Help with mains electric motor

[Rex]

Please don't take this as being rude, but following the post makes me believe the questioner is not familiar with mains wiring. Your life depends on knowing what you're doing, and asking these questions suggests otherwise. Please ask someone else to look at it.

Yep, my thoughts exactly. Taking advice (or indeed giving it) from Net posts is a recipe for disaster as you can't know the abilities of the giver or recipient.
No offense intended to any poster here, but 230V is dangerous stuff.

[limeyrob]

I spent may years as an HSE inspector on offshore rigs. We were strongly against high voltage testing and advocated continuity and low voltage where ever possible.  There were just too many ways for it to go wrong and once you are up to 240v its very unforgiving.

[RDfella]

It's even more fun with 3 phase. Like when they changed the colour coding, so black (originally neutral) is now live, and blue (originally live) is now neutral. And fun like Star / Delta (mechanical switching) on my Holbrook lathe, where of the three contacts that close
for each part, only two switches feed the motor - the other live is fed direct to motor and the 3rd 'finger' is to switch the solenoid for engagement.
I'm no sparkie, but don't play with things unless I know what I'm at.

[Rex]

The simple basic colours for three phase used to be red, yellow, blue, and black for the neutral, and had been for decades.
Now it's the somewhat odd brown, black and gray combination and blue for the neutral.
Thanks EU, for taking a sensible system and making it worse, just for the sake of change.

[limeyrob]

Don't forget to add the Chinese gear that turns up marked CE with red, black and white wires
We had a sparky killed on one of the rigs: He isolated the one cabinet in a row, turned round to answer a call, then put his hand in the live cabinet next to it.
On my last tip in August (I'm retired but still do audits) I went round every HV electrical room and made sure they had isolation certs, insulating step ladders, rubber mats and rescue hockey sticks.  This one was good but they do sometimes use ally ladders with 2KV work in Norway and get very huffy when I explain that's a no-no in the UK.

[Greybeard]

I'm not dead yet! 😜.
I finally got the time to play with the motor from the table saw.
As you can see I strapped the motor down to a workmate
After connecting a power lead to the given connections and even spinning the fan on the shaft the motor did nothing. I then stripped the motor. The motor is brushless. I used my multimeter to check continuity in the stator windings - they are open circuit on all resistance settings. There is no sign of overheating in the windings and no smells. I reckon that's the end of the road for the saw.
Thank you to all who contributed to this question 👍

[limeyrob]

I'm surprised they are open circuit, is there any other explanation for the readings?  They are thick conductors and there's no obvious burning.

[trevinoz]

It appears that there is no centrifugal switch and the capacitor does the starting.
I have found that a faulty capacitor will prevent this type of motor from starting.
Have you had the capacitor tested?

[berger]

if the coils are open circuit it suggests there is a bust somewhere , not one you have in a bra 

[chaterlea25]

Hi GB,
There is probably a thermal fuse strapped to the windings inside one of those sleeves?
If you locate it it can be bypassed to test the windings, 
I was able to buy a new one for the coffee milk heater/frother for a few cents.
But had to buy other items to make the postage worthwhile

John

[limeyrob]

Good point, a friend was about to throw out a 2 year old washer dry after the repair said it was burned out and uneconomic to fix. It was expensive and she was petty upset.  I said I'd take a look not expecting success but under the heater element was re-settable thermal trip. No mention ins the instructions and the repair guy didn't (or chose not to) know about it.
Those windings look to good to be burned to open circuit.

[Swarfcut]

 On my compressor a few months back, the Chinesium  bolts on the end plate on the motor failed allowing the shaft bearing carrier to move and the rotor to kiss the field coils, snagging on the very fine wire windings, an impossible fix, but easy to see the problem. Almost designed to fail. I'd agree, if the coils don't look burned  it's well worth searching for a simple physical fault. No reason why a rotor should fail, so a failed field winding is to be expected on any spares or repair offering with an induction motor like this one if the start capacitor is good.

 Came across these folks via Daily Telegraph's  Honest John website. Might be of interest.
     

    https://robsonandfrancisrewinds.co.uk/veteran/index.html

   
   Swarfy.

[Greybeard]

Hi GB,
There is probably a thermal fuse strapped to the windings inside one of those sleeves?

An excellent suggestion John. I'll have a poke around 👍