This is totally confusing.
{note tht now White is green}

Since I disconnected the whole thing, I got 3 separate windings.

One is the inner winding (0.8mm dia), color coding is Green & Black, which has a R of 2.5 Ω.

Second is the outer winding ( 1.0 mm Dia), color coding Red & Black, which has a R of 1.269Ω.

Third is also outer winding (1.0mm Dia), color coding Blue & Yellow, which has a R of 1.269Ω.
************************************
Now the coding is per the original connection.

So two blacks are joined to give one black. One problem ...

Two blacks are of two windings .

One 0.8mm and 1.0mm . This is the main reason the connections are getting confused. The black is not the center of the two Run windings as we all thought was.


So now what do I do.

Officially I am at a dead end.

Which is the Run windings from these friggin windings and which is the start and how should they be connected.

Connection confusion is tht start of winding to the end of winding, the aiding and opposing field is not a problem or is it ?
(Polarity....confusion....Big headache)

Hold on : BRB

 

Busy here so haven't had time to study the full message. The lower resistance will be the run windings. The higher is the start. To test polarity of the run windings connect them in series. Connect to 120 VOLT supply. The motor will hum but won't hurt the windings at this voltage. Wrap a string around the shaft and give it a spin. If it runs then the windings are series correctly. If it won't run then reverse the leads of ONE of the two and test again. Now you can translate the color of the leads to T1-T2 and T3-T4.

 

The green-black is the start winding and one of these can be labeled as T5. The capacitors and switch will have to be added to the other lead of the start winding the lead exiting from them will become T8.

 

Just what I needed to know.

Thanks a million tinkerman.

One question...Why is the Gilbarco caps rated at 125VAC and yet they work on 220VAC..I ask this cause they were using them until the bearings gave up which was like since they were installed.

And why the run and start are of equal capacitance ? Shouldn't the running capacitance be much lower than the starting one.?

 

If the start winding is connected in parallel with one of the run windings when the motor is operated at 230 volts the start winding is exposed to 120 volts and those caps will work just fine. At 120 volt operation same thing. Yes usually run caps are lower than start. Not common to see the same size for both. Obviously the starting load in this application can't be too high. Heavy starting loads will use a much larger start cap.

 

Thought you said in OP that the caps were replaced by previous "tech"? How do you know they where correct value? Both Debe and I told you the correct cap voltages for the voltages that the motor runs at. But you don't believe me or him now.

This may help to chose a cap value - http://www.lifasa.com/descargas/in/tech_note_motor_i.pdf Page 3.

If you want to kick out the start winding without fixing the centrifugal switch, use a "potential relay" most sealed refrigeration compressors use them. So you might get one from a 'dead' refrigerator.
http://hvacreducationtechtips.blogspot.com/2009/06/potential-starting-relay.html

http://www.grainger.com/Grainger/STEVECO-Potential-Relay-4E654

 

If the start winding is connected in parallel with one of the run windings when the motor is operated at 230 volts the start winding is exposed to 120 volts and those caps will work just fine. At 120 volt operation same thing. Yes usually run caps are lower than start. Not common to see the same size for both. Obviously the starting load in this application can't be too high. Heavy starting loads will use a much larger start cap.

tinkerman, how do you get 120V from a 230V line with no neutral? A 230V motor doesn't use the neutral in its connection, only the two "hots".

 

I think he showed that in post # 16 with his diagram. Center tap concept of two windings in series.

 

You don't need a neutral. The 230 volt windings connected in series act like an auto transformer. Each run coil is 120 volts.

 

Thanks guys.

I am attempting to try as in post #16. Which by the way I cam up before but was a bit confused so I did not try it.

A potential relay is new to me but I will see if I can get my hands on one so I can use it in the wooyun.

 

Caution: didn't you say these motors are explosion proof and were used in a petrol environment? A relay would be fine in some applicaitons but not if it will be returned to it's former service.

 

Ok..So here is me attempting to fix the Gilbarco and test the winding polarity.

I installed the running cap ( the one they say is in the Gilbarco rated at 125VAC, 189 to 227μf) in the back cap.

Extended the wires through stator holes.

And the SC at the front end with the centrifugal switch.

