Printed from www.nzmeccano.com
My E15R Motor
(Author: Arup Dasgupta (ISM 652))
A repair story
Figure 1: The E15R Motor with box and leaflet
I always wanted a Meccano electric motor. The cricket ball motor was available in the 50’s in India but at a cost which was beyond my modest means. So recently, when I found an E15R available on eBay, and I had just conquered my fear of using my credit card on eBay with PayPal to protect me, I decided to make a bid. In fact I went whole hog and bid for an E15R, a Crane Motor and a six speed Power Drive motor as well. I usually lose most bids on eBay because the ending is when I am fast asleep and I haven’t mastered all those bidding tricks, so I get outbid. But these were different. They were ending at 11 pm so I could take care of any snipers. But I needn’t have worried. The recession is not all that bad. There were no more bids, so I won all three.
The E15R and Crane motor were from the same seller and I got them in a week’s time. The Crane motor worked well but the E15R refused to budge. I could feel the rotor lock so it was electrically live. A few drops of oil on the armature shaft got the motor going for about two seconds before it jerked to a sudden stop with a ‘oh oh’ kind of a clunking noise. Close examination showed that one side of the armature winding had come off the commutator. It was rather poorly soldered to begin with and the long journey plus the spin up caused it to give way.
Figure 2: The motor disassembled. Note the black stuff on the commutator and the disconnected armature winding with a blob of solder at its tip. The motor was otherwise quite clean
Closer examination revealed a brush that bashfully retreated into its holder at the slightest opportunity. The commutator was covered with a black sticky layer of something. The brushes were ‘held’ by the lead of a capacitor pushed through the last turn of the brush holding spring. I couldn’t believe my eyes! Had I picked up a lemon? An appeal to Spanner was informative. Richard Payn was of the opinion that the spring was the culprit and the bad news was that springs were impossible to find. Geoff Brown suggested a way to open up the motor and tips on cleaning the brushes. So armed with this information I decided to try and fix the motor.
Removing the four nuts holding the side plate opposite to the side holding the brushes released the side plate and the armature came out easily. I sprayed the commutator with tape recorder head cleaning fluid and used a cotton bud to remove the sticky black layer. It took several sprays and buds before the copper shone through. Next I heated and removed the solder blob from the armature lead that had worked loose. I applied a thin layer of solder on the commutator edge and then soldered back the armature lead. A light application of a needle file was needed to remove the excess solder to ensure that it didn’t foul with the stator.
Figure 3: Close up of the brushes after being teased out of the holders. Note the sticky stuff.
I turned my attention to the brushes. I teased out each brush using a jeweller’s screwdriver and a pair of tweezers. The reason for the ‘bashfullness’ of the brushes became clear. The brushes were coated with the same sticky stuff I found on the commutator. More application of the cleaning fluid removed the sticky stuff and after a few repetitions of this treatment I could make them slide in and out of the holder freely. I sprayed on a coat of ‘Zorrik 88’ recommended for cleaning and lubricating distributor points and spark plugs.
The rest of the motor was quite clean and did not require any drastic treatment. After the spray dried out, the armature was put back and the brushes teased back using the jeweller’s screw driver to seat them on the commutator. The side plate was replaced and the test run was a success. The commutator still kept getting coated but application of the cleaning fluid on the tip of a cotton bud two three times cleared up the residual contamination.
Figure 4: Reassembly after the repairs. The new solder joint can be seen as well as the brushes, now properly seated
I measured the current drawn from the DC source. No load drain was about 0.6A. Stalling the rotor pushed the drain to 0.8A. I think this is quite normal. So, I now have a motor which I had long desired to own. As I was testing the motor my daughter walked in and asked “what is this smell?” It’s my motor; it’s working and what she was smelling was the ozone!
I have added a few pictures of the steps in the hope that it may help another Meccano-person who may face the same problems. This is a small pay-back for the invaluable help I got from Spanner.
Figure 5: The spinning motor! Can you see the spark between the brush and commutator?
Figure 6: My tools for the job. I use a head mounted magnifier for convenience
Total number of messages on this page: 9. This is page 2 of 2.
jose hernandez (at 4:48pm, Sat 7th Jan, 12)
i`m looking for the E15R motor
can you tell me how can I get it?
SAMUEL SAMARAGO (at 6:59am, Sat 10th Jul, 10)
Ron Corry/Ireland (at 10:32am, Sun 24th May, 09)
Thanks for posting this. It has given me some good ideas with regards to my own E15R.
On a different note, I'm sorry that you have such bad memories of your C.B. Teacher. It seems that you were not alone in receiving rough treatment; have you seen comments on the Ryan report published in Ireland last week which details the extremely bad treatment accorded to pupils here in State Institutional care over very many years? It makes very sad reading.
Anyway, back to Meccano. The Corlust M.C. attended another model railway exhibition in Bangor N.I. yesterday. It was a great success; Ian even had his Mamod/Meccano live-steam "engine" running around an O gauge track all day!
All the best, and thanks again.
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