Thread: Removing Mill Motor

As I do not have 415 Vac 3-phase power in my workshop, my recently acquired Kondia Powermill FV1 needs a VSD and the motor matched to the 240 Vac output of the VSD.

I must remove the motor to reconnect it internally to 240Vac 3-phase or, if the reconnection fails, replace it with a new 240Vac 3-phase motor.

But, the pulley on the motor shaft is bigger than the hole in the casing.
The handbook cross-section drawing shows the pulley bigger than the hole.

My plan is to chock the motor as high as possible above the hole (pulley in contact with the casing) and reach into the space made below the pulley with a socket to remove the pulley retainer bolt.

Then lever the pulley off inside the casing as the motor lifts up.
I think the pulley could then come out sideways.

Am I missing something ?

I have ordered a Bridgeport Maintenance Manual CD to improve my knowledge of how to attack this job.

Happy machining,
John.

Well, the obvious thing I missed was that the hole in the casing is oblong with the extensions directly below the bolt attachment points.

This, I discovered, only after removing the timber chocks in the area and replacing with pipe spacers and studs to clamp the motor while I attacked the pulley screw.

All I had to do was grip the motor and tilt it about 45 degrees towards the ram and wiggle the pulley through the hole.

Now, the interesting aspect of attempting to re-connect internally to 240 Vac 3-phase.

Happy machining,
John.

Is there 12 terminals under a cover on the side of the motor like this?:

Graziano,
Thanks for taking the interest.
No, unfortunately, the motor has only 6 terminals.

Motor rating is 2.5/1.5 kW 3000/1500 rpm 415 Vac 50 Hz.

The connection is star for one speed and delta for the other,
The nameplate does not indicate which connection goes with which speed, but my investigations lead me to believe the winding is arranged per the attached diagram.

Coils in parallel for each leg of the star to give a 2-pole flux and 3000 rpm.
Coils in series for each leg of the delta to give a 4-pole flux and 1500 rpm.

My hope (hardly a plan at this stage) is that I can get internally to both ends of all 6 coils and to bring out all the ends (12 terminals) to the connection box.
In the connection box the coils would be arranged as two separate deltas connected in parallel as a 2-pole motor.
Probably the same as the delta-delta 220 V connection shown in the image that you referenced.

Right now, I cannot get the NDE endplate off the motor.
Tomorrow I will make a puller to suit.

If I can get at the coils, I would like to check polarity of each coil and its physical location in the total winding.
I think a low voltage supply (battery ?) to power each coil in turn and a compass to check polarity and location should give sufficient information to get the coil connections correct.
Do you have a better suggestion ?

Happy machining,
John

Ok, if it's a real 2 pole/4 pole, two speed, three phase motor then all bets are off. My brain is beginning to melt trying to think of the various combinations . Do you have a Kondia manual showing configurations?. This page show the voltage configurations as 208/230/460V three phase but say nothing about two speed motors though : http://www.sudetco.com/Clausing/ClausKonidaFV1.htm

If it's exactly as per your diagram then joining 1,2&3 should do what you want by paralleling each of the two windings that each phase has which would halve the voltage requirement as per the diagram with no extra wires neccessary.

Edit: Here's the Kondia tech support enquiry form which does cover the FV-1, if they are anything like Jafo who made my mill then they'll email you the relevant page from their manual.
http://www.kondia.com/support.php?idioma=3

Graziano,
Connecting 1, 2 & 3 together is the 415 Vac 3000 rpm star connection.
Each coil gets only 240 Vac, but the vector addition at 120 degrees results in line voltage of 415 Vac.

To get 3000 rpm 240 Vac, the line voltages have to be connected directly to each coil.

I hope to make one delta with coil 43 on one leg of the delta, then coils 52 and 61 for the other legs.

The second delta would be coil 41 on one leg, then coils 62 and 53.

The two deltas are then wired in parallel.

Good in theory !!!

Happy machining,
John.

Ahh yes you're right, you would have to access each phase winding separately and then stick the lot in delta. Ideally the manufacturer has some easy method if they specify a 230V mode of operation.

Graziano,
I got the motor apart and investigated the windings.

Unfortunately, the wiring to the terminals is single core tinned copper with the coil connections buried deep within the windings.

When manufactured, the coils would have been loaded, the coil connections made, then the coil ends pressed/hammered over and finally lacquer applied.

Too deep and difficult for me to do anything with the coil connections in a home workshop.

I will take the motor to a friends workshop fitted out with 415 Vac 3-phase and test it, then put it on ebay.

Now searching for a 240 Vac 3-phase motor/inverter package for a Bridgeport style turret mill, any suggestions ?

Happy machining,
John.