Startrite 275 tablesaw motor issues

[Ttrees]

Hello folks
I'm testing out a new VFD today on a s1 motor for my TA275 tablesaw I'm souping up.
On opening up the terminal housing I found that dust was absolutely crammed into this space.
The cable gland that grips the cable was not pinching the cable atall .
Should I be concerned about opening the motor up to clean it ?
Can I test my new VFD just to see if it works ?
I'm not sure if the man I bought it off ever used it ...but did turn it on without a blade, to show me it worked.
I have taken the motor with mount plate off the cabinet, this will be left in this state for a while .
I have got the time to clean it ...I'm Interested in motors aswell ...
I might, someday end up with a fixed star wound motor, that needs to be converted to dual voltage .

I have no experience whatsoever in taking motors apart ..willing to research though
Thanks in advance

 

[Ttrees]

I tested it anyway, eager to see if the new VFD worked ... IT LIVES !!!
Its exactly like the last one, remember to do a parameter reset on these, sent from factory at 400.00HZ !
Really fast postage and good communication from discountdesignsltd.. all in all a little over a hundred quid.
I think this one comes with an extra green light inside I cant remember if the last one I got done that...

I was kinda hoping the fan would turn off automatically though, like the ones Jack Forsberg (Jack English machines)
has featured in his videos...
but I probably wouldn't have been able to afford the postage cost to here though.

I was looking for a VFD that can remember settings for two different machines but these only go up to 1.5KW
at the moment ...I needed a 2.2KW ...might use this one for a cyclone if they start making 2.2KW ones ..hopefully

I had to take the pulley off as it was loose ...must inspect this shortly ,just was focusing on the VFD first ...
I hope its not damaged (fingers crossed)
And I spent an hour looking for a cable gland when all I needed too do, was wrestle a larger grey cable sleeve
onto the smaller black cable ...this should be good now ...

Pics show motor terminals in 220/240V in low voltage mode Delta (triangle) arrangement.
and wires in VFD will have spade plugs attached when properly hooked up...
These need to be modified to fit in teeny VFD terminals ...
(Don't be a gorilla with these screws! especially the earth wires as its two going into this wee terminal)
And another cheer for Bob Minchin for his efforts on informing all of us, this can be done ...
Read his write up on induction motors ...and get yerself a proper machine for less 8)

Still would like to know if its a good idea to have a looksey inside the motor ???
You might see.. 'just some' of the sawdust that was in the terminal box next to the terminal lid !

Thanks
Tom

P.s, The comments on the pictures have disappeared.
As you can see these VFD's come factory set for 400Hz !!!!
This would cook your motor if you hit run, as it would be 8 times the speed of a 50Hz motor!

 

[deema]

On all my secondhand machines I've taken the motors apart for a clean out. Always lots of saw dust, and it gives a chance to check the bearings. Usually a simple task, apart from if the plastic fan won't come off the shaft! Some motor bearings are designed it be a drop in fit and tighten up as the temperature rises, so always open a motor up when it's cold.

 

[Ttrees]

Thanks Deema
I have replaced bearings on my bandsaw before ...so that advice makes sense ...
From what your saying I gathered dust is not too serious of a problem ..to run for a moment in testing a VFD out.
I think I will have a go taking apart this one so...
I suppose compressed air is the tool for the job ...I don't have a compressor ...
Will a brush do ? ...Is their anything you shouldn't do/touch/open ?
apart from disconnecting it :lol:
Thanks
Tom

 

[graduate_owner]

I had a vfd go defective some while ago so bought a replacement. In the instructions it said to keep out any dust and damp, and I suspect this was why my first one broke - it had a cooling fan which blew dust laden air through it . My new one is mounted inside a dust proof box, quite a large box to allow for air to circulate. It also has a temperature cut out switch. Might be worth you doing the same, unless it is already in a IP65 housing. Cheaper to make a box than buy a new vfd. I made mine out of steel cut from an old boiler casing.

K

 

[Ttrees]

Defiantly will be doing so ...just seeing if the magic blue shmoke came out of this one
I'm making the box from stainless steel ..It will be fun drilling out holes for the screws ...
I'm also making it with a rounded roof,because the dust sits on top of the one on my bandsaw #-o

 

[Ttrees]

I had a vfd go defective some while ago so bought a replacement. In the instructions it said to keep out any dust and damp, and I suspect this was why my first one broke - it had a cooling fan which blew dust laden air through it . My new one is mounted inside a dust proof box, quite a large box to allow for air to circulate. It also has a temperature cut out switch. Might be worth you doing the same, unless it is already in a IP65 housing. Cheaper to make a box than buy a new vfd. I made mine out of steel cut from an old boiler casing.

K

If it's one of these ones my last one stopped for no reason ...tried lots of stuff ,took it apart...nothing wrong.
Seen somebody done parameter reset but instead of setting PD 13 to 8... set to 1 instead .
This fixed the problem ..still runs great ! ...
Talked to the Chinese ..they said ..oh that's the old version

 

[Ttrees]

Took the motor apart...was surprised to see little, if any dust inside the motor
wired it up again and its still as smooth as it was ...
Don't know if their was enough grease on those bearings ?
Glad I took pictures, as I wasn't sure which orientation to place back either of the ends ...
The threadbar needed to be between the motor fins and align up with the fan cover afterwards .

