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accordlx (Electrical) (OP)
16 Sep 10 7:41
We recently recieved a 3 speed 2 winding marine winch motor for rewind in our shop. The motor had been recently rewound at a shop in Russia. The rewound motor never worked properly and actually failed shortly after installation according to the ship's engineer. I have tried to get winding data from the factory but they will not give it out citing proprietary policy.
I have included attachments that describe the motor as well as the winding data that we took out of the motor. I'm hoping someone has seen a similar motor or has information as to how they are able to get 17/86 KW & 2 pole/ 4 pole from the same winding. The 8 pole winding is a separate winding that is controlled by a separate contactor in the controll box.
zlatkodo (Electrical)
16 Sep 10 9:18
Hi, accordlx,
Unfortunately, I do not see any winding data in your attachment.
Zlatkodo
accordlx (Electrical) (OP)
16 Sep 10 9:24
Here is the data
accordlx (Electrical) (OP)
16 Sep 10 9:26
zlatkodo (Electrical)
16 Sep 10 10:00
Can you draw, the internal connections for 2 / 4 poles that you have found?
 Do you have any information what are the no-load or full-load currents for this internal connection?
Zlatkodo
accordlx (Electrical) (OP)
16 Sep 10 10:10
accordlx (Electrical) (OP)
16 Sep 10 10:11
The currents that I have from the customer are on the 1st attachment
zlatkodo (Electrical)
17 Sep 10 0:46
Hi, accordlx,
2 / 4 pole diagram for this particular case should look as shown in the attachment.
This diagram you need to compare with this one what you found , and then decide whether it will apply or not.
My calculation shows that the number of turns (3 turns / coil) is OK for this winding.
But for the 8 pole winding I get a bigger difference.
Therefore I need some more explanation.
Whether you're (at the first inspection of the defective motor), found which coil is faulty  (8 pole or 2 / 4 pole)?
You must know that the calculations are made for continuous operation (S1). Here it is not the case, because the motor is designed for S2  and both windings can be more or less overloaded.
Zlatkodo
 
accordlx (Electrical) (OP)
17 Sep 10 7:37
The 8 pole winding worked OK according to the customer. The 2/4 pole winding is what failed and actually never ran properly. He did not elaborate on exactly what was the problem.
koizumi (Electrical)
18 Sep 10 4:04
You have to make clear what is the problem with the motor running with 2/4 pole winding, before consulting others about that matter.
 
accordlx (Electrical) (OP)
18 Sep 10 9:36
The problem is that the motor was wound by another motor shop and the customer says it was wound with incorrect data. We can't get data from the factory. The 2/4 pole winding was completly burnt up when we got it in our shop so we were not able to run it here in order to try to diagnose the problem. What I am looking for help with is if anyone has seen a motor like this before and has winding data or if someone knows of a way you can engineer a single winding to put out 17 KW on the 2 pole winding yet still be able to get 86 KW out of the 4 pole winding. This is what doesn't make sense to me.  
Helpful Member!  waross (Electrical)
18 Sep 10 15:40
I would consider the possibility that it was originally wound for 900/1800 RPM and the 3600 RPM was the separate winding.
 

Bill
--------------------
"Why not the best?"
Jimmy Carter

zlatkodo (Electrical)
19 Sep 10 2:57
1. -  Is there more information on the motor-nameplate?
2. - Do you have the possibility to check what is the switch-combination in place  where the motor is running? At what speed is achieved star-point?
Without new informations, I doubt that you will solve this problem. This winding can be any (maybe 3 separate windings, also).
Zlatkodo
desertfox (Mechanical)
19 Sep 10 7:41
Hi accordlx

I have two questions:-

1/ How does the customer know it was wound with incorrect data?

2/ Why isn't the shop who wound it taking responsibility?

desertfox
edison123 (Electrical)
19 Sep 10 9:16
"a single winding to put out 17 KW on the 2 pole winding yet still be able to get 86 KW out of the 4 pole winding".

That's odd.

Muthu
www.edison.co.in

edison123 (Electrical)
19 Sep 10 9:59
BTW, the 8 pole winding is supposed to be on top of the 2/4 poles winding. i.e 8 pole must be the nearer to the air-gap. Did you check that is the case here ?

