# Capacitor problems, advice please.



## t8hants (20 Nov 2020)

I have Compton Parkinson 1/3HP motor where the capacitor has clearly failed.
I can start the motor turning by hand in either direction, but once it is spinning the speed is a fraction of the expected 1425rpm. 
Is this a symptom of the same failed capacitor which looks ancient, or is there something else amiss as well?
Thanks Gareth








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## minilathe22 (20 Nov 2020)

I wonder if you remove the capacitor temporarily, whether the motor now runs at full speed? (with the jump start of course). If not then it implies there is more than just the capacitor at fault.


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## Racers (20 Nov 2020)

The cap is essential to the motor running at the correct speed. 

Pete


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## artie (20 Nov 2020)

I thought my saw was down on power and, on testing the cap found it to be 16 uf instead of the quoted 20 uf . The guy who tested it called it a run capacitor, I asked him since I had always thought it a start cap. He said it played a part in running also.
I replaced it with a new one and it made no difference.


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## MusicMan (20 Nov 2020)

Some motors have separate start and run caps, some have one that combines the functions. I recently had to replace one on a bandsaw. At first I could make it run by jump starting it, but the speed and power were low. After replacing the cap it worked as new. But make sure you get one to the original specification.


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## t8hants (20 Nov 2020)

MusicMan said:


> Some motors have separate start and run caps, some have one that combines the functions. I recently had to replace one on a bandsaw. At first I could make it run by jump starting it, but the speed and power were low. After replacing the cap it worked as new. But make sure you get one to the original specification.


That is part of the problem, there is nothing on the prehistoric thing to indicate what values it made to.


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## porker (20 Nov 2020)

There are tables to determine the rough values. The tolerance of older caps was pretty poor anyway with +/-20% not being uncommon. I would pick one that is close with a voltage rating that exceeds the voltage you are using.

Take a look here to calc the values for your motor link


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## EddyCurrent (20 Nov 2020)

If the centrifugal switch contacts are not making correctly when the motor is at standstill then the capacitor will not be in circuit.
It could also be one of the windings in the motor, they have a start and run winding.
The capacitor puts the start winding out of phase with the run winding and that's what makes the motor start in the correct direction.
We used to learn the word CIVIL as an aide memoire. 
When it's capacitance (C) the current (I) leads the voltage (V)
When it's inductive (L) the current (I) lags the voltage (V)


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## johnbs (21 Nov 2020)

t8hants said:


> I have Compton Parkinson 1/3HP motor where the capacitor has clearly failed.
> I can start the motor turning by hand in either direction, but once it is spinning the speed is a fraction of the expected 1425rpm.
> Is this a symptom of the same failed capacitor which looks ancient, or is there something else amiss as well?
> Thanks Gareth
> ...


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## t8hants (21 Nov 2020)

Will do later this afternoon, if that helps.


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## t8hants (21 Nov 2020)

This the label on the motor


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## guineafowl21 (22 Nov 2020)

That plate unfortunately doesn’t help much. Are you sure the capacitor markings aren’t just painted over?

For less than a tenner, think this is worth a punt:





First4spares Universal Electric Motor Start run Capacitor Microfarad 50UF (Spade Connector / Tags): Amazon.co.uk: Large Appliances


First4spares Universal Electric Motor Start run Capacitor Microfarad 50UF (Spade Connector / Tags): Amazon.co.uk: Large Appliances



www.amazon.co.uk





Get the 50uF one.

Assuming the cap isn’t a combined start/run (more than two terminals), this should do the trick.


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## t8hants (22 Nov 2020)

Luckily for me its a two cable capacitor, with some very ropy wiring, so could well do with a change, thank you for the info'


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## EddyCurrent (22 Nov 2020)

If it's a run capacitor it should be rated at 400V AC, if a start then around 250V AC

These are the ones from my Startrite bandsaw
Motor
Brook Crompton
REF HQD562TFHPCNADZ
H5A16752
FLA: 6.6
Watts: 1100
RPM: 2850


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## t8hants (22 Nov 2020)

I have ordered the one suggested by Guineafowl21, which hopefully will prove correct, but there are no markings on the original at all.


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## EddyCurrent (22 Nov 2020)

Assuming it is the capacitor at fault, the one you ordered looks like it well might do the job.


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## Ollie78 (23 Nov 2020)

A small note. 
I had a problem with a machine not working, I thought I checked everything, twice. So had the motor checked, changed the capacitor. 
Turned out that the wiring inside the plug was good enough to indicate 240v but was holding on by a thread inside so could not provide any actual power to start it up.

