Starter capacitor help needed!

[Benn]

Afternoon all

anybody with any knowledge could help me out ,im currently buggerd,

im stuck with trying to find a new starter capacitor for a motor

The motor is 230v a.c,50hz 1hp,
3000-9000 rpm
Input is 3100w
Output is 2250w

i changed the starter capacitor for the one in photo,
Now after the motor running for a while it trips the main rcd.
im currently knackered without the machine so any help mich appreciated.

cheers

 

[f0ster]

was this cap the same size as the one that came out? 60uf appears to be a bit large for such a small motor, I have a motor that uses a cap of this size but it also has a small one also, connected to a different set of winding's (6uf) but this an exception, normally a start cap would be in the region of 10uf and usually only one,

 

[Benn]

i cannot find the cap that came out of the machine And somebody else changed it for this one,It physically bigger as i struggled to get it back into its housing.
There is only one cap that i can see ,
The machine starts and runs fine but after the motor warms up its trips the main rcd,

the cap is the only thing thats been changed a couple months ago,As the last cap blew up,

Could it may be the motor getting faulty as when it gets hot and not the cap?
We Have already changed the main rcd as thought this may beFaulty.

 

[Tim G]

i cannot find the cap that came out of the machine And somebody else changed it for this one,It physically bigger as i struggled to get it back into its housing.
There is only one cap that i can see ,
The machine starts and runs fine but after the motor warms up its trips the main rcd,

the cap is the only thing thats been changed a couple months ago,As the last cap blew up,

Could it may be the motor getting faulty as when it gets hot and not the cap?
We Have already changed the main rcd as thought this may beFaulty.

Had a motor do similar recently, the insulation was breaking down in the windings causing it to short when warm (or so I was told).

 

[Benn]

Had a motor do similar recently, the insulation was breaking down in the windings causing it to short when warm (or so I was told).

did yours trip the main rcd too?
I cant understand why its not blowing the plug fuse or the sockets rcd.

 

[Tim G]

did yours trip the main rcd too?
I cant understand why its not blowing the plug fuse or the sockets rcd.

Yes. It was particularly fun because its the motor in our cream separator (when we use it, it's while we are milking as the milk needs to be warm), so half way through milking the lights went out, radio went silent, pump shut off, clusters dropped to the floor, you get the picture!

 

[Benn]

I know the feeling,
Ah sound like The motors on way out the ,
Cheers

 

[Tim G]

I know the feeling,
Ah sound like The motors on way out the ,
Cheers

That size motor wouldn't be too expensive would it? Probably not worth Re winding.

 

[Benn]

Yeah ,think There only £100 ish new,
Will give it a try,
Cheers for the help.

 

[Jimmyblue]

Hi, yes I would suggest that it is your motor’s Insulation that is breaking down when it warms up. An incorrect capacitor would not trip an RCD especially this one as it looks to have an insulated body. I have known a dodgy Direct On Line starter cause an earth trip. It was caused not by an earth fault but a bad contact on the live side. This gave an imbalance of current and tripped the RCD. Hope that makes sense. Try borrowing an insulation tester and testing to earth when warm perhaps.

 

[Tim G]

Yeah ,think There only £100 ish new,
Will give it a try,
Cheers for the help.

Not worth buggering around with the old one.
Our separator motor was 110v dc run through a transformer which had a variable output to adjust the speed of the motor for different cream thicknesses. That type of motor is no longer available, I tried to get it rewound but no luck there either so I had to get a new motor which is not much bigger than a bean can plus a new speed controller. Bill was just shy of £2k.......

 

[Benn]

Hi, yes I would suggest that it is your motor’s Insulation that is breaking down when it warms up. An incorrect capacitor would not trip an RCD especially this one as it looks to have an insulated body. I have known a dodgy Direct On Line starter cause an earth trip. It was caused not by an earth fault but a bad contact on the live side. This gave an imbalance of current and tripped the RCD. Hope that makes sense. Try borrowing an insulation tester and testing to earth when warm perhaps.

cheers for help ,
i will get new motor ordered tomorrow and see if it solves it ,

 

[Benn]

Not worth buggering around with the old one.
Our separator motor was 110v dc run through a transformer which had a variable output to adjust the speed of the motor for different cream thicknesses. That type of motor is no longer available, I tried to get it rewound but no luck there either so I had to get a new motor which is not much bigger than a bean can plus a new speed controller. Bill was just shy of £2k.......

2k oh bugger ,That would nearly get me a Whole Good used Machine.

 

[Tim G]

2k oh bugger ,That would nearly get me a Whole Good used Machine.

I'm trying not to dwell on it too much, I took the view that a new separator was going to be over £7,000 and we had, thankfully, been given this one.
Only 1,000 pots of cream to sell to make it back..........

 

[sjt01]

2k oh bugger ,That would nearly get me a Whole Good used Machine.

These guys are good for motors at sensible prices, also for inverters for speed control

Inverter Drive Supermarket: Buy VSDs, Electric Motors for Speed Control

Low prices on large stock of Variable Speed Drives, AC and DC Electric Motors, Gearboxes, Soft Starters, DOL Starters, Control Gear and more.

inverterdrive.com

 

[7740 man]

Been there. Start Capacitor same as that on my compressor. Replaced them, then the starter switch & shortly after the motor....

 

[sjt01]

These guys are good for motors at sensible prices, also for inverters for speed control

Inverter Drive Supermarket: Buy VSDs, Electric Motors for Speed Control

Low prices on large stock of Variable Speed Drives, AC and DC Electric Motors, Gearboxes, Soft Starters, DOL Starters, Control Gear and more.

inverterdrive.com

Also note that most 400 volt motors can be reconnected in the terminal box to run at 230 v so you can use a 230 volt single phase inverter for speed control.

 

[Benn]

Sooo.....The saga continues

I cannot find the correct motor size with the Correct shaft diameter,

i bought the motor 0.75KW (1.0HP) SINGLE PHASE MOTOR 2 POLE (3000RPM) 80 FRAME
All fits but the shaft is 1mm to small,so theres play on where it sits on the pulley,

any body know if if you can get some sort collar or shims to add to increase the diameter,
i would weld the thing onto the pulley wheel bought its alloy

its needs go from 19mm to 20mm.
Anybody know how to get round it Id appreciate it,other wise i have to scrap the whole machine as i cannot for life of me find a 20mm diameter shaft,in correct motor size.

 

[AftonShepherd]

If all else failed could you find a new pulley wheel to do the job?

 

[sjt01]

Sooo.....The saga continues

I cannot find the correct motor size with the Correct shaft diameter,

i bought the motor 0.75KW (1.0HP) SINGLE PHASE MOTOR 2 POLE (3000RPM) 80 FRAME
All fits but the shaft is 1mm to small,so theres play on where it sits on the pulley,

any body know if if you can get some sort collar or shims to add to increase the diameter,
i would weld the thing onto the pulley wheel bought its alloy

its needs go from 19mm to 20mm.
Anybody know how to get round it Id appreciate it,other wise i have to scrap the whole machine as i cannot for life of me find a 20mm diameter shaft,in correct motor size.

Get the correct pulley from here

V Belt Pulleys: SPA, SPB, SPC, SPZ and J Section Vee Belt Pulleys

simplybearings.co.uk

with a taper lock centre, then select the correct taper lock for your shaft to fit the pulley

Tapered Locking Bushes: Tapered Locking Bushes in Various Sizes

simplybearings.co.uk