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Discussion Starter · #1 ·
I am looking for information for the connection of a four speed motor. If someone can point me in the right direction that will be great. The motor is a Crompton Parkinson 3 phase 415 volts and 25 bhp. The motor is on a lathe to give different speeds thats the eazy part. The motor has two nameplates so it is actually two motors in one. Each with two speeds.
the rpm - one is 720/480 and other 1460/970 (australia has 50 hz)..still eazy. This is where i come unstuck. Each 2 speeds has 7 wires terminating That makes 14 terminals on the motor. Six wires i can handle but 7 :huh:
 

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I am looking for information for the connection of a four speed motor. If someone can point me in the right direction that will be great. The motor is a Crompton Parkinson 3 phase 415 volts and 25 bhp. The motor is on a lathe to give different speeds thats the eazy part. The motor has two nameplates so it is actually two motors in one. Each with two speeds.
the rpm - one is 720/480 and other 1460/970 (australia has 50 hz)..still eazy. This is where i come unstuck. Each 2 speeds has 7 wires terminating That makes 14 terminals on the motor. Six wires i can handle but 7 :huh:

There are several Aussie Electricians here that will know the answer to your question..


Good luck and Welcome to the forum..:thumbup:
 

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Discussion Starter · #5 ·
the motor does not have a wound rotor. And and it looks to have only one set of windings in use at any time. the motor is stopped to do a speed change there is no need for a drum controller on a lathe. but it does reverse. the thing did work but when they upgraded the starter they were only able to set up the slow speed and put the rest in the too hard basket.
 

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Is this thing a wound rotor running in a cascade with a squierrl cage in order to share the load?

Or is one motor on a totally open circuit while the other is running?
It sounds like a two winding, four speed motor. We built a lot of them, at the firm I worked at for thirty-three years. Ours were numbered T-1 thru T-7 for the 1st winding. T11 thru T17 for the 2nd winding. One winding for first and third speed. The other for second and fourth speed.
The Louis Allis Co. Milwaukee, Wisconsin.
 

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It sounds like a two winding, four speed motor. We built a lot of them, at the firm I worked at for thirty-three years. Ours were numbered T-1 thru T-7 for the 1st winding. T11 thru T17 for the 2nd winding. One winding for first and third speed. The other for second and fourth speed.
The Louis Allis Co. Milwaukee, Wisconsin.
Is this now obsolete, because of VFD's ?
 

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Is this now obsolete, because of VFD's ?
No. They still build them. There will always be applications where they can be used and there will always be customers that are afraid of change. I had a customer down all weekend because he was afraid to replace an AB timer, with another brand. Same exact timer. Same wiring scheme too.

OP. Two speed motors can come two winding or one winding. You have two options. Contact your local motor shop and let them show you how to connect it. Or, contact the lathe manufacturer for a wiring diagram. This is for sure a proprietary motor. It is not standard. You need the phone number for the OEM. Its them or the motor shop.
You might be able to figure this out. But testing it could cause damage. So, be careful.
 

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Is this now obsolete, because of VFD's ?
The last twenty years of employment at LACO I was in electrical maintenance, so I lost track of buying trends. Some of their customers would order the same items, they were buying for years. This firm was a custom builder of motors to suit each customers requirments. VFD's really changed the whole picture of speed control.
 

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If you only have one HP rating, the connection would be:
Low speed:
L1 - lead 1 Tie together 4-5-6-7
L2 - lead 2
L3 - lead 3

2nd speed:
L1 - lead 11 Tie together 14-15-16-17
L2 - lead 12
L3 - lead 13

3rd speed: Leave open 1-2-3
L1 - lead 6
L2 - lead 4
L3 - lead 5-7

4th (high)speed: Leave open 11-12-13
L1 - lead 16
L2 - lead 14
L3 - lead 15-17

If you have different hp ratings for the different speeds, then you hook 7-3 instead of 7-5. 17-13 instead of 17-15.
 

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I original poster has two choices. A drum switch to select the speeds or a 25HP VFD. The VFD would be the least expensive and most practical option. A speed pot could be installed on the operator's control station. Some form of speed indicator would have to be included to determine spindle speed.
 

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Discussion Starter · #13 ·
Some background. this lathe was used making artillery guns in the forties and it is currently used to grove 18 tonne rollers for a sugar mill. Yes we will most likely put a vvvf drive with a modern motor. From the nameplate.
rpm 1460/970
BHP 25/25
star 34/36 amps

rpm 720/480
bhp 25/2.5
mesh 40/38
Thanks to all for the enlightenment. I can crack this one now
 

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View attachment 9701

That's the puppy on top
And do not use a VFD on that motor unless you are prepared to rewind it. It could last with a VFD, but I would not count on it. If this motor frame is special you can rewind it to single speed and then go VFD. But installing a VFD and connecting it to this motor may not be a good idea.

It's great we have a motor guy here. "Motorwinder". Thanks!
 

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Some background. this lathe was used making artillery guns in the forties and it is currently used to grove 18 tonne rollers for a sugar mill. Yes we will most likely put a vvvf drive with a modern motor. From the nameplate.
rpm 1460/970
BHP 25/25
star 34/36 amps

rpm 720/480
bhp 25/2.5
mesh 40/38
Thanks to all for the enlightenment. I can crack this one now
The company I worked for had a lathe simular to that one. It was a 40 year old LeBlond with a 25FT bed. Was bought from a used machinery firm. The re-conditioning consisted of a steam cleaning and a paint job. It came through with a DC spindle motor and a 3 phase rapid traverse motor. We removed the DC motor and installed an AC motor, plus VFD. Great combination.
 

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And do not use a VFD on that motor unless you are prepared to rewind it. It could last with a VFD, but I would not count on it. If this motor frame is special you can rewind it to single speed and then go VFD. But installing a VFD and connecting it to this motor may not be a good idea.

It's great we have a motor guy here. "Motorwinder". Thanks!
Till I screw up, and you guys tar and feather me. But thanks.
 

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Some background. this lathe was used making artillery guns in the forties and it is currently used to grove 18 tonne rollers for a sugar mill. Yes we will most likely put a vvvf drive with a modern motor. From the nameplate.
rpm 1460/970
BHP 25/25
star 34/36 amps

rpm 720/480
bhp 25/2.5
mesh 40/38
Thanks to all for the enlightenment. I can crack this one now

I have to dig up my European motor listing and Motorwinder ., You are just about right on the spot with the NEMA connections and our IEC is almost simauir beside we use U V W { the old one were R S T }

Iamthor.,

I have notice you mention star and mesh so therefore I know we are allready aware with star { WYE } but mesh can be Delta so watch out on that part.

The amparage on 720 / 480 T/Min is for consanst HP rating but variable toqure { IIRC the low speed toqure is half what is on high speed }

Merci.
Marc
 
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