Ollie.


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## t8hants (23 Nov 2020)

Ollie78 said:


> A small note.
> I had a problem with a machine not working, I thought I checked everything, twice. So had the motor checked, changed the capacitor.
> Turned out that the wiring inside the plug was good enough to indicate 240v but was holding on by a thread inside so could not provide any actual power to start it up.
> 
> Ollie.


An interesting incident Ollie, the motor will need rewiring anyway, as if it starts to turn normally I want to install it in my ML8, since the original smoked itself.


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## t8hants (25 Nov 2020)

The capacitors as recommended above have come, somehow I ordered two. However they are marked 'run' and have four terminals. The motor now runs at full speed provided I kick it off by hand. While striping off the old tin can capacitor I found the word 'start', presumably that is the type required, with two terminals as there are only two wires coming out of the old one. There didn't seem to be a combination of the four terminals that would act as a start only mode, so I presume I have to get rid of these new ones?


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## guineafowl21 (25 Nov 2020)

t8hants said:


> The capacitors as recommended above have come, somehow I ordered two. However they are marked 'run' and have four terminals. The motor now runs at full speed provided I kick it off by hand. While striping off the old tin can capacitor I found the word 'start', presumably that is the type required, with two terminals as there are only two wires coming out of the old one. There didn't seem to be a combination of the four terminals that would act as a start only mode, so I presume I have to get rid of these new ones?


As far as I could see from the listing, the four terminals are really just two terminals doubled up.

A run cap is the same as a start cap, but usually lower value and rated for continuous duty. In other words, you should be able to use a run cap as a start cap, as you are doing. 

So the cap you have should be fine. The next thing to try is adding the second cap in parallel with the first, which will double the effective uF value. If all works, you can either leave it like that or exchange for a 100uF one.

If not, next stage is the centrifugal switch in the motor - can you hear it click as the motor comes to a stop after running at full speed? Pull the back off the motor and examine the switch mechanism, wires and contacts.


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## t8hants (25 Nov 2020)

putting the capacitors in parallel, just blew the fuse, but I do hear the motor go click as it runs down.


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## guineafowl21 (25 Nov 2020)

t8hants said:


> putting the capacitors in parallel, just blew the fuse, but I do hear the motor go click as it runs down.


Extra capacitance causing more inrush current. Centrifugal switch next, then.


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## t8hants (25 Nov 2020)

Sadly again all greek to me what should I be looking for by way of a fault.. I have googled centrifugal switch to see what they look like.

Edit, I have had a look at a couple of videos on centrifugal switches, so I will try and see if I can sort that out, if not probably a new motor after Christmas.


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## EddyCurrent (25 Nov 2020)

Do you have a multimeter ?
As I mentioned earlier, before you bought the capacitors, it could be the centrifugal switch contacts or the start winding itself at fault.
Using the diagram near the bottom of the page here; Compare Split Phase Induction Motor and Capacitor Start Induction Run Motor
it is possible to test the switch and winding without breaking the motor apart.
Obviously do not energise the motor while testing and do not have the capacitor connected. Just hand turn the rotor as fast as possible by hand to see if the switch opens and then closes at rest.


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## Chris70 (26 Nov 2020)

You could always measure between terminals for resistance, ie, perform a continuity check. Any terminals with zero, or near zero, ohms resistance are connected, that is, electrically speaking they will be one and the same terminal. Measuring between terminals which exhibit a high, then decreasing, resistance are not connected to each other, that is, they are the true capacitor terminals. (The reason the resistance is initially high then falls is that your ohmmeter has a battery which is effectively charging the capacitor). I hope this helps, as the wally on Festool loves to say!


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## gmgmgm (26 Nov 2020)

Definitely check the windings' resistance, which is very easy: How To Test and Check Single phase Electric Motors

If you are really pulling your hair out, consider a capacitor meter. I had a few "motor problems" a couple of years ago and bought a capacitor meter. About £30, and it tells me the uF for each capacitor and whether it's good. Very handy to have for these sorts of problems. 

Once you know your windings are good, and the capacitors are good, then it's probably the mechanism to switch from start to run i.e. your centrifugal switch (or in other cases a relay e.g. potential/back-EMF).

Ultimately the wiring layout for a start/run capacitor setup is pretty universal, and there are not many factors at play.


