Fault finding single phase motors

[daiplayer]

Ok got called in regards to somebody's electrica gate not working.

Power supply all seems good.

After removing the motor i attempted to test the windings. ( i really havent done much with motors)

the motor is single phase. Has a N , 2 feeds/supplys/windings. ? is this one :- Electric Gates Accessories, Replacement Liftmaster Sub300 Motor - Gateauto

Ok firstly i tested the other working motor. :

- one winding to N - 34 ohm
- other winding ( reverse winding ?) -N 34 ohms.

On faulty motor :-

- One winding -N 145 ohm
- other winding - N - infinite/open circuit

Am i correct in saying the this motors windings are F****** ?

 

[MarkieSparkie]

Yes, it seems you have answered your own question.

 

[grantr37]

send it for rewinding if it is of a suitable construction......

- - - Updated - - -

will be places on the internet...

 

[Knobhead]

Not worth rewinding. Just replace it.

 

[oldtimer]

I worked with a company that got such a good discount it was only big motors that got rewound as it was more cost effective to buy a new motor as the down time was minimal

 

[Knobhead]

Anything below 20HP just went in the skip. As you say, time is a big factor.

 

[oldtimer]

Anything below 20HP just went in the skip. As you say, time is a big factor.

Agreed I had a motor with noisy bearings but it was the main kitchen extract so we bought a new motor and the down time was 1 hour if we had taken it out for repair it would have been most of the day but as a wee project we refurbished the old motor

 

[daiplayer]

Thanks all.
Out of interest and a need to learn ....
Anybody know what sort of motor this is ?
It has a 10uf capacitor connected at its power supply . Is this just for power factor correction?
How deos this motor reverse? Is it a complete separate winding then?

 

[oldtimer]

If its a small motor it could be a capacitor assisted start

 

[telectrix]

reversing is usually achieved by reversing the start winding wrt the run winding.

 

[daiplayer]

Split phase induction motor ?

 

[Knobhead]

Permanent capacitor?
Capacitor start?

Can't tell with out more info.

BTW had you said this at the start my answer would have been different

 

[daiplayer]

yes permanent capacitor , have been trying to find wiring instructions as i cant remember where the capacitor was connected . was def at the power source though.

 

[micknew]

Capacitor go's in series with the start winding.

 

[Engineer54]

Motorised automatic gates are notorious for breakdowns, and even when repaired, and left working perfectly will have a tendency to fail again quickly, making you look as if you don't know what your doing to the client!!.... In future avoid them like the plague!! lol!!

 

[daiplayer]

Learning that one pretty quick , lol

 

[Des 56]

They may also be bad news to work on regards their design
There was a toddler killed here in Maesteg,it was caused by bad design and there are quite a lot about of a similar standard apparently

When working on these contraptions I suppose that the function of the gatestops and their support structures should be confirmed as safe before doing repairs,just in case of potential problems iwith their design and your own responsibilities

 

[daiplayer]

funny enough i had a look at how the other gate was operating , although they had safety photocells , the closing force on each gate was set way up !! only for small iron gates too. so turned it down by more than half.

 

[electricgates]

Liftmaster motors are junk bin them. Get something more professional.