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eletric motor

cap or not cap!

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Les Jones 130/09/2014 19:07:07
2292 forum posts
159 photos

Hi Jonathan,
A fuse or normal circuit breaker will not protect the motor. The reason for this is that motors take a much higher starting current than running current. A fuse or circuit breaker that will not blow / trip with the stating current will be rated too high to protect the motor when running. A starter has over current trips that are slow to respond so that they do not trip with the high (but short duration.) starting current. They are normally a heating element wrapped around a bimetal strip which bends when it gets hot and trips out the starter. Another method is a solenoid damped with an oil filled dashpot. Many lathes sold do not have over current protection. This is not too bad with a manual lathe as you would notice it slowing down if overloaded and you could switch it off. A no volt release is more inportant on a lathe for safety reasons. (An NVR is much cheaper than a starter with overloads.) You have not given any indication of the type of device you are driving with the motor. This information would help people give advice what kind of protection is required. Neil's example of a vacuum cleaner is one where an NVR is not that important as you would be unlikely to have your fingers in the fan assembly.

Les.

jonathon cary30/09/2014 21:05:20
44 forum posts
A flexispeed milling machine and home made hack saw so far..A smaller motor would have done but I m thinking ahead and a 1/3 hp was very little less money..
I admit I do find electicity completely baffling but itsounds best to leave Henry alone and spend more..safety is paramount..Thank you very much
martin perman30/09/2014 21:20:23
avatar
2095 forum posts
75 photos

Johnathon,

Here is a no voltage release for around £6.00 its rated for 1hp which will be more than enough for you http://www.axminster.co.uk/axminster-kjd6-switch?gclid=CjwKEAjwqamhBRDeyKKuuYztxwQSJAA1luvGCS48zzTxuIJIF4AqurmGaCM4XeY_pxj9jIUDJepsERoC36Tw_wcB

PM me if you need anymore assistance.

Martin P

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