheap and easy fix ???? 

[steven100]

9 hours ago, Crossy said:

 

No, you cannot simply add a capacitor, it needs a second winding too ????

Fixed Crossy,  for now anyway .....  I took the back plastic cap off and see the spring wire inside had come out of the cut slot on the shaft, hence no shaft spring affect.  I put a hook on the spring and put back in the slot,  glued the wires back together and hey presto  !!     haha  ....   until it breaks or sparks again ... 

bad design this spring/single ph motors...  

[sirineou]

1 hour ago, RocketDog said:

Words are cheap. It's actions that count.

????

Unless your action involves words . 

[RocketDog]

15 hours ago, sirineou said:

Unless your action involves words . 

Ah. You mean a politician.????

[Muhendis]

17 hours ago, RocketDog said:

Words are cheap. It's actions that count.

????

 

16 hours ago, sirineou said:

Unless your action involves words . 

 

21 minutes ago, RocketDog said:

Ah. You mean a politician.????

The action involves a sharp shove on the fan blades in the right direction to get it started.

 

A politician would likely try to form a committee to address the legalities of such action before trying to start the fan in the wrong direction.

[Crossy]

1 hour ago, Muhendis said:

... start the fan in the wrong direction.

 

So it would suck, just like most politicians

[carlyai]

On 7/8/2023 at 2:16 PM, hotchilli said:

My ole man said everything you have to start by hand lasts longer....

I started myself by hand a lot when I was young, so I should last forever. :)