And here is the 110V transformer I am using.
It's a PV2000 Amp Tx rated at 2KVA Secondary has two separate 126VAC center tapped windings

The winding connections are coming out from the front wire inlet.

All are separate, the caps, three windings and the switch. All color coded and labelled to avoid annoying big confusion.

Note

The caps are both 125VAC.

Result and testing.

I connected the Run winding as I thought was the correct way. Gave 63VAC to both ends and it hummed. Rotated the shaft by hand and it picked up speed quite easily....What joy and the same at 126VAC....I cud almost cry.

Measured the Run I = 6A. Quite high I thought.

Disconnected reversed the lower one side and the gave 126VAC and it started to rattle. Current shot to 20 Amps. Hee hee hee.. So This tells me I got it correct at first. {Thanks tinkerman for this valuable info,I couldn't have done it without u.}

I gave 220VAC and the Running current is @ 4 amps.

I checked the center sw and it cut's out perfectly.

So I wired the thing as per tinkernan's diagram which now I knew would work and it started quietly. A success. And it ran for like 10 min. I measured the running cap voltage and was 172VAC. Quite high.

This made me worry. Still the running current is at 4 amps.

So I thought I will run it. Ran it for a few min. The motor was warming quite fast.
I called the Fuel supply guy, he came, still the motor ran and I showed him the RC voltage. And to show him I switched off the motor, let it stop and switch on and the figgin thing started to run across the bench rattling. The current shot to 20 amps.

And end cap was rather hot. Hee hee hee !

So I took it aprt while the guy was here. A liquid started to pour out and the Running cap was like.

It went kaput. I knew it would happen and this time I proved him wrong.

And after the motor cool down I washed and assembled it using RC of 20μf 250VAC and SC of 330VAC 88uf.
Running current drop to 3.54 amps. and I checked by increasing the RC, the current decreases.

Like to know what would be the best value. And from the plate what is the original running current.

Motor is now send to be installed.

Let see what happens.

 

The voltage across the run cap is a vector quanity. It's fine. The switch and end bell is very common manufacture. I can't remember which manufacturer. It's been several years since I did much of this work. At one time I had pails of parts. If I remember my theory correctly you want to reduce the XL to achieve unity power factor. To complicate that it will change with loading so it's a bit of a crap shoot to pick a value of capacitor. One thing you could do is examine other motors in this size range to see what they use. Just a guess but you're probably in the ball park with your 20 mf.

 

The motor works so far. Me got another pay check.

Do you it was my mistake the first one ashed. .

Thanks a lot guys.

 

<quote>
I believe the start winding is ashed as u can see from the picture. The 300μ blew and yet they never checked the motor but put another cap and ran it to it's grave.

See the lamination. Part of the core has been forced to a side but I cannot see any damage on the rotor. What could have caused it. <quote>

This is bad bearing in my experinece. Startor is toast. I have repaired this type of damage but it's a lot of work. Full rewind and before you start all the slots have to be straightened and new papers etc. Not worth the trouble unless very special motor.


<Quote>
I like to know from the more experienced ones. Will the core work in the long run. What would be the effect on the motor rpm and current. ? <quote>

It MIGHT run. A little longer. lol

I did a test on the resistance with a mili ohm meter and there is no short for sure. And I did another test using the Megger to check if any leakage is there from coil to the core. HV check passed. No leaks what so ever in the above field.[/QUOTE]

Maybe not when it warms up.

 

The motor works so far. Me got another pay check.

Do you it was my mistake the first one ashed. .

Thanks a lot guys.

ur welcome. No if I follow the story correctly, the bearings were shot and stator ruined long before it came your way. I'm not so sure about the caps they were fooling with either.

 

I should have added: Check the end bell. If it has a ridge or if the bearing is sloppy in the race it's the cause of all the damage. You may not notice it with the motor assembled as it still could spin freely. However when power is applied the strong magnetic field will pull the rotor to one side and cause hard starting. Place the rotor in a vise and slide on the end bell. You'll know right away how bad things are.

 

R!f@@ had said earlier that the rotor did not show any signs of dragging, hence my suggestion that someone before him had done a mix/match to attempt making one good out of two or more bad motors.