Centrifugal switch replacement

Can someone please help me - I am trying to fix a Newman Elf motor, specifically, replacing the centrifugal switch. I am trying to remove the cast collar section of the old switch off the shaft so I can slide on the new switch.
It appears it sits within a machined groove, I’m guessing, to hold it in the correct position. Problem is it looks like I have to remove the shaft from the other end. Do I have to remove the shaft by first taking off the part that the belt sits in and then slide it out?

I’ve tried to take off the bit that holds the belt by unscrewing the locking nut but still can’t get it to slide off? Maybe just stuck from years of grease and grot? I have given it a good spray with WD-40 hoping this might loosen it but still not budging.
My other option is to carefully angle grind through the switch collar to remove it??!! Not my preference

I’d much rather fix this than throwing it away as the rest of the motor is fine, and probably a whole lot better made than motors today. If anyone can help by giving a step by step instruction that would be appreciated as I can’t find anything online that shows or explains this.
thank you.

Hello Annalise,

Do you really need to replace it? These switches are generally quite robust and when they begin to develop faults it is usually a case of spark erosion on the points, oxidising the contacts . I suggest you do little more at this stage than get a piece of fine emery cloth or paper, doubled over to have abrasive faces both sides and slide it between the contacts. Now work it about to polish the faces, clean the area to remove loose abrasive and that should be sufficient.

If the closing springs have failed, rob the new switch and rebuild the motor. It might surprise you! Generally a good clean up in the area is also to be recommended and a drop of oil on the bearings would be worthwhile while you have the motor open.

Kind regards Brian

I don't kinow this particular motor but if it is a light alloy casting it might not come off.

I have seen motors that had light alloy features like bosses and fan blades in light alloy die-cast in place on the shaft. If you are making a diecasting mould it's not a big step to put the shaft in it and save an assembly step.

Robert.

As Brian has said try cleaning the contacts with 320 or 400 wet or dry paper folded double in a 1/2" strip. I take it the bit you cannot get off is the pulley ? Very careful use of a gear puller may work. When fitting the centrifugal switch the position of the various parts is critical to it's proper operation = if the start windings stay on for too long then they will soon burn out. Good Luck Noel.

Positng pictures of the part that you are trying to remove and the other end of the shaft that you need to remove would be helpful.

Les.

Here are a couple pics to show the part of the switch I am trying to remove. The small alloy arms holding the springs were broken, hence the need to replace. It does look like it may have been cast in place?

It may be beyond me to fix!?

Probably best to remove the rotor completely, options then to try mounting in a press with a plate behind the part you want to remove to check if it's a press fit, if not can you drill and tap for a screw to fix the spring on ?

Emgee

Perhaps a picture of the new switch to compare would help us here

Brian

That does look like one of the cast in place rotors I mentioned earlier.

Robert.

Any chance that the new switch could be dismantled and re assembled onto the existing arms?

o e. make a working switch out of nthe parts available?

Howard

I agree with the cast in place thoughts by Robert. I would see just how similar a replacement switch is to the original and only remove the old mount if there was no other way, and it would get turned off and a new mount made.

Looks to be a good set of winding, all is not lost, as if you bring out the pair of wires which went to the centrifugal switch, you could use a freezer relay or even a toggle switch. The toggle switch would be manually operated in conjunction with the normal mains switch. When motor were not so plentiful as today it was amazing what people did to power workshop machines. john

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Edited By duncan webster on 24/07/2023 18:03:20

What has actually broken ? The wings on the centre look good. If the anchor for the springs has failed then drilling and tapping the centre and making a new fixing may work. Bear in mind that there are 2 common motor speeds and therefore 2 switches, 2 pole and 4pole. See my earlier comment on positioning and correct operation as this could easily cook the windings if wrong. Newman were good motors it would be a shame to see it burnout for the sake of the start switch. If you know what your doing then Johns idea will work though a push button is safer,It may be cap start so the whole start circuit must be switched, you only need the start windings for less than a second in most cases. Noel.

Thank you for all the suggestions. This is the new switch. Its construction is different to the original switch - the arms that hold the springs. On the old switch they (the arms) were quite delicate and ‘pegs’ on the ends of the arms slotted into a grooved channel on the collar of the Bakelite. It was one of the arms that was broken, requiring replacement of the switch.
the windings are good and all else is functional. The wires just needed wrapping with insulation tape as the rubber coating was perishing due to age.
the new switch has a locking nut at its base to hold it in place on the shaft. It appears I’ll have to try and remove the cast piece of the old switch.
‘The motor is for a cement mixer so I’m not sure that I can add a relay etc and fit it all under the motor cover (plus this might be a bit beyond me)!

Appreciate everyone’s help!