I've never seen a thermal cut-out in this situation, but the only centrifugal switches I've seen have been dry. I can't think of any other reason for the seemingly fixed time delay in resetting. If a mechanical issue with gunk or grease I would expect the delay to reduce as the motor warmed up, if thermal switch for the delay to increase.
Can you take a photo of the plate indicating manufacturer and model etc?
Should these things have oil & grease on them? If not, what (or nothing)?
On 27/09/2021 21:53, Fredxx wrote:> I can't think of any other reason for the seemingly fixed> time delay in resetting.
It's not fixed! As before, it varies from a couple of seconds to nearly
Yes, as in my reply to Mr Rumm:
The motor's plate is here:
They should be clean and dry... depending on the motor design if you can get to it (might need to take the cowl and the fan off), you should be able to get at the switch and check it moves properly, and look at the contacts. They should be closed when it's at rest. If you push the weighted bits outwards, the contact should open.
Nice expo here:
Wrong. Totally wrong. All motors have a rotor winding, even if it's just a squirrel cage.
the only motors that have only one set of windings, are motors that feature *permanent magnets*
If the blind lead the blind, they both shall fall into the ditch
A squirrel cage - the most common arrangement on a an AC motor's rotor - isn't a wound coil. The coils in the stator are wound coils.
I served an apprenticeship in that trade. Never did it again after the age of 22, though. There's more to life than a workbench eight hours a day.
It's not totally wrong. I wouldn't call a squirrel cage a rotor winding.
Not all motors even have copper in the rotor. There are a number of motors that use iron rotors, usually in conjunction with magnets.
Wrong again. Look up hysteresis motors and reluctance motors.
Yes, you seem seem to be utterly unhelpful and seeming pounce on every opportunity to try an make a point. As usual your efforts backfire and make you look a plonker.
Sorry I don't feel much wiser the 'net is pretty quiet on all the motor numbers.
Well that is semantics, and no, a squirrel cage motor is fairly rare. Most AC motors usre unversal motors with brushes
Most induction motors have two sets of windings, and one set of coils fed partially by a capacitor.
'Kinell. google wanted me to give them my credit card detais or send photo ID to prove I'm over 18, so I adjusted their changed settings back. Looks like they will change again "every so often".
I'll have a look at that switch directly.
Most low revving motors used in tools and the like are induction motors. Even lawnmowers are marketed on having an induction motor.
Now some fool back-pedalling after claiming, "All motors have a rotor winding" is excusing themselves on semantics.
Most induction motors are either 3 phase or shaded pole. Even where there is a second winding sometimes that is occasionally designed to be lossy so it doesn't have the reactive current in phase with the main winding.
But clearly not the type of motor being discussed here...
When did that ever matter to TNP? ;-)
Tim
The squirrel cage itself is a proto-winding; heavy currents flow through the elements of the cage, otherwise it just wouldn't work.
The copper in a squirrel cage or deep bar rotor would normally be called a conductor and not a winding. Any conductor would do, even a solid piece of iron.
Anyway, my point was that some rotors don't incorporate a conductor, or even a winding.
Hence "proto-winding". The fact remains that heavy currents are induced in the squirrel cage (by the magnetic field generated by the stator), thus giving rise to its magnetic kinetic reaction.
I wrote not of "some rotors", but specifically of squirrel cage motors. Whatever, I have no dog in this fight; I offer my opinion only in the interests of clarity. [just my 2p's worth]
Exactly.
The only ones I have ever seen like that, have permanent magnets instead.
A rotor HAS to have a magnetic field. If it isn't an electro magnet it has to be a permanent magnet.
If it is an electro magnet it needs a coil through which current can flow, even if its a coil of just one conductor that is the squirrel cage.
Once again your showing your ignorance, I have already posted a link to a reluctance motor:
There are others.
As above, it doesn't need to be an electromagnet. Please enlighten yourself so as not to look like a fool.
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