Clarke bobbin sander COBS01

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I have just bought a second hand Clarkes bobbin sander COBS01 at an online auction. However it doesnt spin or oscilate. I'm really not sure what's wrong with it and having rung several repair people no one will help me. There is power to it I believe as it makes a quiet whirring noise but so not sure if it's the motor or switch. Belt are all ok
Anyone have any helpful suggestions as to what the issue may be and how to fix it.
Thanks
Charlotte :)
 
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Need more details, (and photo's if possible), such as voltage, speed, does it have capacitors or a centrifugal switch if it's single phase, (230v but, depending on age may state 240v).
Is it definitely a whirring noise or could it be a humming noise. Is the drive motor visible to see if it is actually turning, and if so, what kind of speed does it appear to be running at.
What type of belts are they, (plain V, grooved, toothed, flat, circular etc). Do they feel tight enough that you can turn them sideways and NOT be able to turn them to a 90 degree angle. What is the gap between the belt sides and what does it decrease to when you squeeze them together?
With the power off can you turn the bobbin? If the answer is no then remove a drive belt and try again. If you still can't turn it is there a brake? If so can you release the brake manually? i.e. it is not an electrical brake. If it is an electrical brake there should also be a means of releasing it in the event of a power failure. This can take the form of a bar that you insert into a hole at the side of the brake or you may need to adjust a lock screw.
Was it auctioned as working, just out of interest.
 
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230v its a COBS-01
- humming is a better description. I thought it might the switch or motor. I'll have to check the belts and revert. No manual brake. Can turn the bobbin spindle.
Have sent the manual as I dont really know what Im doing. Ive asked the aucton house if there is any redress.
Thanks
C:)
 

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If it is humming then the most likely problem is a 'Start' capacitor. Don't know if you know much about motors, or electrics, but you need to look for a small cylinder with some wires coming from it. On the side of the cylinder, (capacitor), it should have a label or be printed on the surface, words like; 400v, 250uf, (That is a sample number. It is the uf you are looking for).
So, if you find this you can then source a new one from an electrical wholesaler or even Amazon/Ebay. Note down the details and measure the diameter and length as they come in various sizes, even when the uf is the same. It may be contained in a plastic case or simply strapped to the side of the motor or even inside the terminal box of the motor. When you get the new one simply disconnect one wire at a time from the old one and attach them to the new one.
Forget that. Just seen the exploded diagram and it hasn't got one. Ok, first thing to check are the carbon brushes, (item 34 slightly right of lower centre at the bottom of the armature). Check them for length and that they move freely in the brush box. Check the spring is pushing them right up to the commutator, (the copper bars with slots between them). You may need to get a new set of them (2). because they may not quite be touching the surface.
Worst case scenario is you have shorted turns of copper wire on the armature, (the spinning part), or in the field coils. You can get replacements but if you are not electrically + mechanically minded/adept it can be difficult to replace them correctly.
 
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Hi
Thank you so much for all your help - I'll try your suggestions and let you know how I get on! :)
 
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Hi
Ive checked the brushes and they look ok to me (although I'm no expert!) . I took the switch off and have relaised that the humming noise is comring from the switch, so IVe ordered a new switch and will give that a whirl.
Thanks for your help again - fingers crossed
C
 
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