single phase cap start / run motor wiring

[Jaxo]

Hi all looking some advice on a single phase motor wiring with start and run capacitors..

I've attached an image below of the wiring diagram. It is running clockwise and the caps and links are connected as shown on left hand side diagram.. the question is , is u1 live and z2 neutral or is it the opposite way ?

https://www.dropbox.com/s/gy62xnf85vcsjaj/Screenshot_2014-08-07-17-49-01.png

 

[telectrix]

no picture.

 

[Jaxo]

Sorry, wouldn't let me upload one, have now added link to first post.

 

[telectrix]

it all depends on which way you connect the L-N supply. either way round makes no odds. it's a.c.

 

[Jaxo]

Ok, well here's the problem.. I connected live to u1 and neutral to z2, fired it up and it ran fine. Was there with it running for about 20 mins then left to go to another job.

Got a call an hour later to say it was smoking do I went back and got a look. I checked caps and connections and all seemed fine although motor was really hot and the plastic connection box had melted. I fired it back up and it ran,.. but it ran like a dog. Sounded like it was sticking more than anything else.... And no smoke.

We phoned the supplier who said live and neutral where the wrong way about, so I reversed them and turned it on and it then started smoking and popped the mcb... (Had not popped the mcb until this point)...

Just wondering if I've actually wrecked this motor or if it's a duff one... ?

 

[Silly Sausage]

It's not a 110V motor per chance?
I did that once, shoved 240V on one and wondered why it smelt funny.

 

[Jaxo]

No It's def 230 mate

 

[Pete999]

Centrifugal switch not disconnecting the start winding???

 

[telectrix]

pete's post makes sense. connecting L and N arse about face would make no difference whatsoever to the motor. only othe thing i've seen is where the thing was plugged into a long, cheap extension lead and volt drop caused it to stall and burn out.

 

[Jaxo]

Cheers guys I was starting to doubt my sanity and have been checking countless wiring diagrams online.. centrifugal switch not disconnecting does make the most sense.. Was just concerned I'd damaged it

 

[Lucien Nunes]

My suggestions in order of likelihood, assuming it's not mechanically overloaded or for wrong voltage / frequency (what's it driving?):

Cap faulty
Centrifugal switch didn't trip
Winding faulty
Caps connected wrong way

As above, nothing to do with supply polarity, makes no difference. One fault can lead to another. Mechanical overload can prevent it reaching speed, so the switch doesn't open, so the start cap fails, burning out the winding.

 

[Jaxo]

It's running an extraction fan for a spray booth. It's turning a blade approx 2 foot in diameter.

Wouldn't imagine I would be a great load turning blade.

I did suspect there was a faulty cap or one was connected incorrectly but there all correct according to the diagram.
https://www.dropbox.com/s/pl02auf5ecrhz94/IMAG1279.jpg

 

[Lucien Nunes]

If the motor and fan were supplied as a unit you wouldn't expect an overload scenario, although FWIW propeller fans can absorb a surprising amount of power.

Sounds like faulty cap or winding, send it back...