Looks like I need to buy a motor pulley ...as it's about 1mm larger bore than the 24mm shaft in spots.
It looks a bit off center anyway ..
I need to buy or make a key for the shaft too ...
Is this motor shaft ok, or will their not be enough meat to tightly fit on the key ?
Will I need to fill this gap by welding it ?
Thanks again folks,
Tom

 

[Ttrees]

Looking up damaged motor keyways ...
It seems their might be a few ways of going about this ...
Firstly, I will be getting a new pulley...from quick searching it seems their common enough and not too expensive.
I have not tried to match the exact one ...will do a proper search later....
Might require buying two to match...

The Shaft
Seems like I could either make a custom key to fit, but welding up the worn part looks like a simpler idea.
Does this need to be an extra hard weld ?
I will be using an ark welder ...might see what the local engineering store has to offer in regards to rods for a hardened
weld ...
I probably wont be heating this up to mad amounts, but with an unknown rod I could be using ..I don't know if theirs any damage that could happen ?
On to buying a key ..Have not looked for one ...might be for buttons or maybe come with the pulleys or as an extra.
If not does this need to be tool steel ..I think I might have some stainless that might suit .
Seems like this is the best route ...If I can get a hard enough weld on there .
Thanks folks
Tom

 

[Myfordman]

Looking up damaged motor keyways ...
It seems their might be a few ways of going about this ...
Firstly, I will be getting a new pulley...from quick searching it seems their common enough and not too expensive.
I have not tried to match the exact one ...will do a proper search later....
Might require buying two to match...

The Shaft
Seems like I could either make a custom key to fit, but welding up the worn part looks like a simpler idea.
Does this need to be an extra hard weld ?
I will be using an ark welder ...might see what the local engineering store has to offer in regards to rods for a hardened
weld ...
I probably wont be heating this up to mad amounts, but with an unknown rod I could be using ..I don't know if theirs any damage that could happen ?
On to buying a key ..Have not looked for one ...might be for buttons or maybe come with the pulleys or as an extra.
If not does this need to be tool steel ..I think I might have some stainless that might suit .
Seems like this is the best route ...If I can get a hard enough weld on there .
Thanks folks
Tom

Thanks for your appreciation of my motor stuff!

If you are going to get a new pulley go for a taper lock type. They grip so much better and have less reliance on the key.
Whether you weld and re-machine is up to you but it needs to be accurate. Weld is a lot harder to machine than the shaft steel.
Otherwise hand file a custom key to fit the distorted keyway.

Bob

 

[Ttrees]

Thanks Bob
I thought the shaft would be tool steel of some description
I think I will reweld it so ...I have 6013 rods but unsure if these will be hard enough ?
I don't mind working extra hard metals ...I'm kinda used to it at this stage ...
so wouldn't mind getting a few rods that would make a harder weld .
glutton for punishment me
That's a relief
Cheers
Tom

 

[Ttrees]

So I took some measurements of the aluminum pulley .
There was a lot of variation taking measurement so I done the best I could ...
I thought it would be easy to get a pulley, after briefly looking on google images ...
But it seems as I first expected ..not so easy afterall.
I'm not even sure what this pulley is called ...double v pulley ...24mm bore ?
2 pulley ...twin pulley ?
I looked for info on videos and I watched 20min video of a man machining on for his lathe, but he didn't mention
what the dammed thing is called !
I looked into taper lock pulleys too ...these seem like their suited for bigger pulleys ...
Are these recommended for slightly out shafts ..I got some variants in measuring this also ...
I expect its ok though.... and if I fit a make and fit a key, ill make sure its a super tight fit .
I can drill out the bore myself if it comes down to it also .

On reading the pulleys on suppliers websites I see PCD and boss .
What are these referring to ?
Some of these websites are not very helpful atall, for a newbie to understand

Here's some pictures of the pulley in question
Thanks again folks,
Tom

 

[mindthatwhatouch]

I wouldn't weld up the shaft unless you have facility to machine it.
Much easier to make a key to fit.
Does the threaded hole for the bolt look original? The bolt is certainly not. Maybe you have non original pulley or someone had problems in the past. Usually pulley would lock on with key or grub screw only.

Is the keyway dished at the bottom (Woodruff key) or straight.

I shall try to find an image for a solution I have used in the past.

 

[mindthatwhatouch]

If you don't want to disassemble the motor a blast of compressed air works wonders, as you have it in bits I'd swop the bearings anyway.
Re pulley:Measure motor shaft and source pulley to fit. An engineering company will be able to team out existing pulley and fit a new sleeve to the boss ( round lump that measures 47.5mm on your drawing) perhaps a local amateur model engineer maybe able to help?
If you have access to milling machine or get engineering company to cut a new keyway opposite old one.
Fill old keyway, I used epoxy metal and rounded it off on a lathe, you could get it close enough with some filing though.
http://www.myronsmopeds.com/category/engine/top-end-hardware/
Sorry having trouble finding a picture. If you look at image top left under Woodruff key you can see a circular cutter for milling the slot.

