Siemens-Schuckert 3 speed induction motor repair.

Use this forum to discuss any general matters that do not fit into any other forum.

Siemens-Schuckert 3 speed induction motor repair.

Postby glowinganode » Thu Mar 31, 2016 9:13 pm

I'm currently restoring a vertical milling machine fitted with a Siemens-Schuckert 3 speed pole-changing induction motor.
Whilst dismantling the machine I noticed the insulation on the motor wiring was cracked.
The wiring appeared to be cloth covered rubber insulation, which had gone hard and lost its flex.
The motor was dismantled and the stator winding placed on the bench.
The original wiring was cut back leaving tails approx 1" long.
New lengths of 1.5 mm^2 tri-rated equipment wire were soldered to the tails and insulated with a layer of heat-shrink sleeving followed by a layer of heat resistant braid.
Pleased with the end result and glad I took the plunge, see attached photos.
Rob.
Attachments
020(1).jpg
020(1).jpg (78.64 KiB) Viewed 10398 times
019(1).jpg
019(1).jpg (92.75 KiB) Viewed 10398 times
018(1).jpg
018(1).jpg (91.2 KiB) Viewed 10398 times
glowinganode
 
Posts: 45
Joined: Fri Nov 30, 2012 11:02 pm

Re: Siemens-Schuckert 3 speed induction motor repair.

Postby glowinganode » Thu Mar 31, 2016 9:14 pm

More photo's...
Attachments
031(1).jpg
031(1).jpg (101.45 KiB) Viewed 10397 times
032(1).jpg
032(1).jpg (90.77 KiB) Viewed 10397 times
glowinganode
 
Posts: 45
Joined: Fri Nov 30, 2012 11:02 pm

Re: Siemens-Schuckert 3 speed induction motor repair.

Postby Lucien Nunes » Sun Apr 03, 2016 5:35 pm

It's nice to see a pole-changing motor still in service rather than being replaced by a VFD. A rationalisation of our workshop last year unfortunately led to the retirement of the last two machines with this type of drive. One was a Leinen LZ toolroom lathe with a 3-speed of unknown make. IIRC this model had also been available with Ward-Leonard drive. The other was a Newall fifteen-twenty vertical borer with a Newman motor. Rather than a separate control switch as on the Leinen, the spindle-speed selector of the Newall operated both the mechanical gears and the motor speed selection contacts which engaged the appropriate contactor. 3 electrical speeds and four gears gave 12 speeds from 66 to 3000 rpm.

We have a selection of interesting machines at EK but there are certain types of drive that are definitely on the wants list. These include pole-changing motors, Schrage motors, and a good commercially made Ward-Leonard setup rather than a home-brew. The first we might get in a 1970s washing machine, the last in a high-speed lift, but the Schrage motor is now a rare beast and I wonder whether we will ever find one.

Leinen lathe.jpg
Leinen lathe.jpg (314.36 KiB) Viewed 10390 times

Leinen motor.jpg
Leinen motor.jpg (302.47 KiB) Viewed 10390 times

Leinen speed switch.jpg
Leinen speed switch.jpg (260.12 KiB) Viewed 10390 times

Newall 15_20.jpg
Newall 15_20.jpg (141.81 KiB) Viewed 10390 times

Newall motor.jpg
Newall motor.jpg (144.19 KiB) Viewed 10390 times

Newall contactors.jpg
Newall contactors.jpg (205.4 KiB) Viewed 10390 times
Black was always meant to be a phase. The neutral phase.
Lucien Nunes
 
Posts: 320
Joined: Fri Apr 18, 2008 12:26 am

Re: Siemens-Schuckert 3 speed induction motor repair.

Postby glowinganode » Sun Apr 03, 2016 9:43 pm

Unfortunately I have no choice but to use a VFD, as I only have single phase 230 V on the premises.
I have successfully used a Chinese HY inverter on my lathe for over a year now, and would never look back now.
Unlike the lathe motor however, the windings cannot be connected for 230 V so I'm going to have to step up to 400 V first.
I guess it would be best not to operate the pole changing switch on-load when fed from a VFD.


Cheers for now.
Rob.
glowinganode
 
Posts: 45
Joined: Fri Nov 30, 2012 11:02 pm

Re: Siemens-Schuckert 3 speed induction motor repair.

Postby Lucien Nunes » Mon Apr 04, 2016 8:20 am

Hopefully being of good manufacture and living in a cool clean location life atop the mill, the class A insulation will withstand the high dV/dt of the VFD. Opinion seems to vary about the likely lifespan, I do try to avoid inverters and soft-starters where possible with very old motors, by championing the cause of the original control gear. If it were mine I'd hang a sign on the speed switch as a reminder to shut down the inverter before changing, as I'm sure you're right about it being a quick way to zap the output bridge.
Black was always meant to be a phase. The neutral phase.
Lucien Nunes
 
Posts: 320
Joined: Fri Apr 18, 2008 12:26 am

Re: Siemens-Schuckert 3 speed induction motor repair.

Postby glowinganode » Tue Apr 05, 2016 9:46 pm

Lucien Nunes wrote:....and living in a cool clean location life atop the mill....


The motor assembly mounts on the rear of the column and is a heavy chunk.

007(1).jpg
007(1).jpg (100.7 KiB) Viewed 10354 times


It consists of a sandwich of a mounting plate, the motor proper and the rear housing.

005(1).jpg
005(1).jpg (98.12 KiB) Viewed 10354 times


Motor replacement after overhaul.

009(1).jpg
009(1).jpg (116.2 KiB) Viewed 10354 times


Rob.
glowinganode
 
Posts: 45
Joined: Fri Nov 30, 2012 11:02 pm

Re: Siemens-Schuckert 3 speed induction motor repair.

Postby clivep » Wed Jun 01, 2016 5:18 pm

Nice neat job with the motor rewire. However I think that the cable ties are likely to go crispy after a couple of years and may well come adrit

Clive
clivep
 
Posts: 85
Joined: Wed Sep 30, 2009 10:01 am
Location: West London

Re: Siemens-Schuckert 3 speed induction motor repair.

Postby mcmurdo » Mon Dec 04, 2017 8:05 pm

Lots of lovely old motors like this still in action, one of my clients has a plastic moulding machine with a variable brushgear/donkey motor for speed control of the extruder. Another client, who runs a large travelling fair, still uses an open-face resistance starter for the waltzers, complete with open knife switches. (not a preserved fair, just a normal fair).
mcmurdo
 
Posts: 11
Joined: Sat Sep 09, 2017 2:59 pm

Re: Siemens-Schuckert 3 speed induction motor repair.

Postby Lucien Nunes » Fri Dec 08, 2017 5:05 pm

The variable-speed AC motor on the extruder is interesting. These used to be quite plentiful in industry but are now hard to find. We definitely need a couple of examples for the collection. Googling 'Schrage motor' got a number of hits from Indian technical traning materials, which made me think that many old examples have been shipped over there attached to the many old redundant British machines that have been exported due to factory colsures and CNC upgrades.

110V DC rides with resistance speed controllers are also dwindling but still around. It's many years since I had the free time to visit fairs on a regular basis so I'm no longer in touch with the people I knew who kept me abreast (3-abreast?) of trends and news. I used to get World's Fair newspaper too, and often saw ads for DC machines that were being replaced. Must get out more...
Black was always meant to be a phase. The neutral phase.
Lucien Nunes
 
Posts: 320
Joined: Fri Apr 18, 2008 12:26 am


Return to General discussion

Who is online

Users browsing this forum: No registered users and 1 guest

cron