Planer Thicknesser Fuse Blowing Problem - Help

[The Gent]

Hello,

I have a Fox F22-568 and am having some technical problems, when pressing the on button the machine would appear to start working but then cut out after about a second before getting anywhere near to top speed. When pressing the one button afterwards absolutely nothing happened.

I tried replacing the fuse (13A) from another tool that I knew to be working fine, and the same thing happened again, the machine would start to work but then cut out after 1 second.

I put the fuse back in the known working item and this failed to work, so I isolated the fuse as being the problem. I tried this once again with the same result (3 fuses now gone).

The only question what is causing the fuse to blow, any advice on what to do next. I work for a large manufacturing company with electrical engineers that I could ask for some assistance. Any other words of wisdom would be gratefully received.

Regards,

(Planer Thicknesserless) Kevin

 

[Digit]

The fuse isn't the problem Kevin, it's the result of summat up with the machine. Has it just started doing this? Were there any problems before? Was the machine getting noisy? Has the motor been getting hot? How old is the machine?

Roy.

 

[The Gent]

This is the first time that it has done it, no noticeable deterioration in any performance, noise or heat.

The machine is about 12 months old, although I bought it second hand. I have had it for 3 months and am only a hobby user so I haven't been thrashing it so to speak.

Who would I speak to to get it sorted if summat was up with it.

Thanks,

Kevin

 

[Digit]

Till I retired Kevin I was an electrical engineer, but not on smaller motors such as this. I think you will find 9 fingers, (bob) second to none.

Roy.

 

[9fingers]

Kevin,

Is this an induction motor we are talking about or a high speed brush motor? On the latter there are normally two screw covers diametrically opposite one another to access the brushes.
An induction motor is quieter and often has a cylindrical bulge on the side somewhere which is the capacitor.

Can you post a photo of the motor perhaps?

Bob

 

[9fingers]

Looks like it is an induction motor and closely related to the axminster one.

The failure of the motor to reach synchronous speed is causing the current to be too high and blowing the fuse.
The fault is most likely to be the capacitor (if it has two, it will be the high capacitance one) or I have also seen dust in the centrifugal switch cause a similar problem but that was on a saw - a more dusty environment.
Replacement capacitors are between £10-20. Make sure that you get a similar capacitance and at least the same voltage rating.

Bob

 

[ondablade]

=D> Dr. Bob does it again. Well done...

 

[The Gent]

Thank you all for your quick help. Very much appreciated.

If it is the capacitor where about on the machine can I find it and is this something that a novice can attempt or do I need some professional help?

 

[Digit]

On your pic Kevin its that bulge on the RH side of the motor.
Capacitor failures are quite common and not out of the ordinary, in other words, not a major worry.

Roy.

 

[9fingers]

There are two capacitors on your motor

indicated by red arrows

Look for the larger electrical value - this is the most likely one to have failed.

The switch is on the far end of the motor usually behind the fan either inside or outside of the motor casing.

Bob

 

[The Gent]

My sincere thanks to Roy and Bob, thanks for putting me back on the straight and narrow.

 

[The Gent]

OK so now I have the covers off, I assume that I am looking to replace the white component.

Please forgive me as I am not familiar with the values on capacitors. Can you please let me know exactly what I should be asking Axminster (I assume that these are the best place to get these from).

Do these capacitors have polarity?

Thanks again.

 

[9fingers]

The start capacitor is the blue one - electrically bigger but physically smaller (due to the voltage difference between the two)
100mFd (microfarad) at 275 volts ac
No, they are not polarised.
I'm in the workshop at the moment but later I'll have a look around for a source.
Axminster might supply spares for their own machines but maybe not very competitively
Similarly the original manufacturers might not be the cheapest either.

What is the largest dimension that you can accomodate in the holder just to help me find one.

Bob

 

[The Gent]

Hi,

The casing is 105mm by 48mm with the curvature of the motor already considered.

The 105mm needs to fit the wire in too.

Many many thanks once again.

Kevin

 

[9fingers]

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWAX:IT

This one should be suitable. The voltage is a tad lower but I consider it acceptable for a momentary application such as this one.

There is always a chance that the fault is something else but in my experience this is the most likely solution and not too expensive if it turns out to be something else.
Let me know how you get on and if you need more help
hth

Bob

 

[The Gent]

Ordered one, lets keep the fingers crossed it is this.

Thanks (I am going to have to post a box of roses).

Kevin

 

[Digit]

Capacitors for start and or run are more or less a disposable item Kevin. If you keep the machine for a long time you will probably go through the exercise again, goes with the territory I'm afraid.
Modern motors are pretty reliable, so if there was no smell of burning, once smelt never forgotten, a US capacitor is a pretty safe bet.

Roy.

 

[9fingers]

Roy, I have just had a motor in for repair that turned out to be a duff starting capacitor that had failed in the last few months.

It was dated 1950 and surprisingly was quite a high value for those days - 70 uF on a 1hp 2 poler

Older motors I've looked at tend to have a large start winding and a small start cap as capacitors were technology/price limited.

Bob

 

[Digit]

70 is blooming high, never seen one that large, it must be pretty large physically as well isn't it? What is the insulation, it was usually paper?

Roy.

 

[9fingers]

70uF is quite modest these days. I think the one on my saw is 200 or 250uF (3hp 2 poler).
on that motor, the start winding is connected to the centre tap of the run winding which allows the capacitor to be rated at 125v ac which in turn makes 200/250uF surprisingly small.

The replacement 70uF was 50mm diam x 118 long including spades. The original was actually smaller but was one of those AC electrolytics with a limit on the number of starts per hour. This was about the only way to get that sort of capacitance in a sensible volume in 50s- 60s

The dielectric is normally polypropylene for max uF per volume. These are self extinguishing and if they do go bang, it is quite a modest phut. No fun at all!!

The replacement 70uF was 50mm diam x 118 long including spades. The original was actually smaller but was one of those AC electrolytics with a limit on the number of starts per hour. This was about the only way to get that sort of capacitance in a sensible volume in 50s- 60s

Bob