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## johnbs (27 Nov 2020)

If you open up the terminal housing, can you see four terminals as shown in this document? Hopefully marked A and Z pairs? 
John


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## guineafowl21 (27 Nov 2020)

Chris70 said:


> Measuring between terminals which exhibit a high, then decreasing, resistance are not connected to each other, that is, they are the true capacitor terminals. (The reason the resistance is initially high then falls is that your ohmmeter has a battery which is effectively charging the capacitor).


It’s actually the other way around - measuring a capacitor on resistance setting gives a low reading that rises. We’ve hopefully eliminated the cap as a problem.


t8hants said:


> Sadly again all greek to me what should I be looking for by way of a fault.. I have googled centrifugal switch to see what they look like.
> 
> Edit, I have had a look at a couple of videos on centrifugal switches, so I will try and see if I can sort that out, if not probably a new motor after Christmas.


You’ll have to open the motor up. On the rotor (spinning part) there should be an obvious switch with a spring and flyweights to pull it in and out of contact. The contacts might need a clean, or there may be a wire off. Take some pics!


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## t8hants (27 Nov 2020)

I have put my multi meter set at 200 ohms on the original capacitor and the new one. The original capacitor reading starts at 1 and counts down to 0.002 where it stops, as does the new capacitor when the terminals are paired in one way and remains static when connected the other way.
Am I right in thinking the old capacitor is actually functioning as it seems to behave the same as the new one?


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## guineafowl21 (27 Nov 2020)

t8hants said:


> I have put my multi meter set at 200 ohms on the original capacitor and the new one. The original capacitor reading starts at 1 and counts down to 0.002 where it stops, as does the new capacitor when the terminals are paired in one way and remains static when connected the other way.
> Am I right in thinking the old capacitor is actually functioning as it seems to behave the same as the new one?


Forgive me, because I don’t know your experience with multimeters, but that doesn’t sound like you’re reading it right.

The 200 ohm range wouldn’t read down to 0.002 (that is 2 milliohms*), and the scale would count up, not down on a new capacitor. If you quickly switch the probes, the reading would go negative, up to 0, then rise to over limit (“0L”, or sometimes “1.”)

Given your description of the original cap as ‘ancient’, I thought it best to eliminate that as a cause by replacing it. It’s possible the old cap has drifted up or down in value, or varies with temperature, or many other things. You really need a capacitance meter and leakage tester to check.

*An implausible level of precision for that range. And the meter leads alone would have a resistance of at least a hundred times that.


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## Phil Pascoe (27 Nov 2020)

While you knowledgeable people are here, what do I do with this one? I'm fairly sure it's the capacitor that's the problem but I don't want to wreck this one if it's not. The innards are reluctant to come out so I can't see the terminals. Would a replacement be pre wired? There are only two wires (cores) from it.


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## guineafowl21 (27 Nov 2020)

Phil Pascoe said:


> While you knowledgeable people are here, what do I do with this one? I'm fairly sure it's the capacitor that's the problem but I don't want to wreck this one if it's not. The innards are reluctant to come out so I can't see the terminals. Would a replacement be pre wired? There are only two wires (cores) from it.
> View attachment 97270


That looks like quite a low value (16uF) - are you sure it’s not a run cap? Easiest thing is to replace it, as they are cheap compared to the overall machine. They usually come with spade terminals, so if your cap is hard-wired (which is a bit silly), then you’ll need to cut the wires and crimp some on.

Main ratings to follow are 450Vac and 16uF, motor start/run cap.


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## t8hants (27 Nov 2020)

My experience with multi meters is shall we say basic, but attached are the photos taken of a repeated connection of the old capacitor. 1 being with it on and unconnected 001 being the value with the thing connected to the capacitor, swapping leads or terminals makes no difference to the indicated value.


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## Racers (27 Nov 2020)

Is it a 4 terminal cap? Because it sounds like you are measuring the internally connected terminals giving you the low resistance reading.

Pete


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## guineafowl21 (27 Nov 2020)

t8hants said:


> My experience with multi meters is shall we say basic, but attached are the photos taken of a repeated connection of the old capacitor. 1 being with it on and unconnected 001 being the value with the thing connected to the capacitor, swapping leads or terminals makes no difference to the indicated value.


Ok, it’s on the 2000 ohm range. The left picture is reading over limit, ie open circuit. The right-hand picture suggests 1 ohm. If this is the true, stable reading, your capacitor is reading as a 1 ohm resistor, and if so, can be considered short circuit.

I assume the cap is disconnected from the motor, in which case either the cap is dead or your meter is.


