Sealey Bench Grinder Auto braking not working.

[rizla01]

My lovely old SEALEY 150mm Model RM53 Bench grinder has developed a problem insomuch as it wont slow down as it should.

Thinking prob centrifugal in reveres braking, I phoned Sealey for the parts and apparently its built into the motor.

Hmm? Is this the DC voltage braking I learned once about I wonder (rectifier??) or something else.

Has anyone had success with remedying this issue of do I have to suffer a free spinning grindstone from hereon in?

Thanks for looking.

 

[bernardgreen]

The usual method of breaking is to short out the motor with a low impednace resistor when power is removed. The rotating motor then acts like a generator converting the energy of rotation into electrical energy which is absorbed by the resistor.

The exact way the resistor is connected to the motor when power is removed varies from machine to machine. In some machines the resistor is switched in by the ON_OFF switch being in the OFF position. Some machines use a relay and some use an electronic circuit. Other methods are available.

 

[rizla01]

The usual method of breaking is to short out the motor with a low impednace resistor when power is removed. The rotating motor then acts like a generator converting the energy of rotation into electrical energy which is absorbed by the resistor.

The exact way the resistor is connected to the motor when power is removed varies from machine to machine. In some machines the resistor is switched in by the ON_OFF switch being in the OFF position. Some machines use a relay and some use an electronic circuit. Other methods are available.

Thanks Bernard.

The failure to brake happened quite slowly - not all of a sudden.
It worsened over time so would that happen if it were a resistor doing the braking?
If that isn't the culprit how easy would it be to wire in a resistor for that purpose?

 

[bernardgreen]

The failure to brake happened quite slowly - not all of a sudden.

Which means it very un-likely to be a failed resistor. I would not be able to give advice without knowiing exactly how the braking action is activated. There is also the safety aspects if it is modified in any way and an accident results.

 

[rizla01]

Which means it very un-likely to be a failed resistor. I would not be able to give advice without knowiing exactly how the braking action is activated. There is also the safety aspects if it is modified in any way and an accident results.

I understand.

Might consider a strip and peek to see what that tells me.

Thanks for tat useful info, anyhow.