Myford 254 Electrical problem

[Old SchoolParticipant @oldschool]

[Old SchoolParticipant @oldschool]

I have had this lathe for a few months and in general use everything works fine. This weekend I have been turning down steel bar working the lathe quite hard, fairly fast with a .060 cut and the turnings coming off blue. After a while when stopping to measure it will not restart. The motor is only warm to the touch if you can hold your hand on no problem.

If switch it off press the red reset button inside the box on top it will sometimes start again. Or it will start after lunch. The problem must be heat related but what is the problem any ideas gratefully received.

Olly

[Mike PooleParticipant @mikepoole82104]

Hi Olly,

I would check that the overload unit is set to the full load current of the motor and if you have the equipment and knowledge to use it, check the actual current the motor is pulling under the load you are applying.

More details of your lathes motor control would be helpful i.e. is it single or three phase, does it have an inverter?

Mike

[Ian HewsonParticipant @ianhewson99641]

Hi

Sounds like you have answered your own problem, my 254 would not like those cuts in cold weather with cold gear oil taking power .

Ian

[MadMikeParticipant @madmike]

If your 254 is single phase then it is probably the starting capacitor that is at fault. It is worth getting somebody to check and fit a new one. They are available from RS and do not cost more than about £12 as I recall.

[Old SchoolParticipant @oldschool]

Thanks for the responses so far

Michael its a single phase machine the electrian at work has offered the necessary kit to carryout the testing.

Ian I have not worked it any harder than I did my Raglan Little john a similar sized machine not sure how big the motor was on that.

MadMike hope its that an easy fix will talk to the electrician.

Olly

[Keith LongParticipant @keithlong89920]

Olly

Don't forget to check any switchgear / contactors fitted as well. They can give problems, it might not be the motor.

If your motor is capacitor start it will have centrifugal switch fitted in one end, to switch the capacitor in and out of circuit, dirty contacts or wear in that mechanism can give rise to starting problems as well.

Keith

[speelwerkParticipant @speelwerk]

Had similar problems with my S7, checked everything, finally it turned out it was the NVR-switch, the contacts were totally gone, only visible when you took apart. An original new one from Myford’s German supplier was extremely expensive, it now has a left over one of unknown make which functions fine. Niko.

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