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## guineafowl21 (27 Nov 2020)

Racers said:


> Is it a 4 terminal cap? Because it sounds like you are measuring the internally connected terminals giving you the low resistance reading.
> 
> Pete


Cross post - good point!

With all due respect to the OP, this is why remote diagnosis is so hard, and why I suggested just replacing the cap.

@t8hants I sense you’re reluctant to open the motor up. Do you want us to explain how to test the centrifugal switch without doing so?


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## t8hants (27 Nov 2020)

The old capacitor is a two terminal with the readings pictured (it was disconnected from the motor). The new capacitor is a four terminal version, connected to the multi multi-meter one way it remains static on 1, connected the other way the m-m behaves exactly the same way as the old capacitor, no settings were changed.


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## guineafowl21 (27 Nov 2020)

t8hants said:


> The old capacitor is a two terminal with the readings pictured (it was disconnected from the motor). The new capacitor is a four terminal version, connected to the multi multi-meter one way it remains static on 1, connected the other way the m-m behaves exactly the same way as the old capacitor, no settings were changed.


For the new cap, do you mean [_001] on the display, or [1___]?


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## t8hants (27 Nov 2020)

The meter starts at 1 when switch on, and will drop down to 001 when connected to the new capacitor, as per photos, the new and old capacitors give the same result.


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## guineafowl21 (27 Nov 2020)

t8hants said:


> The meter starts at 1 when switch on, and will drop down to 001 when connected to the new capacitor, as per photos, the new and old capacitors give the same result.


An earlier post suggested [1___] one way and [_001] the other on the new cap. You should make sure the new cap is connected using the terminals that give a stable [1___] reading.

[1___] is a normal reading for a capacitor, but it won’t tell you good or bad. A good meter will spot the count up, but yours must have a very slow refresh rate. You will also see [1___] on a knackered cap with some capacitance left. You are performing an inadequate test, with a cheap meter, and without the knowledge to interpret it. I rather wish we hadn’t gone down that road at all.

Please stop fiddling with the new cap and address the next stage in the diagnosis, which others have been pushing you towards. Do you want to:

A) Test the centrifugal switch electrically
B) Open up the motor and inspect everything directly.

My suspicion is that you’ll need to do B anyway.


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## Racers (27 Nov 2020)

A few microfarad capacitor probably won’t give much so a reading when testing with a digital multimeter try connecting the way you get no readingi and then reversing the connections, and try the diode setting next to the 200 ohm setting.

Pete


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## t8hants (27 Nov 2020)

quite happy to put the capacitors to one side, but I only get a reading of 1 when the meter is on, but disconnected from the capacitor, the moment it is connect that is when the reading will drop to 001. I do not get a stable 1 with the meter connected to the capacitor. 
With the circuit diagram of the centrifugal switch, I remain unclear to which terminals on the motor to connect the meter.


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## guineafowl21 (27 Nov 2020)

t8hants said:


> The new capacitor is a four terminal version, connected to the multi multi-meter one way it remains static on 1,





t8hants said:


> I do not get a stable 1 with the meter connected to the capacitor.


This is why I’m confused.

The [1___] means over limit (open circuit) and is nothing to do with the number 1. 

With the motor unplugged, remove the capacitor and probe the two resulting connections with your meter set to 200 ohm range. Tell us the reading. Be sure to differentiate [1___] from [_001].


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## EddyCurrent (27 Nov 2020)

Referring to the diagram, I'm assuming your motor is similar.

The capacitor normally connects to D and A
The mains supply to the motor normally connects to B and C

*With the motor disconnected from the mains and the capacitor removed;*
Testing the start winding.
1.Connect the meter to C and D and measure the resistance (Ohms)

Testing the centrifugal switch
2. Now connect the meter to B and A and measure the resistance, it should be zero ohms or very very close.
3. With the meter still connected to B and A, spin the motor as fast as possible by hand and the reading should go to infinity then back to zero when you stop spinning it.


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## johnbs (2 Dec 2020)

I'm desperate to see this resolved! Please OP, could you post a photo of the new cap's terminals? 
Then set multimeter on 200 ohm range. When you have the new cap's terminals correct, you should get the following pattern:
Meter not connected: overflow = 1___​Meter connected: starts low and *rapidly increasing* reading until terminating in *overflow *again​Meter REVERSED: ditto but will take longer to overflow. *​This assumes the new cap is not faulty and you've got the right terminals, which is not an unreasonable assumption. 
You don't need to dismantle the motor to establish if the centrifrugal switch is OK. Look at the photo I posted, if you have four terminals , use the meter on 200 ohms again to check continuity A1 to Z1 or equivalent .
John
* reason I've added this step is if the cap has charged to the multimeter's maximum sense voltage, you will get an overflow immediately when connecting the meter. Reversing the meter means you guarantee that the cap has to be charged by the contant current which the meter puts out (probably 1 or 10mA on 200 ohm range)


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## t8hants (2 Dec 2020)

I will try and do that tomorrow John, the wife has had a few days off, so I have been out of the workshop doing the larger chores for her.


