Improper Use of Electric Motor.

For those who do not like Bing, here is the original on youtube, which is only marginally more honest about nicking your data.

But in short do not spin grinding disks at higher than rated RPM, and do not try to jury rig a grinder using random bits lying around. As if we would put a grinding disk in the electric drill..

Can’t see the first link as my browser has blocked it as unsafe. I do have to question the point of this, as it has no relevance to BS7671. I suppose you could say it has an electric motor, but that is a bit tenuous for posting here. 

Regards,

Alan. 

Alan Capon: 
 

Can’t see the first link as my browser has blocked it as unsafe. I do have to question the point of this, as it has no relevance to BS7671. I suppose you could say it has an electric motor, but that is a bit tenuous for posting here. 

Regards,

Alan. 

There are many students and other learners that will benefit from the information Alan. It is interesting to research the speed of universal series motors which may be involved. The type used in vacuum cleaners etc. With no braking effect, such as from a fan or other load, they can over speed to destruction.

All associated knowledge of wiring and the regulations is beneficial.

Oh, and with due deference to others, I did not post a Tesco propaganda video about reducing dairy cattle emissions by adding a supplement to the cows' food. I though that was a bridge too far. I am sure that you can find it though via a non Bing route if you feel the need.

Z.

I experienced this issue myself. On a ship I was serving on we had a hand-held grinder that the 4th Engineer used inside the main engine cylinder during maintenance. Unknown to us, the spare grinding wheels we had been supplied with in Japan were rated for a lower speed - with the details all in Japanese we couldn't read the warnings - and the wheel shattered inside the cylinder where the 4th Engineer, incredibly luckily, only suffered broken legs and lacerations with no injury to his upper body or head.

In hindsight we were able to decipher the speed ratings and scrapped all the wheels we had been supplied, while the 4th Engineer was airlifted to an Italian hospital and made a full recovery. However, since then I have always been slightly nervous of grinding wheels and check the speed rating of any that look new.