Howdy Folks,

I am the semi-proud owner of an old beat up Fiorenzato 71mm conical grinder. The thing has a very loud startup sound for about four seconds. I have read Jim's review, subsequent threads, etc. and the typical problem is the 500 watt motor. Mine has 700W.

I need new capacitors. Either they have gone bad, or they were wrong to begin with. I tend to think the latter. Does anyone with electrical know-how know what capacitor I need? Any chance I can get small box-style ones?

The capacitor on the left says:

60 (presumably uF +/- 5%)
400V ~ .....
450V ~
25/85/21


The larger one on the right says:

Xeono B03000X800C3g
0-80 uF +/-b MK SH
130/450VAC
50/60 Hz ..... 70
Motore .....30
20/40/05


The motor is:
V.A.C. of 115. 50/60Hz 700W

John,

Are you experiencing stalling or just a loud startup sound?

Just a loud startup noise for 3-4 seconds.

New caps would be a good idea anyway if it is an old grinder, they do age.

Just read that there is a general ruke for cap size but that it depends on the type of motor (single phase etc), I reckon the 80 uF is ok for the normal 500W motor but from what Inread you'll need a bit more for a 700 W engine. it might just be that they added the second cap of 60 uF when the motor was upgraded
The second cap could also be for when the motor is running, and in those cases is a lot smaller in capacitance than the starter cap. google should be able to guide you as I am afraid you'll need the motor characteristics, but the original wiring will help (if they added the second cap on installing a heavier motor they will be connected in parallel)

As a general rule you"ll need to look for starter caps, as they are quite specific types of caps.

125VAC or above is fine, a bit more than the mains voltage always is nice as spikes do occurr but their size will increase with the rated voltage.

You could contact an electronics supplier, they'll know what you need if you have the wiring diagram an specs available. Just looked at a webshop and it may be worthwile to use a couple of smaller caps from a price persepctive, all depends at availability and price where you live...
(100uF is aprox 200€ here as those only come in a 630Vac rating while a 60 uF 250vac is only 20€ or thereabouts)
120uf or thereabouts for the starter cap and in case you need a running cap some 60uF should be ok but please do check.

Last time I needed a starter cap I ended up at a local wholesale supplier for HVAC repair men. Really good prices and stock. They seem to be getting both harder to come by and more expensive as things get repaired less and we move to more efficient power sources.

Ira

They are more expensive depending on the choice of dielectricum, MKP is pricey but will last long too.

In this case I would check out the wiring and type of motor as the cap size and type is much more critical when a motor has to deliver torque and the cap is not just a startup help.

Take your old capacitors & your motor info into any local Graingers branch & they should be able to set you up.
http://www.grainger.com/

Thanks for the advice guys. I think I'll take it into an electronics supply store and see what they have to say. I only know what I've printed, and the motor has no plate on it saying anything.

The larger one is plugged into the smaller one which goes to the motor, etc. I'm not sure why the larger one says 0-80 uf and not a specific number like 80uF. I only know enough to know that you have to get the exact uF rating or it will make noise. Is this common for startup capacitors?

The size and type of capacitor is critical to motor performance and service life. You need an actual wiring diagram or the ability to differentiate between a staring capacitor and a running capacitor, they are not the same and are not rated the same way. If you really want to do this right then you need a electric motor repair shop where the person will be able to tell what is needed.

The usual consequence of getting this wrong is a failed motor.

The 0-80 appears to be a starting cap and the 60 a running cap. Either one or both could be defective.

Not real sure I am buying the 0-80 is all the marking that should be there either.

It's typical that they cover a range but usually it's not that wide.
http://www.grainger.com/product/DAYTON- ... 1?$smthumb$