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## t8hants (3 Dec 2020)

I have taken the series of photos requested. I have discovered that for my first set of readings posted above I had the meter set at 2000, not 200 ohms, my bad!!

Photo 1 is the setup unconnected and reads 1,
Photo 2 is a connection across the plastic ridge and the reading remains unchanged at 1, the same result is given if the terminals are connected diagonally across the ridge and remains at 1.
Photo 3 is a connection on the left hand pair of terminals and gives a reading of 1.9, and it appeared to be stable.
Photo 4 is the right hand pair of terminals connected and they gave a stable reading of 1.3.
Photo 5 shows the old 'tin can' capacitor and it reads 1.9.

I hope that clarifies the mud.
Gareth


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## guineafowl21 (3 Dec 2020)

Your old cap is shorted.

The new cap is behaving normally, but only when connected correctly, ie across the bridge (as in P2.jpg). The terminals are linked internally, paired L and R as you have labelled.

If you connected the new cap as per P4 or P5, it would not have worked.


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## t8hants (3 Dec 2020)

I have connected the capacitor correctly with the result the motor now runs at full speed clockwise, but only if kicked off by hand.
As it slows to a stop, there is a distinct 'click' and the shaft gives a slight twitch.
Several start attempts produced the same result, so I presume I must now look at the centrifugal switch?
Which end will it be under, the wiring board or the pulley end please?
Sorry to be a PITA.
Gareth


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## Ttrees (3 Dec 2020)

This is a very interesting thread
I can't advise anything, but will mention tape or draw a line down the motor so the end bells will realign again.
it could be trickier otherwise if they are a tight fit.


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## guineafowl21 (3 Dec 2020)

t8hants said:


> Sorry to be a PITA.


You’re not! You just got a bit hung up on testing the capacitors on resistance mode, which is interesting but not very useful.


t8hants said:


> Which end will it be under, the wiring board or the pulley end please?


If you follow @EddyCurrent ’s post #44 you can test as per his diagram, with the meter on 200 ohm range.

If you want to dismantle, the switch is usually on the back end, ie not the pulley end. Good advice from @Ttrees to draw a line along the motor.


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## t8hants (4 Dec 2020)

Just to help things along I have taken a photo of the wiring connections as found on my motor ( I didn't wire it up myself), but this is just to check the motor is wired up correctly. Cables I name as 'motor cable' simply come from inside the motor and AC as from the 13amp plug.
Starting from left to right and numbering in that order
Post 1 has the AC negative wire, a connection to the capacitor, and the long red motor cable seen in the photo.
Post 2 has two motor cables coloured black and red
Post 3 has the other capacitor connection, and the AC positive
Post 4 has the AC Earth cable.
It is also possible that the AC Negative cable was shorting on post 2, bare wiring was very close to the terminal.


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## guineafowl21 (4 Dec 2020)

If what you say is correct, your cap is wired across the mains. This is not correct and you should really start again with the wiring. At this point I strongly recommend you take it to a motor shop or electrician. It’s possible a change of cap connections would get you going, or we could guide you through identifying the motor connections and rewiring, but it would be somewhat painstaking. A motor in this state should also be meggered for electrical safety.

Sorry, I had assumed the motor was working, then stopped, so the wiring was most likely correct.

Please reconfirm the connections, because if your old cap was shorted and across the mains, it should have just popped the fuse.


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## t8hants (4 Dec 2020)

_Sorry, I had assumed the motor was working, then stopped, so the wiring was most likely correct. _
Unfortunately I can't remember the history of the motor, I may well have inherited from my father the better part of 25 years ago and along with with several others, it just sat waiting for the day it would become useful. 
The wiring looks very unimpressive and will need to be neatened up, if the motor is Ok. 
As stated with the new capacitor the motor will run nicely, if started by hand. I was also hoping for guidance on which of the terminals to use in doing the test as mentioned above, before i delve into its internals.