Regarding the earth connections on the vfd. Just take a small earth wire to the nearest metal point and take the rest of the earth's from there, nut and bolt somewhere on the table saw or vfd enclosure if you are using one.

Hope this helps.

 

[Ttrees]

Thanks Mindthatwhattouch,
I would have no problem filing out the weld ...
I've done this kind of awkward stuff a lot before.
I did not think of machining the other side ...I would just weld and fill in again though
if I didn't get the results I wanted.
It seems like 6013 rods will produce a strong enough weld , but I'd like another opinion on this specifically
I will try and get a new pulley though, because there is about 1mm of variance measured from the
bore to the outside .
I suspect this could be why the shaft got mangled in the first place.
I think it might be cheaper to try and buy a pulley than get a machinist to machine a new sleeve for the "boss."(thanks)

The key has a flat bottom and the last 1 or 2 mm has a woodruff style end beyond where the key is.
I have no problem making another key .
I will lap one up on a granite plate .

I just tested the VFD to see if it worked ..I will be installing plugs on the end of these wires coming from the motor,
provided the cable will be long enough to go to where the vfd will be placed .
I will also be swapping out the power cable for a stronger one and maybe putting a protective cover around both too.

Thanks again
Tom

 

[Ttrees]

Hello again folks,
Just filled and filed the keyway slot ..
Didn't find the filing difficult nor did I find it any harder than the shaft....
I thought it would be a good idea to insert 13amp brass plug pins, with a ground bevel to the bottom of the keyway,
So as not to end up welding the bottom of the slot...
I also got some copper pipe and fitted it around the shaft not to end up with weld on that too...
Used 6013 hefty rods 3.2mm
What a disaster (hammer) never trying the copper thing again .....
Switched to 2.5 (if even that) skinny rods and they worked great ...no brass or anything used to protect shaft...
Just gonna use these wee skinny rods again, even if they are a bit temperamental to use.

Ended up probably taking the tiniest amount off the key during broaching attempt for fitting in spots,
I have a tendency to go one step forward, two steps back when I weld ... so left the keyway too tight to fit the key, as it
was probably worn at this stage.
Will be making a key in time .

I am going to try and see if the OD of the pulley is perfectly cylindrical and maybe get a machinist to bore out the off center hole .
I would try this myself although I think the drill would have a natural tendency to follow the path of least resistance .
I could probably file it out though if I made a tool for making witness marks to work to.....
I'm talking myself into this as I'm typing :roll:

I Might consider this if I can... (A) find a suitable stock for a centering marking bar to file to...
Then I could drill the hole bigger perfectly in the boss ...
(B) find suitable stock somewhere with a 24mm ID ...
I don't mind atall filing the keyway into it.

Anyone done this kind of thing before ? I would love to know where to find such a piece ...
Some car part or something scavenged perhaps.

I'm guessing I wont get any bother form the extra weight if I find steel substitutes...?
Would love to hear any tips of any sort .
Thanks folks,
Tom

 

[Ttrees]

Hi again
Looking at this pulley today it appears that the pulley OD is spherical, as it looks evident that their is a partial chamfer
on the bored hole .
Pondering about the motor pulley again, and thought of a way to get an accurate center mark
I've decided to make a radius marking gauge .
This will perfectly mark out a perfectly centered hole to file to .
Now to find some tube to make a sleeve for the shaft .
I mentioned previously that this pulley hole is about 1 mm too large ...
What is the usual sleeve size that a machinist would go for ...

Just the thinnest one could get away with ...
or a bit thicker that would not deflect with the press fit ?
I obviously have not made a key for this yet .
Have VFD on disposal to spin motor for very tight tolerance fit at whatever RPM

And I'm guessing that this keyway slot is indeed centered on the pulley....
I got the impression that it would not matter from this post ...
referring to the,make a custom key for worn slot comment
Thanks
Tom

 

[Ttrees]

I wouldn't mind seeing what designs of radius gauges that's out there if they exist ...
Might be handy even in woodworking ....
Whatever that is

Opinions sought
Thanks

 

[Ttrees]

Back again for another update
Got my center marking tool made, will score the line later on ..
Looks like I have to find some tubing of some sort, that's 24mm ID ...
I can turn it on the motor if its too thick and take it down to whatever thickness I need...
Would love to hear some old skool suggestions on doing this craic ...
Was thinking of a cheap oilstone or wood with autosol compound ...something along those lines,
Should be able to get a nice press fit this way.
I would love to know somewhere handy to scavenge this 24mm ID in ANY thickness.
There's no going back now :roll:
Looks like I could be shopping for a nice file for the job tomorrow
,any excuse for another tool !
I could nearly buy the collar if things cant be sourced :shock:

I can putter away at my VFD enclosure and mobile base in the meantime anyway
Thanks folks
Tom

 

[mindthatwhatouch]

Google skf speedi sleeve.