On 21 Sep, 16:29, robgraham wrote:
On 21 Sep, 14:19, "Andrew Mawson"



wrote:
"robgraham" wrote in message

....
On 21 Sep, 08:17, "Andrew wrote:
"robgraham" wrote in message

.... On 20 Sep, 22:41, "Andrew
wrote:
"robgraham" wrote in message

....

I've the task of running a Harrison wood turning lathe with a
3/4
hp
3ph motor on single phase.

I've an electronic box which converts 240v single phase to 240v
3
phase and I've had running a modern 3ph motor, but the motor
from
the
Harrison lathe ( Griphon from Brook Motors) is an old one and is
connected in star configuration for 415v operation.

Has anyone tackled taking an older motor such as this apart to
get
access to the coil ends and reconnect as a delta connected
motor?
I
can't imagine that motors of this age - possibly 60 years old -
are
that much different in build but I don't have quite the
confidence
I
had in my teenage years for taking things apart and getting them
back
together again successfully so I'm looking for some words of
encouragement!!

Thanks
Rob

Rob,

Yes I've done it - it's fiddly and if the coils are shellac'd
(which
they probably are) it makes getting the thing apart 'interesting'.
Make sure that you use wire and sleeving that will stand the
temperature and both lace it and shellac it to ensure no fretting.
The
bigger the motor the easier it is. Smallest I've done was the suds
pump on a Colchester Student lathe - 1/6 hp iirc - all a bit tight
in
there!

AWEM

Hi Andrew
Do I take it that you withdraw the rotor and work inside without
removing the coils ? Shellac I have in the form of I use for French
Polish - I take it that's the correct form? But what is suitable for
the re-lacing ?

I was just thinking that gentle application of meths will ease off
the
existing shellac.

Many thanks - these are just the words I was looking for.
Rob

Yes, rotor out and work on the coils. I wouldn't use meths - itmay
go
further than you want - just gentle teasing out with a scalpel
blade.
Use strong cotton for lacing, not plastic

AWEM

Back again already, sorry ! * I've released the through bolts and
tapped out the end plate but ..... the bearing is holding it and the
rotor in. *Do I need to take off the pulley block and the plate at the
front end -(I'll have to go and cadge a puller from the works up the
road a bit) and then do I have to arrange some sort of pressing action
in order to get the shaft clear of the rear bearing ?

Cheers and thanks

Rob

You may be able to get at the star point without pulling the
armature - do a bit of investigation before further dismantling

AWEM

I'm hoping so but I still have the problem of getting the plate off at
the end which carries the terminal block. I can see the coil ends by
taking the terminal block off - only see - but I can't progress
without separating the shaft and the bearing so that I can get the end
plate off.

Rob

Just replying to my own post to say that I found that the end bearing
is clamped into the end part of the body by inner and outer plates
screwed together through the body end, and is not tight so the end
part of the body came off with no bother after all that. I've now got
access to the coils !!

I know this is not the sort of problem we all tackle but with the
access to affordable 240v inverters, this modification is becoming
more popular, so I'm taking some photos as I go along and will post
the link to them in due course.

Rob