maverick54
Established Member
Just read and article that states variable speed lathes can be switched on and off as many times an hour as is needed, but a lathe with set speeds can only be switched on and off so many times an hour. Is this correct?
Variable Speed Lathes
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Spindle
Established Member
Hi
Not something I've come across before - I've owned two variable and one fixed speed lathes and none of them came with any restriction on useage cycle.
Regards Mick
Not something I've come across before - I've owned two variable and one fixed speed lathes and none of them came with any restriction on useage cycle.
Regards Mick
RogerBoyle
Established Member
Not heard that one before
Paul Hannaby
Established Member
Where was the article and did they give any reason for the limit?
CHJ
Established Member
Presume it's some misguided generalisation relating to the heat generated in the motor during increased start up current and/or the fact that dependant upon the design of the motor the Start Capacitor may overheat.
A mechanically driven variable speed motor/pulley system is no different to a fixed pulley system in that respect.
I think you would have to be very brutal in your button pushing routine to achieve any lasting damage to either component that was of a sound design or adequate rating.
A mechanically driven variable speed motor/pulley system is no different to a fixed pulley system in that respect.
I think you would have to be very brutal in your button pushing routine to achieve any lasting damage to either component that was of a sound design or adequate rating.
RogerBoyle
Established Member
maverick54":1zemx4ht said:
The only time I have came across this was with my old Tormek Sharpner where it clearly stated that it wasn't for continous use
But it did :twisted: :twisted:
Roger
tekno.mage
Established Member
Never heard of a limit on any item as too how many times you can switch it on & off in a given period! Some cheap "hobby" rated equipment does state that it is not for continuous use (ie the motor needs a chance to cool down after a certain short period of use).
I've used several different lathes, fixed speed, variable speed electronic and variable speed mechanical and never had any problem with how often I switched any of them on & off.
It used to be thought in the early days of PCs that it was better to keep hard disks powered on than power them on and off repeatedly - which led to some offices leaving their computers on all the time (maybe only switching off the displays) - which was of course a big waste of energy and probably unnecessary as well. Some very early hard disks suffered from something called "stiction" - which happened if they were stored powered off for several months. The heads would be left on a "parking area" of the disk at power down and in storage could "stick" slightly to the disk surface and require manual assistance to get them moving again - but that was with hard disks over 30 years ago!
Some types of equipment do appear to fail more often at switch on - but that is probably because a component was on it's way out in any case, and the inrush current at power on was the final straw.
I've used several different lathes, fixed speed, variable speed electronic and variable speed mechanical and never had any problem with how often I switched any of them on & off.
It used to be thought in the early days of PCs that it was better to keep hard disks powered on than power them on and off repeatedly - which led to some offices leaving their computers on all the time (maybe only switching off the displays) - which was of course a big waste of energy and probably unnecessary as well. Some very early hard disks suffered from something called "stiction" - which happened if they were stored powered off for several months. The heads would be left on a "parking area" of the disk at power down and in storage could "stick" slightly to the disk surface and require manual assistance to get them moving again - but that was with hard disks over 30 years ago!
Some types of equipment do appear to fail more often at switch on - but that is probably because a component was on it's way out in any case, and the inrush current at power on was the final straw.
chipmunk
Established Member
Could this be related to the use of centrifugal switches in single phase motors?
In principle these will have a finite life, like switches and relay contacts, due to the contacts eventually burning away. It will be related to the number of times the unit is switched on and off. The fact that the loads are inductive will tend to lead to more arcing which will probably shorten the life of these things but it's probably in the 100's of 1000's for well designed motors.
In essence there is no such electro-mechanical component in electronic variable speed motor configurations which use 3-phase motors without the need for starter windings and so I can see where this could originate.
Jon
In principle these will have a finite life, like switches and relay contacts, due to the contacts eventually burning away. It will be related to the number of times the unit is switched on and off. The fact that the loads are inductive will tend to lead to more arcing which will probably shorten the life of these things but it's probably in the 100's of 1000's for well designed motors.
In essence there is no such electro-mechanical component in electronic variable speed motor configurations which use 3-phase motors without the need for starter windings and so I can see where this could originate.
Jon
EnErY
Established Member
Never heard of That i Got A speed genie and it gets Turned on More Times Than a Woman Of The night In kings cros s
regards
Bill :lol: :lol: :lol: :lol: :lol: :lol: :lol:
regards
Bill :lol: :lol: :lol: :lol: :lol: :lol: :lol:
Dominik Pierog
Established Member
tekno.mage":3tls2c36 said:
You can order the processor with defined (10k, 20k, 100k etc.) maximum number of cycles.
After crossing the the set value >dies ...
http://www.youtube.com/watch?v=251qoGOqpdk
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