Myford ML8 Electrics

[The Shark]

Hi guys,
I have been using the ML8 virtually non-stop for a couple of hours today.
All of a sudden, the motor stopped going round, and there was a series of clicks from the box where you switch on. It had died . The motor was very hot to the touch.
I left it for an hour, then tried again and it worked.

My question to you learned gentlemen and ladies is: is it as simple as the motor got hot and there is some sort of thermal cut-out (hopefully), or is the motor on the way out?

Thanks in advance for any replies

Malc

 

[Jenx]

Sounds like 'Both' Malc ...
I'm not familiar with the machine, and more importantly the motor concerned with it .. but it sounds like its starting to 'object'.

Some have thermistor type set-ups, where they will cut out when they start to over-load,

Some have internal centrifugal switches...

theses 'devices' are designed to protect the motor to a certain degree, but something is indeed 'amiss' and warrants a bit of attention.

Take it to your local rewinders to have a look, or alternatively, get hold of a replacement motor with suitable performance criteria, shaft size & diameter, mounting flange etc and replace it ( often the cheapest option ).

HTH 8) 8)


( Just to quantify.. I'm sure you will have done this already, but - nothing 'else' in the drivetrain or mounted-item is causing excessive load to be put on the motor is it ? .... I'm sure you'll have checked this .. but it's more to save someone posting to say 'don't assume its the motor' when it could be something else :wink: ...... )

 

[Turn It In]

Hi Malc,
The control box where you switch the motor on I guess will have a stop and start button and they work in conjunction with contacts on the contactor below them. As well as the contactor there will be and additional piece called a thermal overload. These have a dial on them marked of in amps which is the full load current drawn by the motor and this figure should be marked on the legend plate on the motor and what ever the motor is rated at the thermal overload should be set the same to protect the motor. It may be that as your lathe is an ML8 it may not be driven by a motor of sufficient horse power and I would suggest that you should have at least 1/2hp or better 3/4hp. Also the motor may not be continuously rated and if it is getting very hot after 2 hours service it may be that thatis the case.
So those points should be checked but do make sure that the trip current is not set higher than the rating on the motor or it may not protect the motor and a burn up may ensue!!!!
The cetrifugal switch in the motor is there to connect the start winding when you first apply power to get the motor and its load spinning until it is up to speed when the centifugal switch is opened and the start winding is disconnected. If this switch holds in the start winding will burn out.
The motor direction is changed round by swapping round the connections
to the start winding so that it is rotated in the opposite direction at start up should that be required.
Well I hope that has given you a few pointers as to what to look for but always disconnect the power if you are going to check anything out and if you are not happy with electricity air on the cautious side and leave it to someone experienced.
Regards,
Ian

 

[The Shark]

Hi Jenx and Ian,
Thanks very much for your comprehensive replies.
I had been turning pens, so there was no excessive load on the drivetrain, which seems ok.
I'll try and find someone suitably qualified to check the motor out.

Thanks once again,

Malc