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## guineafowl21 (4 Dec 2020)

t8hants said:


> _Sorry, I had assumed the motor was working, then stopped, so the wiring was most likely correct. _
> Unfortunately I can't remember the history of the motor, I may well have inherited from my father the better part of 25 years ago and along with with several others, it just sat waiting for the day it would become useful.
> The wiring looks very unimpressive and will need to be neatened up, if the motor is Ok.
> As stated with the new capacitor the motor will run nicely, if started by hand. I was also hoping for guidance on which of the terminals to use in doing the test as mentioned above, before i delve into its internals.


If you’re determined, then I’m happy to help, but it might not be easy.

Would you mind reconfirming the connections? For example, I think I can see a wire going into the motor from post 3, which is not mentioned. Also, as I say, it should have popped the fuse with the old cap if connected as per your description. Pull the capacitor wire down so we can see what’s going on.

Ideally, draw a diagram of the connections and take a photo.

Also note, there is no such thing as AC positive and negative. It’s live (or line) and neutral.


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## t8hants (4 Dec 2020)

Well spotted, I took stronger glasses and there is indeed a black motor wire attached to post 3, which is exactly how it was marked originally, as I cleaned the white smudge alongside it, so the posts appear to be originally marked 1,2,3.
I have attached a wiring diagram as it appears to me, apart from the live and negative cables which are colour striped, the colours are correct.
As I don't know where the 'motor' wires connect to I have just marked them as such.
I have no desire to delve into the motors internals unless it cannot be avoided.

BTW thank you for taking the trouble to help.


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## guineafowl21 (4 Dec 2020)

It looks like the incoming neutral should go to post 2.

Before you do this:
1. Make sure it’s unplugged.
2. Disconnect the capacitor.
3. Measure resistance, on 200 ohm range, between posts 1-2,1-3, and 2-3.


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## t8hants (4 Dec 2020)

I have, I hope followed your instructions correctly and taken have the measurements, with the wiring unchanged.
We have readings of, although they all fluctuated slightly.
1-2 = 26.8, 1-3 = 32.9, & 2-3 = 7.1 .
I took pictures of all three set ups to confirm I did the test correctly.


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## guineafowl21 (4 Dec 2020)

That fits with the sketch I’ve made below. You might notice that the first and last readings sum up to the middle one. You were measuring the start winding, then both, then the run winding (I hope).

Again, with the motor unplugged, reconnect the capacitor, then move the neutral connection from post 1 to post 2. Put on a new crimp connector if you have one. If not, maybe just strip the wire and clamp it under the nut. 

With the motor steadied somehow, plug in and switch on, being ready to switch off again quickly. If all goes well, it should run.


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## t8hants (5 Dec 2020)

Success, the motor starts and spins!! I owe a big thank-you to the help I got on here, but especially to Guineafowl21, for taking me through the diagnostic process stage by stage.
Now I can marry it to my saved from scrap Myford ML8 and enter the wonderful ( I hope) world of wood turning, although I am slightly hampered by my dear wife who doesn't like turned objects that much, Oh well. Still once again thank-you one and all.
Gareth


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## guineafowl21 (5 Dec 2020)

t8hants said:


> Success, the motor starts and spins!! I owe a big thank-you to the help I got on here, but especially to Guineafowl21, for taking me through the diagnostic process stage by stage.
> Now I can marry it to my saved from scrap Myford ML8 and enter the wonderful ( I hope) world of wood turning, although I am slightly hampered by my dear wife who doesn't like turned objects that much, Oh well. Still once again thank-you one and all.
> Gareth


Well done!

That was easier than I thought it would be - thankfully we didn’t have to disconnect all the windings and start from scratch.

A couple of final jobs:
1. Measure resistance (200 ohm range) between the earth pin of the plug, and the motor casing. Should be low.
2. Measure between each of the terminals (1,2,3) and the motor casing. Should be high [1.__].

Ideally, these tests would be done with a high current earth bond tester, and a megger. Better than nothing, though.


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## EddyCurrent (13 Dec 2020)

Great results, kudos to guineafowl21. 
I have just returned from hospital following a heart operation which is why my participation in this stopped suddenly, sorry for that.


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## t8hants (13 Dec 2020)

I think you can be excused for not continuing your participation in this thread and I wish you a full and speedy recovery. I am waiting until silly season is over then I will get myself a modern stop start switch for the lathe and wire it in properly. The antique MEM tin box switch I had in stock now looks a bit dubious, and I have no idea what it is rated as as its labels are almost unreadable now.


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## Jos7000 (15 Dec 2020)

These folk might be worth contacting, past experience has shown me that electrical engineers often just enjoy the chance to stretch their memories. 





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