Adcock Shipley Bridgeport motor

[colin hamiltonParticipant @colinhamilton16803]

Mike and Clive thanks. Given the actual use mine will be getting I feel OK about securing with zip ties

[KWILParticipant @kwil]

What is the temperature rating of a zip tie? Methinks theyy will get very soft at normal motor operating temperatures.

[colin hamiltonParticipant @colinhamilton16803]

Check out what I found!!

Edited By colin hamilton on 28/01/2022 19:17:46

[colin hamiltonParticipant @colinhamilton16803]

[Mike PooleParticipant @mikepoole82104]

The shellac we used sounds vey like the stuff you have Clive, we baked all our motors to harden the shellac and after baking it had set quite hard. I am not sure what the bake temperature was. I am not so sure as Clive that the connection of the coils doesn’t matter but if if doesn’t run sweetly then swap each winding in turn until it runs best. Motors can run at quite a high temperature without stress, in fact we have had to strip and bake motors that have been flooded to dry them out. Modern motors can run happily at temperatures that would be very uncomfortable to put your hand on for any time but to reach those temperatures they need to run at full load for extended periods. It looks like the star point extraction has gone well so good luck with the final assembly and testing.

Mike

[AJAXParticipant @ajax]

Standard cable ties (non heat resistant) made from 66 nylon are suitable for use up to 85 degrees C. I would remove those ties and use string sprayed with conformal coating, or use heat resistant ties instead. You won't know what is happening inside the motor until it fails.

[John HaineParticipant @johnhaine32865]

It is important that the sense of each winding is correct, it doesn't just reverse the motor if you reverse one winding, the motor torque will suffer and it won't run so smoothly. This is because there is mutual coupling between the windings of a 3 phase motor and if the couplings are not all in the same sense the phase currents are unbalanced.

But it should be easy, if you connect the inner end of one winding to the outer of the next. Or putting it another way, the end that went to the star point of one goes to the not star point end of the next.

[noel shelleyParticipant @noelshelley55608]

As John has said, Now you have star point it SHOULD be easy ! If you take the 3 original wires as 3 starts, Test continuity, to the 3 tails at star point and take these as 3 finishes, then, start No1 to finish of No3 coil, finish of No 1 to start No2,finish of No2 to start of No3 ! You now have a 240v 3phase delta wired motor. IF it rotates in the wrong direction simply swap any 2 incoming phases. It is very important to re coat the work to prevent windings moving, breaking the insulation and causing shorted windings. Good luck, Noel.

[CirclipParticipant @circlip]

Years ago, rewound the stator coil on a Citroen alternator. This was vacuum impregnated with an epoxy resin after winding. This material was what was used to do transformers at the R&D labs for Decca R&T. not only to waterproof them but also to stop the windings 'Singing' in use.

When the first workshop machinery arrived from Taiwan many years ago, the first job after cleaning the sand from the castings (how times haven't changed since ROC took over) was to change the motors for Brit impregnated varieties. Insulation breakdown due to singing windings was a regular occurance.

Regards Ian.

Edited By Circlip on 29/01/2022 12:18:15

[john fletcher 1Participant @johnfletcher1]

Colin, I've sent you a PM regarding getting the phasing sense correct and how to do it should you need to do. I have more details should you be in need of them. John

[Clive SteerParticipant @clivesteer55943]

I believe that a standard 3 phase motor is a symmetrical machine so winding "polarity" shouldn't be important but I stand to be corrected.

However for a 2 speed 3 phase motor, using a Dahlander winding configuration, winding "polarity" is important as the flux coupling from each winding interact to change the stator pole pattern from 2 pole (Hi Speed) to 4 pole (Lo speed). The special winding arrangement is also the reason why a Hi Volts 2 speed motor cannot be changed to a Lo Volt motor in the same way Star can change to Delta.

I will experiment with a 3 phase motor I have to check if my thinking is wrong.

Clive S

[Clive SteerParticipant @clivesteer55943]

I have just concluded my experiment which proves my thinking was incorrect and winding "polarity" is important. With one phase winding reversed the motor vibrated and had very low torque.

I will give myself a serious talking to.

So Colin, as has already been said by others, the wires joined to form the "star" point can be regarded as starts.

Clive S

[colin hamiltonParticipant @colinhamilton16803]

All done and running smoothly. Once I got the star point it was pretty straight forward to make sense of the polarity. I just labelled everything up (u1, u2 etc) and followed the classic delta diagram from the net.

I've gad a quick look online and the proper lacing is available so I will definately replace all of my cable ties.

The whole mill is a bit tired so I'm going to tear it down for a proper clean and repaint. Stand bye for more questions!!!!

Clive – Next time you are in Wiltshire please let me know so I can buy you a pint!!!

Cheers

Colin

ng up

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