Muthu
www.edison.co.in

koizumi (Electrical)
20 Sep 10 5:04
I have the same idea with waross, that the original configuration for this motor is 900/1800rpm one winding, and one separate winding is 3600rpm.
I deduced that according to zlatkodo's 2/4 pole diagram, the 4 pole winding could be overheated. Because this is only a single-star (1 path parallel) to carry the full 155A current. I don't know what size are #15 and #16 wires, but I guess the current density could be too high.
edison123 (Electrical)
20 Sep 10 8:05
Bill. Nailed it. Your argument makes much more sense. A 2 pole winding designed for 17 KW. And a 8/4 pole winding for 43/86 KW with Y/YY connection.

A lps for thinking out of the box.

Muthu
www.edison.co.in

zlatkodo (Electrical)
20 Sep 10 8:59
In my earlier post I gave a scheme for the 1Y / 2Y variable torque, because it is Acordlx suggested in his attachment ( 1Y/2Y variable torque connection - 6 leads ), regardless of the technical data from which you can not see  most important thing (connection).
Given that the manufacturer's information is unknown, now is the question  what type of winding is suitable for such a facility. Maybe it's not 1Y/2Y, maybe is 1D/2Y or three separate windings, or maybe.....? To much "maybe" and "if" !!!
Therefore I repeat my earlier question:
1. -  Is there more information on the motor-nameplate?
2. - Do you have the possibility to check what is the switch-combination in place  where the motor is running? At what speed is achieved star-point?
By the way:

Quote (Edison123):

Your argument makes much more sense. A 2 pole winding designed for 17 KW. And a 8/4 pole winding for 43/86 KW with Y/YY connection.
Note that in 1Y/2Y connection  low-speed HP is only 1/4 high-speed HP, not 1/2.
Zlatkodo
edison123 (Electrical)
20 Sep 10 9:17
Why only 1/4th ?

Muthu
www.edison.co.in

edison123 (Electrical)
20 Sep 10 11:15
My calcs for the 8/4 pole Y/YY winding (top winding)

Coil Pitch - 1 to 9

Turns per coil - 3

Long jumpers (coil group 1 to coil group 7)


***********************************************

2 pole Delta winding (bottom winding)

Coil Pitch - 1 to 17 (2/3rd pitch)

Turns per coil - 4

Winding circuits per phase - 2 in parallel

 

Muthu
www.edison.co.in

accordlx (Electrical) (OP)
21 Sep 10 21:22
To answer some of your questions-
The ship engineer says the controls are set up so that the 8 pole is on one set of contactors and the 2 pole /4 pole on another other set.. I'll try to get a copy of the control schematic and post it.
 
Our initial assumption also- The 4 pole/8 pole must be one winding and the 2 pole the other.

The 8 pole winding is positioned closest to the rotor.

I don't know why the motor shop that did the original rewind is not being held responsible for rectifying the problem.

Zlatkodo is correct when he states that the HP ratio is 4-1 with a 2-1 speed ratio when using the VT connection.
accordlx (Electrical) (OP)
21 Sep 10 21:33
Our strategy at this point is to wind the motor with the turns, wire size, and coil spans ( I can't see how they could have made an error with these) we found in the motor when we got it and bring out 12 leads on each of the windings. We can then play around with different configurations and see which works the best.
edison123 (Electrical)
21 Sep 10 23:41
Looking at that nameplate you posted, it's not a variable torque connection for 8/4 pole. It's a constant torque at those speeds. Variable torque connection is what the previous rewinder mentioned it as, not the OEM.

Whether the connection is Y/YY or D/DD is immaterial.  

P = kNT. I'm sure the previous rewinder goofed it.

Muthu
www.edison.co.in

zlatkodo (Electrical)
22 Sep 10 0:15
Hi, Acordlx,

Quote (Acordlx):

I'll try to get a copy of the control schematic and post it.
It is a good decision.

Quote (Acordlx):

Our strategy at this point is to wind the motor with the turns, wire size, and coil spans ( I can't see how they could have made an error with these) we found in the motor when we got it and bring out 12 leads on each of the windings. We can then play around with different configurations and see which works the best.
Do not forget to record a no-load currents for all connections. I expect a  high values, especially with  8 pole winding. You gotta know that, sometimes in these cases, is a very important one winding relative position compared to other, but this is a specific topic that requires a lot of analysis.
I wish you success.
Zlatkodo

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